Issued 18 November, 1930
A Lingulid from the Tertiary Rocks of the Waikato District.
[Read before the Wellington Philosophical Society, 11th June, 1930; received by the Editor, 13th June, 1930; issued separately, 18th November, 1930.]
The fossils described in this paper were obtained from two of the coal mines in the Lower Waikato Basin where, owing to the occurrence of faults, it was found necessary to construct inclined drives through rock from one portion of the coal seam to the displaced portion. Fossils were found in part of the strata passed through, and it is unfortunate that at the time no collection was made apart from one or two specimens kept as “curios.” The rock removed in mining was either thrown on the waste dump and subsequently covered over or used in filling old workings, and so is now inaccessible. The rock forming the sides and roof in these drives is badly weathered by the mine air, and for this reason and owing to the timbering required, the number of specimens that can be obtained from their place of origin is small. Outcrops, on account of weathering, afford no opportunity for the collection of fossils.
The collection described and now lodged with the palaeontological collections of the N.Z. Geological Survey, Wellington, consists of a few specimens obtained from the sides and roof of the inclined drives together with a small number which had been kept as “interesting curious.” Although the total number is small, and the specimens imperfect, it is felt that they should be described and their occurrence recorded because brachiopods of this family have not up till now been recorded in New Zealand.
The writer's best thanks are due to Messrs. A. Burt, P. Hunter and C. Hunter, managers of Pukemiro, Glen Afton and Renown Collieries respectively, for their kindness in placing much information at his disposal and in affording him all facilities for making investigations.
The rock containing the fossils to be described is a light grey claystone forming a bed about 40 feet thick resting conformably on the claystones of the Coal Measure Series of the Lower Waikato Basin. In appearance, these two claystones are similar but may be distinguished, e.g., in borehole records, by the fact that the coal measure claystones (locally known as “fireclays”) are usually of a brownish colour and contain frequent dark coloured bands, carbonaceous layers, and nodules of spathic iron ore, whereas the over-lying
claystone with the fossil fauna is practically uniform. In the process of mining, as in stone drives or cross-measure drifts, the claystones of the coal measures are seen to contain bedded leaf remains and irregularly distributed coalified vegetal matter (see Penseler, 1930) which are absent (except in rare instances and in small amount) from the overlying claystone. The difference is therefore that the one rock contains a fossil flora and the other a fossil fauna, the former being a fresh water deposit and the latter a brackish water to marine deposit. The name “Lingula Claystone” is proposed for the latter bed.
Overlying the Lingula Claystone is a bed, about 25 to 30 ft. thick, of bluish green glauconitic sandstone, more or less argillaceous and calcareous in places, which is followed by a thick bed of dark grey claystone. These three beds together are classed as equivalent to the Whaingaroa Series of Henderson and Grange (1926), and with the underlying Coal Measure Series and the overlying Te Kuiti limestones have been placed by Henderson (1929) in the Ototaran Stage of Oligocene Age. The Te Kuiti beds may possibly be of lower Miocene Age, but the Lingula Claystone may definitely be regarded as of Oligocene age.
The Whaingaroa Series represents the first deposits of a marine facies which were laid down on the fresh water (estuarine) coal measure muds as the land was submerged, and the first stage of this submergence, necessarily a shallow water stage, resulted in the deposition of fine grained muds which show no evidence of bedding. Fossils occur scattered irregularly in these clays and may sometimes be missing. The position of this bed with respect to the enclosing rocks is shown in Figs. 1 and 2.
In Fig. 1, a stone drive in the Glen Afton Colliery, the claystones appear uniform to the eye from the base of the drive to the top and no break is noticeable between the coal measure claystone and the Lingula Claystone. Fossils were collected from near the top of the drive, about 50 feet above the top of the coal seam.
In driving the dip shown in Fig. 2 at the Renown Colliery, Waikokowai, lingulids were obtained in the upper part of the drive but were absent in the lower part which passed into the coal measure fireclays where leaf remains were common. Here again no break between the two claystones was seen.
In the Pukemiro Colliery a similar stone drive connects one portion of the seam with the faulted portion about 90 feet higher, and here the stone drive must have passed through the Lingula Claystone. This drive was constructed about 12 years or more ago and there is no record of any fossil having been found, nor can any be seen now in the sides of the drive. Possibly the fossils are missing from this locality or may occur higher in the bed because the drive passed through the lower part only. Again no break can be seen in the succession.
It is evident therefore that the two series are conformable and that a transgression of the sea occurred over the slowly subsiding land surface. There is a gradual transition from fresh-water to marine conditions. There was apparently no difference in the kind of sediment brought down by the river, but, whereas previous deposition had been under fresh-water conditions in a large estuary with accompanying characteristic irregularity, the muds were now laid down under brackish to marine conditions. With increase of salinity of the water it was possible for a shallow water marine fauna to exist.
Description of Fossils.
Genus: Lingula Bruguière.
Dimensions: Approximate length 26 mm.; breadth 14 mm.; ratio 1.85.
Locality: Stone drive, Main Rope Road, Renown Colliery, Waikokowai.
Shell oblong oval, the length not quite twice the breadth. From the point of maximum breadth the shell tapers slightly to the anterior margin which is formed on a slight curve of large radius, and has rounded corners. No median projection, such as often occurs in
Lingula, is present. Posteriorly the shell narrows more rapidly and is produced into an umbo which is probably blunt though no shell was found with the beak intact.
The exterior of the shell has usually a rounded median ridge or carination, high and narrow near the beak but diverging and flattening towards the anterior margin. According to Morse (1902, p. 321), from a study of living forms, this marked ridge especially in the small lingulids and Glottidia is due to warping and shrinkage of the soft tests on drying and “has no existence in nature.” He stated that even in the larger and heavier shells, e.g., L. anatina, where a heavy deposit of lime renders the shell more rigid, “a region of the shell extending in a median line from the peduncular end is generally represented a little more arched than in nature.” Johnston and Hirschfeld (1920, p. 56) state in regard to L. hians, a recent species, that “dried specimens became more or less distorted especially towards the umbonal end, where the valves contracted laterally in such a way that this portion of each became higher, narrower and more pointed than under natural conditions.” Their proper shape was restored on immersion in warm water. It appears therefore that this ridge is a secondary feature and is more marked with the smaller and softer forms of lingulids.
The colour in the specimens collected varies from light brownish yellow or buff through dark amber to dark brown or nearly black. In the darker shells a distinct greenish tinge may be seen towards the centre of the valve. The largest shells are the thickest and the darkest; the young and small forms shown in Figs. 9 and 10, being a light buff to cream colour. Often two shades are present on the one shell marking lines of growth (see Fig. 13).
The shells are brittle, thin, smooth, glistening, and occasionally perforate. They appear to be composed mainly of chitinous material, but the number of specimens is insufficient to warrant the work of sectioning to determine the amount of calcium phosphate present.
Ridges due to increments of growth are well marked and were of assistance in reconstructing the original shape of each shell. As mentioned before, increase of the shell is sometimes accompanied by a change of colour. Radial striations are present near the anterior border.
Muscle impressions are not observable, but on one internal cast (Figs. 11 and 13) there is a well marked median depression which may represent the median septum in the dorsal valve of Glottidia (see Thomson 1927, Fig. 36b, p. 128).
Only single valves were found, with the exception of the specimen constituting the holotype. The shells are incomplete and more or less fragmental, and owing to shrinkage and movement of the enclosing muds they are often to some extent flattened and crushed. The shells of young lingulids are found with those of the mature forms, and are in general more complete. Examples of young shells are given in Figs. 4, 9 and 10. Small fragments of shells also occur scattered throughout the rock.
Comparison of this lingulid with other fossil lingulids has been difficult because no material and scanty literature are available here for such purposes.
Reference has been made to descriptions of fossil lingulids by Davidson (1874), Zittel (1900), Grabau and Shimer (1909), Hall (1847), Reeve (1841), Bittner (1890), and to descriptions of recent species by Blochmann (1892), Morse (1902), and Johnston and Hirschfeld (1920).
No specific affinities were found with any of the fossil lingulids described. With respect to the recent species Johnston and Hirschfeld (1920, p. 79) regard the ratio of length to breadth as constant for each species, and give the following ratios:—
L. hians Swains., 2.3 to 2.47.
L. murphiana King, 2.2 to 2.3.
L. anatina Lam., 2.2.
L. bancrofti Johns. and Hirsch., 2.0 to 2.1.
L. exusta Reeve, 2.2 to 2.5.
L. tumidula Reeve, 1.5 to 1.6.
From illustrations given by Morse (1902, Plate 40), the ratio for Glottidia pyramidata Dall is 2.7 to 3.
As far as it has been possible to determine from the fragmentary shells described in this paper their ratio varies from 1.85 to 1.87, which does not resemble that of any of the recent species quoted above. Schuchert (1911, p. 262) stated that “a survey of the geographic distribution of the inarticulate brachiopoda also shows that all the litoral and shallow water species are bound to warm waters, and that hardly any are common to two zoological provinces.” During middle Tertiary times New Zealand must have been a separate zoological province, as it is at present, and therefore there were probably specific differences between the lingulids here and elsewhere. No recent lingulid is known in New Zealand waters and no other fossil lingulid is known either from New Zealand or from Australia. Comparison of types in this and neighbouring zoological provinces is thus impossible. The description of this newly discovered fossil form given above is sufficient to enable recognition of the species if found elsewhere. For the above reasons the creation of a new species is justified.
Occurring with the lingulid were found Cardium (small), Tellina, Dosinia, and a small gastropod resembling Cylichna or Bullinella. In addition, one large fish scale was obtained from the Renown Colliery locality together with what appears to be portion of a fish bone.
The occurrence of Cardium is in keeping with the brackish and shallow water nature of the deposit, for according to Fischer (1887, p. 1035) it is an “animal marin, saumatre ou lacustre.”
Some recent species of Tellina in New Zealand are found in mud flats at the mouths of rivers.
Tokunaga (1906, p. 69) recorded the occurrence of Lingula hians Swains., in a fossiliferous bed at Oji north of Tokyo, Japan. Associated with this Linguba, which was very scarce, were inter alia two species of Cylichna, six of Tellina, three of Cardium and a Dosinia. Indeterminable fragments of fish bones also occurred; a large number
of fossils was listed from Oji, deep water and shallow water types, and apparently further separation is needed. The age of the beds is probably Pleistocene. This occurrence, though not a parallel to the Lingula Claystone of the Waikato, is interesting as showing a similar association of genera.
The environmental conditions of this fauna may be deduced from their known habits.
Morse (1902) stated that lingulids in general live in very shallow waters on a muddy or sandy bottom, and owing to their remarkable vitality, gradual elevation or subsidence of the coast line would in no way affect their condition. Glottidia pyramidata Dall was found living in great numbers at Beaufort Harbour, North Carolina, on shoals which are exposed at low tides (Morse 1902). Lingula lepidula lives in a few fathoms of water on a sandy bottom at Yenoshima, Japan (Morse, 1902). L. anatina is found at the mouth of the Takahashi River, which empties into the Shimabara Gulf, Japan, in a gravelly and muddy deposit just beyond low tide (Morse, 1902). L. murphiana is not uncommon in the sandy muds between tide marks in certain localities in Moreton Bay, South Queensland, and at the Philippines (Johnston and Hirschfeld, 1920, p. 59). L. tumidula is found in sandy mud at low water (Johnston and Hirschfeld, 1920, p. 51); L. smaragdina Adams from mud at 10 fathoms from Japan and the China Seas (op. cit., p. 53); L. hians is common in mud flats at Noumea, and in the China Sea lives in mud or sandy clay at low water mark, its presence being indicated by the occurrence of oval orifices in the mud (op. cit., p. 59). “The wide distribution of the species suggests that the larva has a fairly extended life and is able to adapt itself to rather wide limits of temperature, since the adult occurs in tropical, sub-tropical and warm temperate waters in the Eastern Pacific.” A species, probably L. hians, was found “buried in a close unctuous mud two or three inches deep” from a muddy bay to the east of Evans Bay, near Cape York, North Queensland. “The fleshy or gelatinous pedicle which passed from between the beaks was five or six times as long as the shell and passed down into the mud, ending in a thickened knob. These pedicles did not appear to be attached to anything. On pulling at the shell a slight resistance was felt but not more than would be caused by the knob being drawn through the narrower hole in which the pedicle lies.” (Jukes, fide Johnston and Hirschfeld 1920, p. 58).
L. exusta occurs in mud close to the edge of the beach sand at Dunk Island north of Rockingham Bay, North Queensland (Johnston and Hirschfeld, 1920, p. 65).
L. bancrofti (op. cit., p. 67) is found in sheltered mud flats on the shores of Hervey Bay, Burnett Head, which are exposed at low tides.
Hayasaka (1922, p. 1) gives the depths of water in which recent species of Lingula occur as follows:—
L. adamsi Dall, 7 fathoms.
L. affinis Hancock, 0-1 fathoms.
L. anatina Brug., 0-1 fathoms widely distributed.
L. jaspida Adams, 7 fathoms.
L. lepidula Adams, 10 fathoms.
L. smaragdina, Adams 10 fathoms.
Schuchert (1911) noted the great vitality of lingulids which he found growing on the tidal flats of Japan, where they are exposed for hours without injury. At high tide they are covered with three or four feet of water. He found further that lingulids lived in brackish water or water so foul with decomposing organic matter that all other shell fish were killed. He quoted Yatsu (1902) stating that the lingulids on little estuaries in certain bays in South Japan may be covered by sand and mud brought down by stream freshets, in which event the lingulids would continue to live by burrowing to the surface by means of their contractile and regenerative peduncle.
Schuchert observed that many species of Lingula occur in bays and estuaries indicating thereby that they prefer a habitat more or less freshened by fresh water.
“The immediate shore line, and often the estuarine bays and deltas, will be indicated especially by the large lingulids embedded in muds and sands with an otherwise sparse fauna.” (Schuchert, 1911, p. 264).
Among recent species of inarticulate brachiopods he found that 24 live between high tide and a depth of 90 feet, and concluded that from the strand line to about 60 feet depth was characteristic of the litoral habits of Lingula.
During life the lingulids were able to crawl about slowly on the surface of the sediments or lie half buried in them (Morse, 1902). By means of their long peduncle, which with the Atremata is a burrowing and prehensile organ and not for permanent attachment to a given place as with all other brachiopods, they were able to draw themselves into the muds or force their way out when necessary. A secretion of mucous by the peduncle agglutinated particles of sand about the posterior end and by this means they are able temporaily to anchor themselves.
“On dying, the body (of Glottidia) protrudes from its burrow and rests at full length on the sand; it gradually turns black as a result of decomposition and the slightest jar causes the body to separate from the buried peduncle and float away.” Morse (1902, p. 318). After death, therefore, the delicate and light shells are liable to be carried away by even the slightest current if sediment is being deposited too slowly to bury them in place.
As regards the fossil lingulids, Thomson (1927, p. 128) stated, “As the animal lives by preference on quite shallow sandy or muddy bottoms it is only exceptionally to be found fossil in rocks deposited at greater depths.” According to Stevenson (1912, p. 518) “the inarticulate brachiopods have changed comparatively little in charac-
ter since their first appearance, and in all probability as little in their habits.” On this fact he based his deductions as to the shallow water origin of the beds overlying coalfields in the Appalachian region where he found Lingula and Orbiculoidea (Discina) in the dark roof shale of the Middle Kittanning Coal Bed of Ohio, and in several of the roof shales in Kentucky.
Schuchert also (op. cit.) found that Lingula has endured since Ordovician times without change other than the superficial ones of form size and ornamentation.
Twenhofel (1926, p. 135) followed Schuchert in regarding Lingula and Discina as characteristic of shallow water from the strand line to about 60 feet. He stated that these two inarticulate forms were known to have lived on a muddy bottom as do some of the lingulids of to-day.
Summarising the significance of the habits of lingulids, Schuchert (op. cit., p. 262) stated, “They are excellent guides as indicators of shore lines, and as such give clear guidance to the palaeogeography of any given time.”
The conclusions that may be drawn from the occurrence of Lingula waikatoensis in the claystone overlying the coal measure series in the Waikato are as follows:—
1. There is clear evidence of the inception of marine or brackish water conditions following the fresh water coal measure claystones. This is confirmed by the stratigraphical succession.
2. The climate was warm-temperate to sub-tropical.
The geological history of this region subsequent to the accumulation of the vegetable debris now forming the coal seams is therefore one of a slowly subsiding land surface, in a large estuary of which fluviatile muds were deposited over the vegetal matter by the inflowing rivers. These muds are characteristically variable both in colour and in consistency and contain leaf remains and irregularly distribtued masses of coalfield vegetable matter. Continued subsidence permitted a transgression of the sea and in the shallow brackish and saline waters which now covered the original fresh water muds the fine sediment carried in by the rivers was more uniform, especially in colour. In this shallow water area, protected from wave action either by a long barrier beach characteristic of subsiding coastal plains or by its situation in a large bay or sheltered gulf, conditions were suitable for the existence of a fauna characterised particularly by lingulids. This fauna is the first evidence of marine conditions in the coal basin of the Lower Waikato district, and if its extent and distribution could be determined the palaeogeography of the land in Middle Tertiary times would be definitely fixed. Continued subsidence resulted in the deposition of the deeper water marine beds of the Whaingaroa and Te Kuiti series.
List of References Cited.
Bittner, A. (1890). “Brachiopoden der Alpinen Trias,” Vienna, 1890.
Blochmann. F. (1892). “Untersuchungen über den Bau der Brachiopoden,” Jena, 1892.
Davidson, T. (1874). “Supplement to the Brit. Tert. Brachiopoda”—“A Monograph on the British Fossil Brachiopoda,” vol. 4, part 1, Palaeontographical Society, London, 1874, pp. 12-13, pl. 2.
Fisher, P. (1887). “Manuel de Conchyliologie,” Paris, 1887.
Grabau, A. W. and Shimer, H. W. (1909). “North American Index Fossils,” New York, vol. 1, 1909, pp. 194-198.
Hall, J. (1847). “Natural History of New York,” part 6, Palaeontology, vol. 1,” 1847.
Hayasaka, I. (1922). “On some Tertiary Brachiopods from Japan,” Sci. Rep. Tokohu Imp. Univ., Ser. 2, Geol. vol. 6, No. 2, 1922.
Henderson, J. (1929). “The late Cretaceous and Tertiary Rocks of New Zealand,” Trans. N.Z. Inst., vol. 60, 1929, pp. 271-299.
Henderson, J. and Grange, L. I. (1926). “The Geology of the Huntly-Kawhia Subdivision,” N.Z. Geol. Survey Bull. 28 (New Series), 1926.
Johnston, T. H. and Hirschfeld, O. S. (1920). “The Lingulidae of the Queensland Coast,” Proc. Roy. Soc. Queensland, vol. 31, 1920, pp. 46-82.
Morse, E. S. (1902). “Observations on Living Brachiopods,” Mem. Boston Soc. Nat. Hist., vol. 1, No. 8, 1902, pp. 313-386, pls. 39-61.
Penseler, W. H. A. (1930). “Fossil Leaves from the Waikato District, with a Description of the Coal Measure Series.” Trans. N.Z. Inst., vol. 61, pp. 451-477.
Reeve, L. (1841). “Conchologia Systematica,” London, 1841.
Schuchert, C. (1911). “Palaeogeographic and Geologic Significance of Recent Brachiopoda,” Bull. Geol. Soc. Amer., vol. 22, 1911, pp. 258-275.
Stevenson, J. J. (1911-12). “The Formation of Coal Beds,” Proc. Amer. Phil. Soc. vol. 50, No. 198, 1911, pp. 1-116, vol. 50, No. 202, 1911, pp. 519-643, vol. 51, No. 207, 1912, pp. 426-553.
Tokunaga, S. (1906). “Fossils from the Environs of Tokyo,” Jour. Coll. Sci. Tokyo, vol. 21, Art. 2, 1906.
Twenhofel, W. H. (1926). “Treatise on Sedimentation,” Balliere, Tindall and Cox, London, 1926.
Thomson, J. A. (1927). “Brachiopod Morphology and Genera (Recent and Tertiary),” N.Z. Board Sci. and Art, Manual No. 7, Wellington, 1927.
Zittel, K. A. von (1900). “Text Book of Palaeontology,” London, 1900, p. 307.
Fossil Leaves from the Waikato District.
With a Description of the Coal Measure Series.
[Read before the Wellington Philosophical Society, 11th June, 1930; received by Editor, 13th June, 1930; issued separately, 18th November, 1930.]
Outline of Stratigraphy.
Coal Measure Series.
Fossils of the Coal Measures.
As a result of mining operations in the Pukemiro Colleries leaf remains were discovered by the writer in the claystone underlying the coal seam, and on subsequent search were found to be fairly commonly distributed in the shaly claystone which in many places forms the roof of the coal. Similar leaves were found in the other mines of the Waikato district. These leaf remains can rarely be observed at outcrops on account of weathering, and they can be obtained in a fresh condition only when, through the necessities of mining, “bottoms have to be lifted,” or the roof “taken down,” or in “stone drives,” etc. Even then the rocks so distrurbed do not invariably contain these fossils. Probably, during the years in which mining operations have been carried on in this district many fossil leaves have been encountered and specimens have been irrecoverably lost through lack of scientific interest on the part of the technical staff of the different colleries.
Assistance in the identifications of the fossil leaves collected was rendered by Mr. W. R. B. Oliver, M.Sc., Director of the Dominion Museum, Wellington, to whom the writer extends his thanks. Palaeobotany in New Zealand has been much neglected and therefore comparisons with other fossil leaves were difficult. In assigning a generic name to a leaf its resemblance to recent leaves was the deciding factor, especially because the leaves were all dicotyledonous.
The writer acknowledges his indebtedness to the Dominion Laboratory, Wellington, for the analyses on p. 460.
The leaves collected by the writer have been lodged with the palaeontological collections of the N.Z. Geological Survey, Wellington.
Hochstetter (1859), when describing the outcrop of coal at Kupakupa on the west bank of the Waikato River near Huntly, referred to the occurrence of fossil plants, principally dicotyledonous leaves, in the shale overlying the coal. He found no ferns accompanying the leaves. In 1864 and 1867 he stated that, of some fossil dicotyledonous leaves found in the coal measures near Drury, the following species had been determined by Unger:—
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Fagus ninnisiana Ung.||F. procera Pöppig from South Chile.|
|Loranthophyllum griselinia Ung.||Loranthus forsterianus Schult., and Griselinia lucida Forst., of the family Cornae, diffused throughout New Zealand.|
|Loranthophyllum dubium Ung.||Loranthus longifolius Deso.|
|Myrtifolium lingua Ung.||No analogy with other fossil leaves of plants of that day.|
|Phyllites purchasi Ung.||Imperfectly preserved: genus indeterminate.|
|Phyllites ficoides Ung.|
|Phyllites novae-zelandiae Ung.|
|Phyllites laurinium Ung.|
Unger (1864) described and illustrated these leaves, of which, however, L. griselinia is from the Bay of Islands and not from Drury. Unger's descriptions and illustrations will be considered later.
Hutton (1867) described the geological section at Kupakupa and found, overlying the coal, four feet of “dark blue shale containing leaves of dicotyledonous plants similar to those of Drury and Nelson.” Later, Hutton (1870) mentioned that there were four or five varieties of these dicotyledonous leaves from Drury and Waikato.
Cox (1877) noted the dicotyledonous leaves in the sandstone roof on the coal seam at Kupakupa.
Park (1886) obtained a small collection of fossil plants from the fireclays at the Taupiri Coal Mine, but gave no description. This collection now forms part of the palaeontological collections of the New Zealand Geological Survey and consists of 18 specimens. On examination by the writer the leaf remains appeared to be similar to those collected and described later in this paper, but the carbonised leaf remains have peeled off the stone and have broken into small pieces so that they cannot now be identified with certainty. All that can be said about the collection is that the leaf remains are mixed with a great amount of fragmentary vegetal matter.
Later, Park (1899) when discussing the coals of New Zealand stated that “the Tertiary coals of New Zealand are the result of forest vegetation of long continued growth, among which dicotyledonous plants are well represented, including oak, myrtle, laurel, cypress, cycads and conifers. Remains of ferns are also abundant.”
Possibly, part of this statement was based on the fossil plants found near Huntly.
Henderson and Grange (1926, p. 49) noted the occurrence of unidentifiable carbonised and fragmentary plant remains in the coal measures.
Excepting Unger's description, therefore, no detailed account of these fossil leaves has been published and their occurrence seems to have been neglected. It was Hector's intention, apparently, to publish an account of the fossil leaves of New Zealand, including those collected by Park, but this intention was never realised, although drawings of them had been made. There are no descriptions of these drawings and it is therefore, in the absence of the specimens, impossible to determine their origin.
Outline of Stratigraphy.
On a gently undulating, planed surface of folded Mesozoic greywackes, argillites, and indurated sandstones, a coal measure series of early Tertiary age was laid down. This series consists of brown and grey claystones, sometimes sandy, and from 80 to 300 feet thick. One to three thick seams of coal, and in places some thin seams, occur near the base of these rocks which are locally known as “fireclays.”
Overlying the Coal Measure Series is the Whaingaroa Series of pale coloured claystone followed by bluish-green calcareous glauconitic sandstone and dark grey calcareous claystone containing a marine fauna. Following this is the Te Kuiti limestone of which only the basal members are present in this district.
The ages of these series are as follows:—
Shingle, sand, clays, etc., and swamp deposits Pleistocene to Recent.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Limestone||Te Kuiti Series|
|Grey claystone||Whaingaroa Series||Ototaran Stage, Oligocene|
|Claystones and Coal,||Coal Measure Series|
|Greywackes, Argillites, etc.||Mesozoic|
Note: The grouping and naming of the individual beds is a result of the writer's investigations, the series and their ages being quoted from Henderson (1929).
Coal Measure Series.
The rocks forming this series are dominantly argillaceous, and, though commonly referred to as fireclays, are better classified as claystones. In places where leaching by organic acids has taken place the claystones approach a true fireclay and are then used for brick-making and pottery work, and for fire brick in gasworks. Analyses of some of these rocks (Henderson and Grange, 1926, pp. 87-90) are given in Table 1.
[Footnote] * See Penseler, 1930b.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Alumina. Al2O3||39.40||29.95||31 80||26.20||24.28||23.87||23.33||22.22|
|Ferric oxide, Fe2O3||1.60||0.98||1.76||2.20||1.60||1.07||2.44||2.20|
|Lime, Ca O||0.20||0.11||nil||nil||0.10||0.09||0.34||0.43|
|Titanium dioxide TiO2||—||0.83||—||—||0.92||1.33||0.92||0.92|
|Combined water and organic matter||16.80||11.99||12.14||12.40||7.76||9.37||9.17||8.29|
|Water at 100°C.||—||8.11||—||—||8.10||*2.08||*2.69||*2.48|
No. 1.—Fireclay, Waikato (probably Huntly, but precise locality not given). Twenty-seventh Ann. Rep. Col. Lab., 1904, p. 11.
No. 2.—Clay from weathered Mesozoic rock. Te Pake Road.
No. 3.—Fireclay, at least 4 ft. thick, below coal, main haulage-way, Taupiri Extended Mine. Fifty-second Ann. Rep. Dom. Lab., 1919, p. 22.
No. 4.—Fireclay, 10 ft. thick, below coal, Rotowaro Mine. Idem.
No. 5.—Fireclay, Waikato Extended Mine. Fifty-fifth Ann. Rep. Dom. Lab., 1922, p. 21.
No. 6.—Fireclay, Pukemiro Junction Mine. Fifty-ninth Ann. Rep. Dom. Lab., 1925, p. 29.
No. 7.—Fireclay, 15 ft. thick, works of Huntly Brick and Tile Company. Fifty-sixth Ann. Rep. Dom. Lab., 1923, p. 17.
No. 8.—Fireclay, below coal, Rotowaro Mine. Fifty-sixth Ann. Rep. Dom. Lab., 1923, p. 18.
The theoretical mineral compositions of the “dry” clays, Nos. 5, 6, 7 and 8 have been calculated as follow:—
|Limonite||1 94||1.28||2.92||2 64|
|Clay substance and combined water||63.09||58.67||58.74||55.22|
The claystones of the Coal Measure Series are often indistinguishable from the weathered argillites on the surface of the underlying unconformable Mesozoic rocks. As shown by some borehole logs the one grades insensibly into the other and it is only when
[Footnote] * Water at 105°.
the basement rock is hard and unweathered (e.g. greywacke).) that the driller can tell with certainty that the “fireclays” have given place to the “understone.”
The Coal Measure Claystones vary in thickness from 80 to 300 feet and contain near their base one to three thick seams of coal and often some minor seams of less extent. The Coal Measure Series is naturally thickest in the deepest portion of the original basin.
The origin of this series as a freshwater estuarine deposit may be stated now instead of as a conclusion. The logical sequence is thus to some extent inverted, but by keeping this conclusion in mind the significance of the features to be described will be realised better.
The main characteristic of the series is its variability both lithologically and in colour. Though in the main argillaceous, sandy patches are encountered grading into normal claystone vertically and laterally. The base of the series is usually sandy, and in some districts, e.g., Glen Afton, contains rounded pebbles of hardened clay, quartz, sandstone, etc., up to 1′ in diameter embedded in fine claystone (Figs. 1 and 2). Coarse conglomerates or gravels are not found. Small, shaly, i.e., laminated, beds are common, but bedding on a large scale is shown only by the succession of beds of different colour, by dark coloured carbonaceous beds grading for a few inches into dirty coal, and by the occurrence of nodular bands of spathic iron ore. In hand specimens the typical claystone shows no bedding or lamination and appears homogeneous. The records of boreholes in the Waikato district show very well the change from place to place of the series, more especially of the beds overlying the coal seam or seams. This change is due to the lenticularity of the different beds in the series.
The colour of the claystones varies from dark grey for the carbonaceous shaly bands through dark brown, brownish-yellow, and light brownish grey to grey. The last named colour predominates and indicates reduction by decaying organic matter of most of the iron compounds, which have been removed in solution. This reduction of iron is due also to moist conditions in a warm temperate or subtropical region with plentiful rainfall where sediments are deposited under water or on damp, ill drained flats (Twenhofel, 1926, p. 547). The layers of fine, brownish-yellow claystone are a result of floods in the estuary when an increased quantity of water carrying yellowish mud in suspension overspread the river flats, scouring out previous deposits in the main channels and depositing the fine yellow muds in the quieter areas.
The claystones weather to a soft, sticky, yellow clay which obscures most outcrops and obliterates differences between successive beds. Underground, contact with mine air causes fretting and spalling off. The joints become loosened and the rock breaks up, and this necessitates timbering in those sections of the mines which have a claystone roof or sides.
During consolidation the sediments settled and shrank and, as the original site of deposition was undulating, differential settling would modify the positions of successive strata, and differential loading would cause an adjustment of the sediments to the pressure
imposed. On a large scale the effects would be variable and would in general induce lenticularity of the strata, but on a small scale the result is comparable with the cleat in the coal. Settling or shrinkage in the claystones, which may amount to 20 to 50 per cent. or more (Twenhofel, 1926, p. 526) results in a large number of small block faults each block rounded more or less vertically by polished faces (Fig. 3). The blocks may be a few inches square and up to a foot or so long—the thickness of the particular bed—or may be, as is more usual, a few feet square. In the former instance, that of a thin layer broken up by many inclined fractures, the effect may be due to compression and differential movement between the beds, and may thus be regarded as a form of fracture cleavage (Leith, 1923, pp. 148-158).
The larger and irregularly spaced joints or “faults” in a thick bed stand in various directions and attitudes. They may intersect, but commonly one joint either dies out before reaching another, or is cut off by another joint crossing it at an angle. Such joints die out vertically or merge into small monoclines. Leith (1923, p. 33), referring to joints related to the contraction of a crystallising and cooling mass of lava, said that “similarly, joints may be very abundant in flat-lying, partially consolidated beds of sediments, which plainly have not been disturbed by great exterior forces. One of the causes in this case is doubtless the change in volume incidental to the drying and settling of the beds. Mud cracks are one manifestation of this process. Joints formed in this manner are likely to be limited to particular beds and may die out above or below; there may be evidence that jointing in a given bed was complete before the next layer of sediment was deposited. They are likely to be especially abundant near the contacts of different beds or formations (a fact often noted by well-drillers in search of water).” This type of local tensional jointing he said (op. cit., p. 50) “is developed by the drying out of a sediment, resulting in the formation of mud cracks and of shrinkage cracks on a large scale. The joints so formed lack regularity and persistence, vertically and horizontally.”
It is evident therefore that the irregular jointing observed in the coal measure claystones is a result of the settling and shrinkage, including effects due to slumping in the original sediments.
The blocky nature of the claystones, combined with their property of flaking and loosening on exposure to the damp mine air, is a source of danger underground. A claystone roof is incapable of supporting itself and requires timbering.
The bands of iron ore are commonly in the form of nodules irregularly spaced and often up to 4 feet thick. They occur below, between and above the different seams and are the result of precipitation of iron from iron bearing solutions in the presence of decaying organic matter which, by providing excess of CO2, causes precipitation in the form of carbonate. Twenhofel (1926, p. 331) considers that iron sediments are deposited usually in quiet waters, e.g., bogs, marshes, lakes, lagoons, and the sea, and are also precipitated where iron bearing solutions issue from the ground.
Similar views are held also by Clarke (1924, pp. 536-538). With regard to the concretionary type the iron may be brought in as ferrous bicarbonate solution from which, on escape of excess CO2 and under conditions which do not allow of its replacement by oxygen, iron carbonate is precipitated (Twenhofel, op. cit.). Such conditions, according to this authority, obtain in marshes, shallow waters of the sea, lake coasts, and river flood plains where the growing vegetation extracts the CO2 from the water and the decay of vegetation uses up the oxygen. Further, any iron precipitated as hydroxide might be altered to the carbonate by decaying organic matter. The presence of these concretionary masses of iron ore in the Coal Measure Series indicates, therefore, shallow water conditions such as would obtain in river flats in an estuary where the iron leached from the clays and sediments is precipitated on reaching the surface. There must have been excess CO2 present from the abundant decaying vegetal matter in these sediments to prevent precipitation in the form of hydrated oxide. The iron ore bands occur at no definite horizon, but though horizontally bedded are irregularly spaced, and were therefore determined by local conditions at each place. An analysis of one sample is as follows: (from 56th Ann. Rep. Dom. Lab., N.Z., 1923, p. 24, quoted by Henderson and Grange, 1926, p. 96).
|Water lost at 105°C.||2.12|
|Water lost above 105°C.||0.56|
As shown by this analysis the deposits are impure, as would be expected where sedimentary material is abundant.
Fossils of the Coal Measures.
A fossil fauna is absent.
Lumps of fossil resin similar to those occurring in the coal and named Ambrite by Hochstetter (1867) are common in the claystone (see Fig. 4). They have been observed so far only in the vicinity of the coal seam or seams, but this may possibly be owing to the lack of facilities for examining the remainder of the series. Hochstetter's (1867, p. 79) description is still applicable, and according to him the resin is transparent, brittle, and has a
glossy conchoidal fracture. In colour it is bright yellow to dark brown. It is easily ignited and burns with a steady fast-sooting flame with a bituminous rather than aromatic smell. He thought that the resin originated from a confierous tree related to the present Kauri pine, and gave the following analysis:—
which is equivalent to the formula C8 H13 O.
Its hardness was 2, and specific gravity 1.034.
Analyses of other fossil resins with which this is comparable are given by Moore (1922, pp. 102-104), and the amber mined from Tertiary rocks on the shore of the Baltic Sea in East Prussia is described by Prockat (1930).
The low specific gravity of the resin would enable it to be readily transported by even slight currents, but any argument based on its present properties is unsafe because of the alteration it has undergone by hardening, loss of volatile matter, etc., since it was deposited. When a lump of resin occurs in a shaly layer the laminae are bent round it and it seems reasonable to suppose that it was drifted into secluded backwaters where it became entombed by the covering muds. Where the current was stronger the resin would be carried out to sea.
The resin in the claystones and that in the coal differ in origin to the extent that the former was allochthonous and the latter autochthonous, although both might have been derived from the same species of tree.
On exposure to the weather the resin becomes opaque and waxy looking.
The presence of the resin may be taken as evidence of the occurrence of coniferous trees in the flora of that time.
Fragmentary coalified plant remains (see Figs. 5 and 6) are of common occurrence and vary in size from small pieces, which represent twigs, up to large masses 6 feet or more long and 2 feet broad. The larger remains are usually more or less flattened and all have a black colour and a shining lustre. Smaller branching remains resembling roots also occur, and what appears to be a coalified fungus is shown in Fig. 7. One fragment had the “bark” still adhering (Fig. 8). These coalified plant remains are homogeneous, i.e., not laminated like the coal, and on account of their friability only small portions can be preserved as specimens. They occur in any part of the claystones and often are embedded partly in one variety of “fireclay' and partly in another. They represent fragments of plants that have been drifted in by the rivers which deposited the muds around them when they became stranded. Their analogy with the strips of “bright coal” in the seam (see Penseler, 1930a) is shown by the following analyses:—
|Bright Coal||Coalified fragment in fireclay above seam||Coalified fragment in fireclay below seam||Normal Coal|
|Ash||1.05||4.26||2 34||2 56|
|B. Th. U.||9950||9734||9939||10802|
|On a dry ash-free basis:|
|B. Th. U.||13090||12600||12820||13160|
It will be seen from these analyses that the coalified remains are similar in analysis to the bright coal and are higher in water and fixed carbon and lower in volatile matter than normal coal.
The bright strips in the coal represent unmacerated fragments of wood in the original vegetable mass, and because the coalified remains found in the claystones are clearly derived from fragments of wood the above results were therefore to be expected. The point of interest, however, is that the wood in the form of logs buried in the clays has in the course of time been changed into “coal” similar to that formed from the remains of small pieces of wood in the peaty deposit now forming the coal seam proper. The latter are what was left when the general process of maceration and bacterial decay was suppressed by the smothering action of overlying material and by the probable development of toxic conditions in the peaty mass, and it may be concluded that the logs buried in the fireclays had not been subjected to any process involving maceration but had undergone bacterial decay. Heat and pressure in addition were responsible for the change from wood to coalified material.
Where the normal claystone changes to a laminated shaly clay, dark grey in colour, it often includes very thin streaks of bright coaly matter and on splitting these dark coloured laminated clays leaf remains are found. After splitting a fragment of shale containing a leaf, apparently two leaves are obtained due to separation of the leaf along the centre of the lamina. The state of preservation of the leaves depends on several factors. If the enclosing material is at all coarse grained (comparatively speaking) the leaves may be broken and fragmental, or impressions only may be left owing to opportunities for access of air and water. If the shale during the extensive shrinking which occurred in the coal and in the muds
was subjected to pressure resulting in lateral movement the surfaces and outlines of the leaves are blurred. It is only when the enclosing material is sufficiently fine grained and has not been distorted that favourable conditions obtain. Another important point is that leaves which have been transported by muddy water for some distance become bruised, torn, and fragmental, but those deposited in sheltered backwaters after very little transportation are more likely to be preserved whole. Fragmental leaves are often associated with much general vegetal debris such as portions of bark, broken twigs, branches, etc., as in Park's collection referred to previously.
The best preserved specimens were obtained from a dark grey shaly layer, a few inches thick, occurring in a light grey, rather sandy claystone about 6 feet below the base of the coal seam in the West Drive of the Pukemiro Colliery. The leaves, though not perfectly preserved in all detail, are much better than those collected at other places. They are all black in colour and occur horizontally bedded in this thin layer. Less well preserved and poorly preserved leaves were found in many places where a dark grey, shaly clay forms the roof of the coal seam, but in most instances prolonged contact with the mine air had caused the leaves to peel and scale off. This property of scaling has to be guarded against in specimens, which also have a marked tendency to break up into small rectangular pieces by a series of fine joints at right angles to each other.
On account of the weathering of the claystones into a sticky yellow clay, outcrops of the Coal Measure Series are disappointing to the collector. Any contained plant remains are usually broken up or obliterated, and even in sandy and shaly beds, which weather differently, plant remains quickly disintegrate.
The fossil leaves thus differ from the fragments of fossil “wood” described before in that the former are bedded and the latter irregularly distributed. No leaves have been observed joined to twigs in the form of sprays, and no leaves have been observed in conjunction with the masses of coalified wood.
Cinnamomum waikatoensis n. sp. Figs. 9 to 13, and 41.
Holotype: Figs. 12 and 41.
Leaf oblong-elliptic, the apex slightly more acute than the base. Margin entire. Midrib well marked; secondaries alternate or sub-opposite, 6 to 8 on either side of the midrib, arising at regular intervals at an angle of about 45° and gently curving forwards and becoming obsolete near the margin; they are prominent and almost parallel. Tertiary veins, shown on Fig. 10, branch towards the margin, arising from the secondary veins at an angle of about 60° and curving forwards. On this specimen also a pair of small veins, probably tertiary, are seen near the base of the leaf.
Figs. 12, 13.—Cinnamomum waikatoensis n. sp. × 1. From Coal Measure Claystones, Pukemiro Colliery.
Figs. 14, 15.—Cassia pluvialis n. sp. × 1. From Coal Measure Claystones, Renown Colliery, Waikokowai.
Fig. 16.—Fagus ninnisiana Ung., × 1. From Coal Measure Claystones, Pukemiro Colliery. [W.H.A.P., del.
This is the most commonly occurring leaf observed by the writer. It has been placed in the genus Cinnamomum because of the occurrence of two well marked opposite secondary veins at the base; and in order to give some means of identification to the leaf the specific name “waikatoensis” has been assigned to it. No form resembling this was collected by Hochstetter or described by Unger, and it has been impossible to find definite relationships with any modern genus in New Zealand. (Cf. C. intermedium, Ettingshausen, 1887, Taf. 4, Fig. 20).
Leaf elliptic, widest in the middle and tapering towards either end. Base acute, apex produced into a rounded protuberance or drip point. Margin entire; midrib prominent. Secondary venation not observable.
No leaf like this has been found among the living New Zealand flora, but it bears some resemblance to C. pseudophaseolites (Ettingshausen, 1887, Taf. 4, Fig. 6) from Shag Point and Murderer's Creek, the apices of which are missing or turned over and buried in the rock. The apices of C. pluvialis were bent over into the claystone and were discovered only by carefully picking out the covering rock.
A fragment without either base or apex, and showing a portion of one side only. Leaf apparently broadly elliptical. Margin serrate. Secondary veins arise regularly from midrib at an angle of about 60°, and terminate in the indentations within the marginal teeth.
Distance from midrib to margin, 19 mm.
Estimated size of leaf, 72 × 38 mm.
This leaf is similar to those collected by Hochstetter from beds of about the same age at Drury and classed as F. ninnisiana by Unger (Figs. 24–32), and for the want of better specimens has been taken as belonging to the same species.
Unger compared F. ninnisiana with F. obliqua Mirb. and with F. procera Pöpp., recent species from Chile, which vary not only in size and shape but also in the marginal teeth exactly as do the fossil leaves. The longer petiole in the fossil leaves (Figs. 24 and 25) may be due to especially strong root force, although in other cases (Figs. 28 and 31) the size is not abnormal.
“It is remarkable that a plant form with its related kinds, which occurs in South Chile, Patagonia, Tasmania, and New Zealand, appears also in the Tertiary flora of these countries as well as in the Tertiary flora of the Northern Hemisphere. This may be an indication that the stock of Fagus originated in and spread readily from the Southern Hemisphere. What is particularly remarkable is that the large leaved kinds of this genus, with the folded bud
position of the leaves, as also the small leaved kinds with mostly leather-like leaves, are represented in the Tertiary flora, while New Zealand at present possesses only the latter kind.” F. ninnisiana occurs also at Shag Point, Otago, and was described by Ettingshausen (1887, p. 24, and Taf. 4, Fig. 1; 1890, p. 270, and Pl. 27, Fig. 1).
Beilschmiedia tarairoides, n. sp. Figs. 17 to 19, and 43.
Holotype: Figs. 19 and 43.
Leaf broadly elliptic, margin entire. Midrib broad, prominent and prolonged into a thick petiole. Secondaries alternate or subopposite, arising at rather wide intervals at an angle of about 50° and arching forwards. They terminate near the margin and nearly parallel to it, and sometimes bifurcate at their extremities. Tertiary veins cross between the secondaries and nearly at right angles to them.
Breadth of largest leaf (Fig. 19) is 65 mm. The most similar leaf among the existing New Zealand flora is that of Beilschmiedia tarairi, and accordingly the fossil form has been given the specific name tarairoides.
A fragment of a large leaf without either base or apex. Leaf oblong elliptic. Margin imperfectly preserved, but apparently entire. Midrib well marked, and in this specimen, which shows the under surface of the leaf, is characteristically ribbed longitudinally. Secondary veins branch from the midrib at irregular intervals and are not always parallel. They leave the midrib at an acute angle but soon bend round to an angle of 65° to 70° and near the margin curve forwards again. Tertiary venation not observable. Maximum width of leaf 68 mm.
Unger (1864, p. 11) described a small fragment (Fig. 36) of a large leaf under the name Phyllites purchasi, which could not be compared with leaves of living or fossil plants. Comparison of
Figs. 20 and 36 shows that these fragments are probably of the same kind. Moreover, the larger fragment collected by the writer is almost identical with leaves of the recent Pisonia brwnoniana now living in North Auckland. The fossil leaves are accordingly placed in this genus and Unger's specific name retained.
Pisonia oliveri n. sp. Figs. 21 and 42, Holotype.
A fragment of a large leaf without base and apex. Leaf oblong elliptic, the apex probably slightly more acute than the base. Margin widely crenate. Midrib well marked. Secondaries alternate, parellel, branching from midrib at an angle of about 65° and sometimes bifurcating once and occasionally twice near the margin.
Fig. 22.—Coprosma pseudoretusa n. sp. × 1.
Fig. 23.—Geniostoma apiculata n. sp. × 1. From Coal Measure Claystones, Pukemiro Colliery. [W.H.A.P., del.
Estimated dimensions, 255 × 112 mm.
This leaf differs specifically from P. purchasi (Ung.) in the secondary venation and in the margin but it still has strong affinities with the genus Pisonia.
Coprosma pseudoretusa n. sp. Fig. 22, Holotype.
Leaf obovate. Margin entire. Secondary veins are alternate, straight and parallel, and branch from midrib at an angle of 45° to
50°. They anastomose near the margin and the tertiary venation, which is partly preserved, probably consists of a coarse network joining the secondaries. Dimensions, 75 × 34 mm. This leaf is very similar to the recent C. retusa.
Geniostoma apiculata n. sp. Fig. 23, Holotype.
Leaf oblong elliptic; apex produced into a blunt point. Margin entire. Midrib and secondary veins well marked, the latter alternate, parallel and curving regularly forwards. The tertiary venation on this leaf is remarkably well preserved and consists of a fine network into which the ends of the secondary veins merge.
Dimensions, 95 (estimated) × 39 mm.
The following leaves collected by Hochstetter, were not found by the writer in the Coal Measure Series of the Waikato district, but their occurrence near Drury in beds of approximately the same age justifies their mention in this paper. Most of the leaves are so fragmental that comparison with existing forms would be without benefit because of the probable inaccuracy involved.
Loranthophyllum dubium Ung. Figs. 33 and 34.
This leaf was named from its similarity to L. griselinia Ung. (1864, pp. 8-9, Taf. 3, Fig. 13) and to Loranthus longifolius Deso. A remnant of a stem (Fig. 31) from the same locality shows the original opposite positions of the leaves and the protruding leaf cushions such as occur also on the stem of L. longifolius (Fig. 32).
Myrtifolium lingua Ung. Fig. 37.
Unger found no resemblance to this well preserved leaf among either fossil or living forms. There is no known living form similar to this in New Zealand.
Phyllites laurinium Ung. Fig. 38.
This leaf scrap bears some resemblance to Laurum princeps, “but that does not in the slightest degree mean its complete accord.”
Phyllites ficoides Ung. Fig. 39.
This was compared doubtfully with the leaves of some kinds of Ficus. (A smaller fragment from the Pukemiro Mine appears to be from the same kind of leaf).
Phyllites novae-zelandiae Ung. Fig. 40.
Unger found no similarity of this leaf with leaves of New Zealand trees and obtained no true identification with other living or fossil leaves.
These dicotyledonous leaves belong to forest trees and shrubs the modern representatives of which are confined to warm temperate or subtropical regions. They have a general Malayan character. An attempt to determine the probable plant associations from this small collection would be unwise. If more types are in the future discovered it may then be possible to reconstruct the flora which contributed the vegetable debris now constituting the coal seams of the district, although fossil leaves are but poor material for botanical
classification. At present the only safe conclusions are those concerning the climate and the predominantly angiospermous nature of the flora.
The latter characteristic is of great importance because it influences the nature of the peat formed from this type of vege-
tation, and hence that of the resulting coal. From the leaf remains collected by the writer, and also by Hochstetter and others, it can be deduced that the swamp was of the wooded or forested type in which angiosperms were the dominant form, though conifers were
Figs 33, 34.—Loranthophyllum dubium Ung. × 1. (33.) Piece of leaf. (34.) Piece of a twig with strongly protruding leaf cushions. From Mr. Fallwell's place near Drury, in a light grey, greasy claystone.
Fig. 35.—Loranthus longifolius Sprgl. × 1. Piece of twig for comparison with Fig. 34.
Fig. 36.—Phyllites purchasi Ung. × 1. From Mr. Fallwell's place near Drury, in a light grey, greasy claystone. [After Unger.
present in subordinate amount as evidenced by the occurrence of resin. According to Thiessen (1928, p. 38), “Peat formed from the wooded swamp is of particular interest because it appears to be analogous to most of the bituminous coals and to many lignites
Fig. 37.—Myrtifolium lingua Ung. × 1.
Fig. 38.—Phyllites laurinium Ung. × 1.
Fig. 39.—Phyllites ficoides Ung. × 1. These are from Mr. Pollock's Spring Hill Shaft near Drury, in a firm ferruginous sandstone.
Fig. 40.—Phyllites novae zelandiae Ung. × 1. From Mr. Fallwell's place near Drury, in light grey, greasy claystone. [After Unger.
and sub-bituminous coals. Each peat deposit that results from the different types has a distinct character. The greatest distinction is to be found in peat derived from angiosperms (the ordinary leafy trees) and that from conifers.” He states further that “the angiosperms yielded readily to decay and disintegration, leaving little more than an amorphous muck or attritus; the conifers, on the other hand, wherever present, resisted decay and maceration to a far greater extent, due to their toxic resinous contents, and left a large proportion of better-preserved woody material.” Coals derived from a coniferous flora are therefore always woody, whereas those derived from an angiospermous flora are always more or less amorphous. The two types are readily distinguished.
The coal from the Waikato district has the amorphous appearance described by Thiessen. It consists mainly of a relatively dull matrix in which are embedded small strips of bright coal (the “anthraxylon” of Thiessen) though in small amount only. Rarely are large strips of bright coal seen (see Penseler, 1930a).
The reason for the present characteristics of the Waikato coal is thus clear. Its origin in a freshwater wooded swamp from a predominantly angiospermous flora is evident from the palaeobotany and the geological history of the Coal Measure Series. From this type of flora, a characteristically Tertiary one, coal of a special nature is to be expected, and this expectation is confirmed by an examination of the Waikato coal.
During and after the planation of the Mesozoic rocks a large estuary occupied the site of the present Lower Waikato Basin. Rivers flowing into this estuary carried the products of weathering of the low lying surrounding country which, owing to the moist subtropical climate, was thickly covered with vegetation. The sediments deposited on the estuarine flats consisted therefore mainly of fine decomposed, rather than disintegrated, rock material. Organic acids leached out or reduced most of the iron compounds to a soluble state, resulting in grey or brownish grey colours. The sediments were deposited irregularly owing to the swinging of the rivers from side to side, and owing to the probable braided estuarine channels; and the gradual subsidence of the land permitted the continual building up of the sediments. Differences in the strength of the currents caused by seasonal changes in rainfall and by floods of greater or less magnitude caused differences in the nature, thickness, and colour of the sediments, and further irregularities were caused by the scouring out of previously deposited material, the by-passing of fine material, and the deposition of coarser material (see Eaton, 1929). Differential settling on an originally undulatory surface caused subsequent deposits to be not parallel, and because each successive surface of deposition would be irregular and not necessarily parallel to the preceding surface general uneveness and lenticularity of the beds was developed.
Because a subsiding land surface does not subside at an even rate, “hesitations” of longer or shorter duration occurred, and during these periods the elevation of the land remained either constant in elevation or subsided much more slowly than the average rate. At such a time then the sediments in the estuary were built up to a profile of equilibrium proper to the conditions, after which no sediment was deposited until the base level of deposition or profile of equilibrium was lowered either by the scouring out of some of the accumulated sediments during a flood, or by renewed or increased subsidence of the land. Thus there occurred periods in the history of this estuary during which the land was relatively stable, when the sediments had been built up to a profile of equilibrium, and when shallow water prevailed over a large portion of the estuary. The filling in of the dips and hollows in the old land surface by the sediments formed a broad low-lying swampy district. Conditions were then favourable for the luxuriant growth of vegetation and the accumulation of a vast quantity of vegetal matter on these swampy lands, and the extent to which it accumulated depended on the duration of the period of hesitation in subsidence. It was necessary for the inception of growth of this vegetation that the district should be above water-level for a period, but it was necessary for the accumulation of vegetal matter that a slow subsidence should be taking place fast enough to allow the peaty matter to grow and be always more or less covered with water, but not so fast that accumulation could not keep pace with subsidence. If that rate was exceeded then the vegetation was killed and the peat mass covered by muds and clays deposited to be built up to a new profile of equilibrium.
The writer does not propose here to discuss the processes and reactions taking place in the vegetal matter to form this kind of coal, and the presence of coal seams in the Coal Measure Series is considered only in the light of an event in the history of this series.
A longer or shorter period of hesitation determined the nature and thickness of the vegetal matter—a long period resulted in a seam of coal and a short period in a layer of impure coal or carbonaceous matter—but these accumulations would not be found over the whole estuary. Their occurrence, more particularly for the smaller masses, is controlled by favourable local conditions, although for a thick seam of coal it is evident that widespread favourable circumstances must have existed.
The nodules of bog iron ore were formed during some of these periods of hesitation, and may be seen forming to-day under similar conditions.
During flood times logs, branches, and general debris were washed down by the rivers. The majority of these were undoubtedly carried out to sea where they were destroyed by the scavenging animals present and by general decay. Some of the logs, however, were washed over the shallow river flats inundated by the flood and here, becoming water-logged or sticking in the muds
and clays, they were left when the flood subsided, partly or completely buried in sediment. Subsequently deposited sediment may be different in colour and texture, and in the Pukemiro Collieries some of these old fragments were seen lying at an angle to the bedding of the claystones embedded partly in one kind and partly in another kind of rock. The majority of this debris was carried some distance because the fragments are stripped bare of bark, twigs, leaves, etc. In one instance only was the “bark” still present (Fig. 8).
In periods of flood, leaves and twigs were broken up or carried out to sea. As previously noted, leaves are found in thin bedded layers which can be accounted for only by supposing that they were drifted into sheltered waters where, becoming waterlogged, they sank to the bottom and were thus deposited with the fine mud and fine carbonaceous debris to form a thin laminated layer. The state of perfection of the leaves at the time of burial depended on the distance to which they had been transported and the conditions to which they had been subjected. The roof of the coal seam in many places contains leaf remains, as would be expected because in the calm shallow waters which gradually extended over the buried vegetal matter conditions were favourable for the preservation of leaves in the fine sediments deposited from the overspreading muddy waters.
Taking into consideration the many factors and combinations of factors which could influence the deposition of sediments (including vegetal matter) in the estuary, the cause of the variations in the Coal Measure Series becomes apparent, and, conversely, these variations can be explained only by reason of their depositions in an estuary under the conditions outlined.
After the Coal Measure Series was deposited, continued subsidence of the land permitted a transgression of the sea (see Penseler 1930b), and during the first stage of the succeeding Whaingaroa Series shallow brackish water covered the site of the estuary and initiated the overlying series of marine sediments.
List of References Cited in Text.
Clarke, F. W. (1924). “The Data of Geochemistry” U.S. Geol. Survey, Bull. 770, 5th ed. 1924.
Cox, S. H. (1877). “Report on Raglan and Waikato Districts.” Rep. Geol. Explor. during 1874-76, N.Z. Geol. Surv. Rep., vol. 9, 1877, pp. 9-16.
Eaton, J. E. (1929). “The By-Passing and Discontinuous Deposition of Sedimentary Materials.” Bull. Amer. Assoc. Petr. Geol. vol. 13. No. 7, 1929, pp. 713-762.
Ettingshausen, C. von (1887). “Beiträge zur Kentniss der Fossilien Flora Neuseelands.” Vienna, 1887.
—— (1890). “Contributions to the Knowledge of the Fossil Flora of New Zealand.” Trans. N.Z. Inst., vol. 23, 1890, pp. 237-310.
Henderson, J. (1929). “The Late Cretaceous and Tertiary Rocks of New Zealand.” Trans. N.Z. Inst., vol. 60, 1929, pp. 271-299.
Henderson, J. and Grange, L. I. (1926). “The Geology of the Huntly-Kawhia Subdivision.” N.Z. Geol. Survey, Bull. 28 (new series), 1926.
Hochstetter, F. von (1859). “Lecture on the Geology of the Province of Auckland.”
—— (1864). “Geologie von Neu Seeland; Beiträge zur Geologie der Provinzen Auckland und Nelson” Novara-Expedition, Geologischer Theil, 1. Band, 1. Abtheilung. Vienna, 1864.
—— (1867). “New Zealand,” English Ed., 1867.
Hutton, F. W. (1867). “Geological Report on the Lower Waikato District. N.Z. Geol. Survey Reps., vol. 2, 1867.
—— (1870). “On the Relative Ages of the Waitemata Series and the Brown Coal Series of Drury and Waikato.” Trans. N.Z. Inst., vol. 3, 1870, pp. 244-49.
Leith, C. K. (1923). “Structural Geology.” Revised Ed., Henry Holt and Co., New York, 1923.
Moore, E. S. (1922). “Coal.” John Wiley and Sons Inc., New York, 1922, pp. 102-104.
Park, James (1886). “Report on Huntly-Raglan District.” Reps. Geol. Explor. during 1885, NZ. Geol. Survey Reps., vol. 17, 1886, pp. 141-147.
—— (1899). “Notes on the Coalfields of New Zealand.” N.Z. Mines Record, vol. 3, No. 9, 1899, pp. 349-352.
Penseler, W. H. A. (1930a). “The Classification of the Waikato Type of Coal.” N.Z. Dept. Sci. Ind. Res., Bull., 24, 1930.
—— (1930b). “A Lingulid from the Tertiary Rocks of the Waikato District.” Trans. N.Z. Inst., vol. 61, 1930, pp. 441-451.
Prockat, F. (1930). “Amber Mining in Germany,” Engineering and Mining World, vol. 1, No. 3, 1930, pp. 150-152.
Thiessen, Reinhardt (1928). “Classification of Coal, from the viewpoint of the Palaeobotanist.” Classification of Coal, Amer. Inst. Min. Met. Eng., Tech. Publ., No. 156, 1928, pp. 28-44.
Twenhofel, W. H. (1926). “Treatise on Sedimentation.” Ballière, Tindall, and Cox, London, 1926.
Unger, F. (1864). “Fossile Pflanzenreste aus Neu-Seeland.” Palaeontologie von Neu-Seeland, Novara-Expedition, Geologischer Theil, 1. Band, 2. Abtheilung, Vienna, 1864.
On the New Zealand Lamprey, Geotria australis, Gray.
Part 2.—On the Mid-gut Diverticula, the Bile-duct, and the Problem of the Pancreas in the Ammocoetes Stage.
[Issued separately, 25th November, 1930.]
Northern Hemisphere Ammocoetes.
Ammocoetes of Geotria.
Although some observers have had at their disposal a few specimens of the Ammocoetes stage of Geotria—Kner (1869), Smitt (1901), Plate (1902), Dendy (1902)—not one, so far as I can find, has examined the internal anatomy of this interesting form. Smitt (1901) has remarked on its external similarity to the European Ammocoetes, from which, however, it differs in the greater number of pre-anal myomeres. What was my surprise to find, on dissection, and on examination of serial sections, that at the junction of oesophagus and mid-gut, there are constantly present two forwardly directed diverticula, a right and a left! The right is comparatively short and blind, the left is quite long, about half as long as the oesophagus, and into it upon its dorsal surface and near its anterior end opens the bileduct. Below will be given, first, an account of the relations which the bile-duct exhibits in the Northern hemisphere Ammocoetes, and, secondly, will be described and figured the relations of bile-duct and diverticula as observed in the Ammocoetes of the Southern hemisphere lamprey, Geotria. It will be noted that the diverticula are lacking
[Footnote] * During the course of this work, I attempted to extract insulin from the insular organ (Cotronei) of Geotria australis, but without success. Professor J. J. R. Macleod, of Aberdeen University, kindly suggested the method of extraction, which was followed and Dr. Lynch, of the Wellington Hospital, tested the extract on mice. The mice appeared perfectly well after the injection and showed none of the expected symptoms. Only six lampreys were available for the experiment and the insular organ is very small, so the amount of material to work with was also very small. So far as I know, then, physiological evidence of the presence of insulin in this organ is still lacking.
in Northern hemisphere Ammocoetes, and this is the first time, to my knowledge, that they have been observed and described in the Ammocoetes of Geotria.
I take this opportunity of expressing my thanks to Mr. Kevin Rix-Trott for assistance in collecting Ammocoetes, to Mr. A. Waterworth for the micro-photographs, and to Professor H. B. Kirk for criticism and advice.
2. Northern Hemisphere Ammocoetes.
Brief mention of the bile-duct in these forms is made by Langerhans (1873, p. 41), Schneider (1879, p. 90), and Goette (1890, p. 75). Fig. 1 is copied from Fig. 140 of Goette, representing a dorsal view of the heart-liver region of a larval stage (neither age nor length stated) of P. fluviatilis. As text-books rarely describe the anatomy of the Ammocoetes, the following brief account of the bile-duct (Nestler) is given.
Nestler ((1890, p. 107) says “Beginnen wir die Beschreibung bei Ammocoetes. Eine sehr grosse und weite, von ganz niedrigem Cylinderepithel ausgekleidete Gallenblase liegt in der vorderen rechten Leberhälfte. Aus ihr kommt der Gallengang hervor. Nachdem sich die Arteria coeliaca zu ihm gesellt hat, ziehen beide, zu einem gemeinsamen Strang vereint, schräg rückwärts über den Magen hinweg auf dessen linke Seite. Hier, fast am Leberende, mündet der Gallengang in den Anfangsteil des Mitteldarmes, während die Coeliaca in die Darmfalte eintritt.”
Further I have examined an Ammocoetes (length—10.5 cms.) of Entosphenus appendix, from Maple River, Cheboygan County, Michigan, U.S.A. For this specimen I am indebted to Professor Carl Hubbs of Michigan University. Here the bile-duct leaves the liver about half-way down its length, runs parallel with the coeliac artery, and both in a common strand run obliquely backwards, crossing dorsally the oesophagus and entering the mid-gut on the left dorsal side at the junction of oesophagus and mid-gut.
The above figure and descriptions will suffice to show conditions as they are found in European Ammocoetes (Petromyzon) and N. American Ammocoetes (Entosphenus appendix).
3. Ammocoetes of Geotria.
A dissection from the dorsal surface, which requires the removal of nerve-cord, notochord, aorta, kidneys and fat bodies, exposes the diverticula and the bile-duct. The conditions exposed are essentially similar in Ammocoetes of 1.1 cm. length, the smallest I have yet found, and in larger specimens, till metamorphosis sets in. Metamorphosis occurs usually at a length of about 10 cms. At metamorphosis both diverticula disappear, as well as gall-bladder and bileduct. Figs. 2 and 3 are drawn to illustrate conditions as found in Ammocoetes respectively of 2.8 and 9 cm. length.
At the junction of oesophagus and mid-gut (intestine) two forwardly-projecting diverticula, a right and a left, are given off. The right is comparatively short, extends forwards only a short way below the posterior tip of the liver and ends blindly. The left diverticulum is much longer and runs forward parallel to the oesophagus. Before it ends blindly, the bile-duct opens into it on its dorsal surface. The bile-duct leaves the liver about the middle of its length, crosses the oesophagus and debouches into the dorsal surface of the left diverticulum. Though it is correct to speak of right and left diverticula, at the junction of oesophagus, diverticula and midgut, the oesophagus is rather more dorsally situated than the two diverticula, which lie one on either side of it and at a slightly lower level, i.e. more ventrally. (Fig. 8).
In an Ammocoetes of 4 cm. length, the left diverticulum measured 2.5 mm. long, the right 0.5 mm., in a specimen of 7.5 cm. length, the left 5 mm., the right 1 mm.
The liver is found immediately behind the heart region. Its ventral surface is convex, its left dorsal surface slightly concave, the oesophagus and left diverticulum resting in this concavity. (Fig. 10).
On the right side it attains its greatest development. It is broadest anteriorly, posteriorly it tapers to a point on the right side, where the portal vein enters. The anterior surface of the liver is slightly concave and fused with the posterior wall of the sinus venous. A median ventral ligament binds the liver to the ventral body wall—this, however, is quite short and developed only in the anterior region of the liver.
The gall-bladder is located in the right anterior portion of the liver. In small Ammocoetes, it is relatively immense (Fig. 2), and occupies about half the volume of the liver. In such a specimen it is largely naked, i.e. not clothed by liver tissue. But as the liver grows, the gall-bladder does not keep pace with it and in a 9 cm. Ammocoetes it is, relatively to the liver, quite small. (Fig. 3). In
Figs. 2a and 2b.—These represent dorsal and ventral views of dissections of the liver-region of Ammocoetes of Geotria. The scale on Fig. 2a applies to all. In all figures a = dorsal view, b = ventral view. Figs. 2a and 2b. Ammocoetes 2.8 cm. Lettering as in Fig. 3.
the smaller specimens (up to about 5 cms.) the epithelium lining it is very thin and flattened, in the larger specimens it is cubical to cylindrical.
The bile-duct enters the dorsal surface of the left diverticulum near the anterior end of the latter. From here we may trace it back over the oesophagus, which it crosses dorsally in the same strand of tissue as the mesenteric (coeliac) artery, to the liver. In small Ammocoetes it crosses the oesophagus transversely, in larger ones usually obliquely. (Figs. 2 and 3). On reaching the liver, it may be followed a short distance posteriorly before it is lost to the eye in the liver tissue.
The ventral hepatic vein with several tributaries may be observed easily on the ventral surface of the liver. (Fig. 3). It discharges into the posterior ventral region of the sinus venosus. On the right dorsal surface of the liver, close to the gall-bladder, is a much smaller
dorsal hepatic vein, which discharges into the sinus venosus. This vein runs close alongside the mesenteric artery in its short course. It is not shown in the figures.
Anteriorly, the gut-vein runs dorsal to the gut on the side opposite to the spiral fold. A short distance behind the junction of oesophagus, diverticula and mid-gut, it receives a large branch from the dorsal wall of the mid-gut. This branch is made up of veins from
Figs. 3a and 3b.—Ammocoetes 9 cm. The liver is stippled, the gall-bladder clear and the bile-duct black. OES, oesophagus; AM, mesenteric artery; GB, gall-bladder; L.DIV and R.DIV, left and right diverticula; PV, portal vein; INT, mid-gut; SF, spiral fold; BD, bile-duct; VHV, ventral hepatic vein.
both diverticula, and a vein from the spiral fold. Otherwise for some distance immediately posterior to the liver it lies free from the gut. After receiving this branch, it continues forward as the hepatic portal vein to the tip of the liver which it enters. It may then be followed for a short distance along the dorsal surface of the liver, in which organ it breaks up. (Figs. 2 and 3).
The mesenteric artery (coeliac, coeliaco-mesenteric) is given off from the right side, more dorsally than ventrally, of the dorsal aorta at the level of the venous confluent. It courses to the right, obliquely outwards and backwards, through the venous confluent, which it now leaves. It then bends ventrally and runs obliquely inwards and backwards, and along the dorsal surface of the liver to which it is attached. Its course is now more or less parallel with the oesophagus. When it reaches the bile-duct, in the same strand of tissue, it crosses the oesophagus dorsally, then leaves the bile-duct which enters the dorsal surface of the left diverticulum, and now runs along the inner (i.e. right) side of the left diverticulum to the junction of diverticula and oesophagus with mid-gut. Here it enters the spiral fold as artery of the spiral fold or intraintestinal artery.
Fig. 4.—Ammocoetes, 1.2 cm. Horizontal (frontal) section at junction of oesophagus, diverticula and mid-gut seen from above. OES, oesophagus; L.DIV and R.DIV, left and right diverticula; INT, mid-gut; AM, mesenteric artery.
The hepatic artery is a branch of the mesenteric artery. It originates from the mesenteric after the latter in a common strand of tissue with the bile-duct has crossed the oesophagus, and either just before or just when the mesenteric becomes attached to the left diverticulum. In this common strand of tissue are present, then, bileduct mesenteric and hepatic arteries. (Fig. 10). Thus the hepatic artery has to run back (i.e. towards the right) first, and traverse this strand over the oesophagus before reaching the liver. It is a very small artery. Arterial pads are present at its origin from the mesenteric.
Figs. 5, 6, 7, 8 and 9.—Ammocoetes, 1.2 cm. long, cross sections. If Fig. 5 be regarded as Section 1, then Fig. 6 = Sect. 13, Fig. 7 = Sect. 17, Fig. 8 = Sect. 113 and Fig. 9 = Sect. 132. Sections cut at 7 microns. The scale on Fig. 5 applies also to Figs. 6, 7, 8 and 9. OES, oesophagus; AM, mesenteric artery; LIV, liver; L.DIV and R.DIV, left and right diverticula; BD, bile-duct; PV, portal vein; SF, spiral fold. Fig. 5: T.S. in region oesophagus and liver and before left diverticulum. Fig. 6: T.S. at anterior end of left diverticulum; note bile-duct and mesenteric artery passing over oesophagus. Fig. 7: T.S., bile-duct opening into left diverticulum, the actual opening is missed in this section. Fig. 8: T.S. just before junction of oesophagus, diverticula and mid-gut. Note position of mesenteric artery in what will become spiral fold. Note dividing nuclei near lumina of diverticula. Fig. 9: T.S. midgut with spiral fold. The caudal face of these sections is shown.
A series of cross-sections (Figs. 5, 6, 7, 8, 9) from an Ammocoetes 1.2 cms. long and a single section from a specimen 8.7 cms. long are given. (Fig. 10).
Fig. 4 is a horizontal section from a 1.2 cm. Ammocoetes.
The spiral fold originates at the junction of oesophagus, diverticula and mid-gut. Its position is then in the mid-ventral line. (Figs. 2, 3, 9).
The oesophagus is lined by a simple epithelium, the individual cells being tall and cylindrical. (Fig. 5). In cross-section the lumen is not circular, but drawn out into four bays. The cells lining the bays are somewhat shorter than the cells between two bays, and these latter cells are ciliated.
If the elements composing the epithelial wall of a diverticulum be isolated, they will be found to consist of two types of cell, which may be spoken of as columnar and glandular. (Fig. 12). Both types extend from the base of the epithelium to the lumen of the diverticulum, i.e. they are of equal length and lie side by side, so that the epithelial wall is only one cell layer deep, though exhibiting two types of cell.
The columnar epithelial cell is tall and extremely thin and attenuated—so much so that it is practically impossible to obtain a correct picture of it from sections, and it was only by isolating the two types of cell that it was possible to realise its shape. For isolation I found specimens which had been fixed in Bouin's fixative and then preserved in 10 per cent. formalin most serviceable. This type of cell is swollen at its free end, i.e. at the end lining the lumen, and these swollen ends fit in between the pointed or gently rounded ends of the glandular cells. The striated border (Stäbchensaum) which lines the lumen appears to be formed entirely at the free surfaces of the columnar cells and the glandular cells not to be concerned in it—the latter seem to end just below the striated border. The basal end of the columnar cell is also sometimes slightly swollen. The nucleus is placed about the middle of the cell—it is narrow and elongate and resembles in shape and structure the nuclei of the columnar epithelial cells lining the remainder of the mid-gut. These
columnar epithelial cells found in the mid-gut diverticula appear to correspond with the columnar epithelial cells lining the remainder of the mid-gut, e.g. in possession of a striated border and in nuclear structure. But they have been slightly modified in the diverticula owing to the great number and relatively greater individual size of the glandular cells present which are packed between them. The modifications referred to are the attenuated shape and the position of the nucleus—in the mid-gut it is basally situated, in the diverticula it is nearer the lumen.
The glandular cells, found only in the mid-gut diverticula, I propose to describe under the following heads: Shape—tall, columnar, slightly wider at the base than at the end near the lumen, with gently pointed to rounded distal (i.e. near lumen) ends which appear to end within or just below the striated border, of the same height as the columnar cells described above. (Fig. 12). Nucleus—large, in section circular to oval, situated in the basal portion of the cell, with
Fig. 10.—Ammocoetes, 8.7 cm. long, cross section. Fig. 10 shows liver, oesophagus, and bile-duct opening into left diverticulum. In same strand of tissue as bile-duct and dorsal to oesophagus are indicated mesenteric and hepatic arteries. Lettering as in Fig. 11.
prominent nucleolus, rarely two nucleoli. The nucleus has a characteristic vesicular appearance, i.e. the nuclear membrane stains, but the content of the nucleus, with the exception of the nucleolus, stains very faintly. (Fig. 11). Thus in section is seen a circular or oval margin (nuclear membrane)—the deeply stained nucleolus frequently appears attached to the inner side of the nuclear membrane—the remaining content appears clear, though high magnifications exhibit a sparse faintly-staining reticulum.
Staining Reactions: After fixation in Bouin, Zenker or Tellyesnickzy with subsequent staining in haematoxylin, the basal or proximal half of the cell stains much more deeply than the distal half. The cytoplasm in this proximal half appears as a coarse darkly staining mass, frequently exhibiting a coarsely fibrillar structure. This is particularly the case after Tellyesnickzy (acetic-bichromate) and iron-haematoxylin. The distal half of the cell after fixation as
Fig. 11 shows opening of bile-duct into left diverticulum more highly magnified. (Same section as Fig. 10). OES, oesophagus; LIV, liver; BD, bile-duct. In this figure (11) the two types of cell (nucleus) in the wall of diverticulum are shown—glandular cells with basal nucleus with prominent nucleolus and columnar epithelial cells with nuclei much nearer lumen. Note flagella in bileduct. Fixation—Bouin.
above and staining with haematoxylin is much clearer and lighter than the distal half—it contains faint but distinct indications of granules—the granules appear as if partially dissolved out. With iron-haematoxylin the granules are rendered more distinct—it is then seen that they are closely packed at the free end of the cell, ready, no doubt, to be cast into the lumen. From this closely packed area
the granules may be traced in diminishing number to about one-third way down the length of the cell. Benda's fixation test for secretion granules (Bolles-Lee, 1921, p. 315) followed by Mallory's triple stain—makes evident the granules in the closely packed area near the
lumen—they are stained red. Strangely enough, the other end of the cell—the region below the nucleus—shows the same staining reaction as the granules—it is also red. The significance of this will appear when the mitochondria are discussed.
Mitochondria: The fixatives of Regaud, Champy and Gatenby followed by iron-haematoxylin were used to demonstrate mitochondria. The method of Gatenby (Flemming-without-acetic and iron-haematoxylin or briefly, F.w.a.) was most useful. By these methods the cytoplasm is stained a homogeneous gray, while granules and mitochondria stain in the same way, i.e. both appear blue-black on the gray background. The mitochondria are abundant at the basal end of the cell, i.e. between the nucleus and the base of the cell, the granules are abundant at the free end of the cell, so that these two opposite regions of the cell are more deeply stained than the intervening region. At the basal end the mitochondria form a tangle—they frequently give the appearance of a cap or a wig of closely interwoven threads seated on the proximal (basal) end of the nucleus. They are very thin structures and appear sometimes as threads, at other times rather as linear aggregations of dots. From this tangle isolated threads emerge, passing up around the nucleus towards the middle region of the cell. These isolated threads may be observed only in very thin sections and may be traced distally to about one-third the length of the cell. Here they come into relation with a structure which I shall refer to as the clear area or vacuole. This at first puzzling structure was first noticed in F.w.a. preparations. Above the nucleus there is frequently to be seen a large and distinct vacuole, as large as the nucleus or larger. (Fig. 13, b, c, d). Within this vacuole any one of the following appearances may be seen (1) a faint reticulum with granules on it, (2) a collection of granules, (3) a number of fairly large globules, deeply stained, (4) two, three or four deeply stained masses, or finally (5) the vacuole may contain a single immense deeply stained mass.
The mitochondria which emerge from the tangle and extend up alongside the nucleus can be seen in favourable cases to reach the vacuole, and at or in the vacuole they appear to give rise to the granules. The large deeply-stained globules or the deeply-stained masses, which are seen at times in the vacuoles, I am inclined to attribute to the fusion of granules—such fusion perhaps being a result of fixation or depending on the particular state of the granules at that time. In all cases fixation was as rapid as possible—the head was cut off, the organs rapidly dissected out and placed in the fixative.
A re-examination of material preserved in Bouin showed that the vacuole was present here also—in any one section a number of cells exhibited the vacuole. The vacuole sometimes appeared empty—usually it contained a mass of stained material, which did not fully fill the vacuole. A more deeply-stained dot was usually noticeable in the middle of the stained mass. (Fig. 13, e). Vacuoles were also abundant in material fixed by Lane's method mentioned below, they were rare in acetic-bichromate material. More careful examination of F.w.a. material now revealed the fact that in cells, which did not
Fig. 13.—Glandular cells of the left mid-gut diverticulum. a, b, c, and d = from Flemming-without-acetic and iron-haematoxylin preparations. Note basal tangle of mitochondria, nucleus with nucleolus, clear area (vacuole) with mitochondria reaching to it and granules. In a the clear area above nucleus was vague and ill-defined. e = from Bouin to show vacuole; f, g, h = from F.w.a. and iron-haematoxylin showing indications of canalicular system; j = from Regaud (formol bichromate) showing canalicular systems with prozymogen granules of three cells—mitochondria and nucleus shown in middle cell; k = from Mann-Kopsch preparations. Golgi network of three cells.
exhibit a vacuole, there was nearly always present in the corresponding region a clear area—this might be just a vague clear area, two or three small circular areas, vague indications of clear canals (canaliculi) or a definite system of canaliculi. Thus in F.w.a. material structures varying from a canalicular system to a vacuole may be seen—all occupying similar positions above the nucleus and about the middle of the cell. (Fig. 13b, c, d, f, g, h). In material prepared by Regaud's formalin-bichromate method, vacuoles are practically absent. I could find only two or three—on the contrary, the intracellular canalicular system is excellently shown (Fig. 13j). It takes the form of a system of clear canaliculi—three examples are shown. An attempt was next made to impregnate the Golgi apparatus—by Cajal's method (Da Fana cobalt nitrate modification) no success was obtained, though several trials were made. By the Mann-Kopsch method, however, an apparatus was blackened about the middle of the cell, occupying a position very similar to that occupied by the canalicular system. Three examples are shown (Fig. 13k). Many observers are of the opinion that Golgi network and canalicular system represent different pictures of the same apparatus, i.e. in formalin-bichromate the material is dissolved out leaving clear canals, in osmic acid impregnations the material is heavily blackened, leaving black cords. If this be so, the most accurate picture of the structure in question is given as Golgi network (Mann-Kopsch) or canalicular system (Regaud's formol-bichromate) and the various structures seen in F.w.a. preparations, varying from canalicular system to vacuole, together with the vacuole itself, represent apparently distortions of the canalicular system. One further point of interest is this—granules are always found associated with this vacuole, clear area or canalicular system, both in F.w.a. and in Formol-bichromate preparations—this is the most proximal region of the cell in which granules are to be seen—from here they may be followed distally to the free end of the cell. That the first-formed granules (prozymogen of Saguchi) are formed under the influence of the canalicular system (Golgi apparatus) there seems no reason to doubt, and from what has been said before, there is reason to believe that the material of which they are formed is derived from the mitochondria.
The thesis I wish to maintain is this—that the glandular cells, which characterise the diverticula, are to be regarded as pancreatic cells comparable to the exocrinous pancreatic cells of vertebrates: in other words, there is in the Ammocoetes stage of Geotria no definite and compact pancreatic gland, but the pancreatic (exocrinous) cells are still scattered in the gut wall in the diverticula. The endocrinous constituent of the pancreas (Islets of Langerhans in vertebrates) is represented by the Follicles of Langerhans in the Ammocoetes.
Schafer (1916) in discussing the pancreas remarks:
1. That the inner two-thirds of the cells are filled with granules;
2. That in haematoxylin-stained sections the outer part of the cell is coloured more deeply than the inner;
3. That pancreas cells frequently exhibit a rounded mass of mitochondria near the nucleus.
Horning (1925) has shown that in the guinea-pig the zymogen granules are constricted off from the ends of the mitochondria. Saguchi (1918) has made an intensive study of the glandular cells of the frog's pancreas. He finds—
1. The nucleus is provided with usually only one nucleolus.
2. After fixatives containing a large amount of acetic acid the basal portion of the pancreatic cell exhibits a fibrillar structure and stains more deeply with haematoxylin. I find the same in the Ammocoetes, particularly after fixation in acetic-bichromate. (Tellycsnickzy). According to Saguchi, this is due to the presence of his “protofibrillae,” which he regards as morphological constituents of the cell. In fixation some of the plasm is removed, the protofibrillae thus individualised and a certain amount of adhesion of them follows, hence the fibrillar structure seen in sections. The protofibrillae are not to be confused with mitochondria.
3. The mitochondria have the form of rods or filaments and are crowded round the nucleus. The mitochondria are used up in the formation of the zymogen granules. Saguchi derives the mitochondria from the nucleus.
4. Zymogen granules are never found between nucleus and basement membrane. Above the nucleus is a clear area—“secretogenous area”—to this the mitochondria converge and here small granules (prozymogen) are formed by the disintegration of the mitochondria. The granules leave this area, increase in size and collect at the free end of the cell as zymogen granules.
5. The Golgi apparatus is placed above the nucleus. It appears to occupy the same position as the “secretogenous area,” where the granules are formed from the mitochondria.
6. After Regaud's fluid (and others) a system of canaliculi with clear lumina may be observed in the “secretogenous area”—within the meshes of this system are prozymogen granules—Saguchi considers the canalicular system is to be identified with the Golgi apparatus, the former being the negative of the latter.
From my own observations I can affirm that the nucleus of the pancreatic cells of trout, frog (Hyla aurea) and rat appears clear and vesicular with a prominent nucleolus. Lane's method for pancreatic islet tissue (Carleton, 1926, p. 279) stains also the zymogen granules of the acinous cells. Pieces of frog pancreas and the Ammocoetes diverticula were prepared by this method. The zymogen granules (frog) and the granules of the glandular cells (Ammocoetes) reacted to the stain in just the same way—both were stained purple.
From the comparisons made above I venture to say that the glandular cells found in the diverticula (Ammocoetes) may be compared to the exocrinous pancreatic cells of the vertebrates. If this be a true comparison, an interesting conclusion follows. We then have in the Ammocoetes the most primitive condition of the pancreas, i.e. the pancreatic cells are still scattered in the gut wall and not compacted into a definite gland. So far as I can find, no pancreatic cells have been described in Amphioxus. Further, such cells (glandular, pancreatic) almost certainly occur in European Ammocoetes, as I shall attempt to show below.
One further point should be noted here—as mentioned before, the epithelium lining the diverticula is provided with a striated border. Within this border may be seen tiny dots or rods (Fig. 11), and in tangential sections it can be seen that these are really sections of a network placed in the striated border. Krause (1923) figures a similar structure in the “Stäbchensaum” of the gut-epithelium of the pike. This structure is the “Schlussleistennetz” or network of terminal bars.
After studying these glandular cells in the mid-gut diverticula of New Zealand Ammocoetes, the question naturally arose—do such cells occur in European Ammocoetes? The mid-gut diverticula are absent in such forms—the anterior portion of the mid-gut suggests itself then as the most probable spot. I have not been able to observe European Ammocoetes myself—but the reports of two earlier investigators—Brachet (1897, 1897a), and Picqué (1913)—have convinced me that such cells occur.
Brachet (1897), at the end of his paper, draws attention to a point in European Ammocoetes which he considers of importance. It is this: “La texture de l'épithélium de l'intestin moyen, est toute différente, dans la partie antérieure, qui fait immédiatement suite au ‘Vorderdarm,’ de ce qu'elle est dans le reste de son étendue.” Here among the ordinary epithelial cells, “on trouve un très grand nombre de cellules toutes spéciales,” which stand out strongly when stained (borax-carmine, safranin) from the others. “Ces cellules, très allongées, s'étendent de la membrane proprà la surface libre de l'épithélium: leur extrémité tournée de ce dernier côté est garnie d'un plateau strié, moins élevé, semble-t-il que celui des cellules ordinaires de l'intestin moyen. Le corps de ces cellules, fortement coloré en rouge, par le carmin ou la safranine, se montre constitué de deux moitiés assez nettement distinctes. La moitié externe est homogène ou très finement granuleuse. C'est elle qui contient le noyau. La moitié interne dirigée vers la surface libre de l'épithélium, se colore moins fortement par le carmin, est moins homogène, montre des granulations plus ou moins nombreuses, et des taches claires irrégulières” … “Ce qui caractérise encore ces cellules, c'est l'aspect tout particulier de leur noyau. Il est constitué d'une mince membrane, très peu chromatique. Au centre du noyau se voit un très gros nucléole, absorbant très fortement les matières colorantes. Il semble que toute la chromatine du noyau s'est condensée dans ce corpuscule.” Brachet remarks first on the zone which these cells occupy “dans la portion initiale de l'intestin moyen,” secondly on their characteristics which suggest those of pancreatic cells. He remarks on Mayr's conception—that in the ancestors of the Selachians, having as yet no pancreas, there must have existed a zone, occupying the dorsal region of the mid-gut, and containing the materials at the expense of which the pancreas forms itself among actual Selachians. “Chez l'Ammocoetes, cette zône paraît exister,
mais elle n'occupe pas seulement la partie dorsale de l'intestin moyen; on la retrouve sur toute sa circonférence. Si c'est là réelement une zône pancréatique, ce que je crois, on peut admettre qu'elle contient les matériaux aux dépens desquels s'édifieront non seulement le pancréas dorsal, mais aussi le pancréas ventral.”
The agreement between these cells described by Brachet and those described by me in Geotria Ammocoetes is striking—position of nucleus, nuclear structure, nucleolus, division of cell body into two halves, presence of granules in inner half. It will further be obvious that the thesis maintained here is not original—it was suggested first by Brachet so far back as 1897, but no one since appears to have followed it up. It was Brachet's paper which suggested to me an explanation of these glandular cells and gave me a means of linking them up with similar cells in European Ammocoetes.
Picqué's paper (1913) is longer, and I do not agree with his main conclusions, but certain points brought out are of interest as regards the glandular cells. He considers a pancreas is present in Ammocoetes and in adult—in his view, with which I disagree—it is formed in the Ammocoetes by the follicles of Langerhans, in the adult by the organ constituted by an aggregation of such follicles, which Cotronei (1927) has since identified as an insular organ. Picqué studied the origin of this organ in very young Ammocoetes (5 mm. to 7 mm. long in P. planeri) and I copy his scheme as Fig. 14. Where the oesophagus is continuous with the mid-gut, two pads, a dorsal and a
Fig. 14.—Scheme showing the disposition of the “bourrelets (pads) d'invagination de l'intestin antérieur (1A) dans l'intestin moyen (IM).” Copied from Picqué (1913). This scheme refers to young larval forms of P. planeri and P. fluviatilis. C.ch. = bile-duct; BID and BIV, dorsal and ventral pads.
ventral, are formed by the oesophagus being slightly invaginated into the mid-gut. The ventral pad is the larger. It is at the level of these pads that the follicles of Langerhans (pancreatic rudiments of Picqué) are formed. Picqué's sections through these pads show externally follicles of Langerhans and internally the intestinal epithelium. The interesting point is this—that in this epithelium two kinds of nuclei are present—nuclei such as occur in the remainder of the intestine and nuclei with large nucleoli, standing out sharply from
the others. On p. 21 we read: “Puis le bourrelet (pad) se dessine (Pl. 1, Fig. 1), constitué par une masse d'éléments cellulaires, dont les noyaux sont surtout caractérisés par un nucléole en général unique et assez volumineux. Ces cellules à gros karyosomes font manifestement partie de l'épithélium intestinal.” Farther down on the same page, “Les coupes suivantes nous conduisent en plein bourrelet. Ici les noyaux innombrables tranchent absolument sur ceux de l'épithélium intestinal par leur nucléole unique, gros et de volume croissant vers le dehors.” Picqué does not explain the presence of these nuclei with large nucleoli. He recognises clearly, however (p. 41), the presence of two types of cells in the epithelium of the pads and thinks the follicle cells (his pancreatic cells) may come from the cells with big nucleoli, but is not sure. He does not discuss these nuclei with big nucleoli any further.
I believe they are the nuclei of the cells which Brachet (1897) had already described in older Ammocoetes. Again Picqué's sections showing the mid-gut epithelium (pads) with two kinds of nuclei show a striking agreement with my sections of the diverticula.
To summarise—in these three cases—the pads of Picqué in Ammocoetes of 5 to 7 mm. length—the epithelium of the most anterior portion of the mid-gut in European Ammocoetes (Brachet 1897)—the mid-gut diverticula of Geotria Ammocoetes—we find a feature common to all—characteristic cells denoted in particular by a nucleus with a large prominent nucleolus. As I have indicated above, these cells are to be compared to the pancreatic (exocrinous) cells of Vertebrates.
It seems possible that Picqué's “pads” and the diverticula of Geotria Ammocoetes are to be regarded as homologous structures, but that in the former case they develop very slightly while in the latter they increase enormously. However, the pads are dorsal and ventral (Fig. 14), while the diverticula are right and left. I have not been able to obtain Ammocoetes smaller than 1.1 cm. long, so as to whether there is any change of position as regards the diverticula in earlier stages I cannot say. That a rotation of the gut may occur is not improbable. A rotation of the gut (Geotria) certainly occurs at metamorphosis, as I have been able to observe.
The position of the follicles of Langerhans is another point of agreement. Picqué finds them in the furrow or groove between oesophagus and the pads of the mid-gut—in Geotria they occupy a similar position, i.e. in the furrow between oesophagus and the origin of the mid-gut diverticula.
Keibel (1927) in his Fig. 8 gives a frontal section passing through the passage of fore-gut into mid-gut of an Ammocoetes, 7.5 mm. long, of Lampetra fluviatilis. The section shows two structures (Wülste) which strongly suggest pads (bourrelets) or the rudiments of mid-gut diverticula. From the section they are right and left, and the left is the larger. Their histological structure cannot be observed. It would be interesting to know if the two types of nuclei (cells) described above are present in them. In his Fig. 10 Keibel shows a sagittal section at the passage of fore-gut into mid-gut of an Ammocoetes 9.2 mm. long, of Lampetra planeri. In the legend he remarks
“Keine Wülste zwischen Vorderdarm und Mitteldarm, aber Epithelgrenze.”
Considering these two sections, therefore, we see that the “Wülste” (structures which I have referred to as suggesting “bourrelets” or rudiments of mid-gut diverticula) are right and left, and absent dorsally and ventrally. They therefore certainly suggest structures, only slightly developed and homologous with the mid-gut diverticula of Geotria larval forms.
Finally it would have to be supposed that in Geotria one pad or diverticulum (the left) had carried forward with it in its development the opening of the bile-duct, since this no longer opens at the junction of oesophagus and mid-gut, but far forward into the left diverticulum.
In this paper the following view is taken regarding the question of the pancreas in lampreys:
Both constituents of the pancreas (exocrinous and endocrinous) occur in the Ammocoetes stage. The exocrinous constituent is represented by the glandular cells occurring in the anterior region of the mid-gut—in Geotria in the mid-gut diverticula. The endocrinous constituent is represented by the follicles of Langerhans.
Only the endocrinous constituent persists in the adult. At metamorphosis the follicles of Langerhans increase in number and become aggregated together to form a definite gland. This is the insular organ which Cotronei (1927) has already described as being composed of insular tissue. In Geotria the diverticula are lost at metamorphosis and with them the glandular cells (exocrinous constituent). Probably these cells are lost also in European Ammocoetes at metamorphosis, but this would have to be ascertained.
The Ammocoetes stage of Geotria australis possesses two forwardly-directed mid-gut diverticula, a left and a right. Into the left opens the bile-duct. Such diverticula are unknown from other Ammocoetes.
The diverticula contain characteristic glandular cells which are to be compared to the exocrinous pancreatic cells of Vertebrates.
In the Ammocoetes stage the pancreas is not yet differentiated as a special gland—we have a stage in which the pancreas cells are found distributed in the epithelium in a certain section of the gut wall. This view was first expressed by Brachet (1897a, p. 773). This paper attempts to confirm this view and to bring fresh evidence in support of it from the study of Geotria.
Addendum: Through the kindness of Dr. Horst Boenig I have received a copy of his recent paper—Studien zur Morphologie und Entwicklungsgeschichte des Pankreas beim Bachneunauge (Lampetra (Petromyzon) planeri). III Teil. Die Histologie und die Histogenese. Zeitsch. für mikr-anatom. Forschung—17 Band, ½ Heft, 1929. Unfortunately I have not got part 1, nor is it obtainable in New Zealand, consequently in the criticism which I offer I feel rather handicapped by not knowing its contents. Dr. Boenig considers that the Follicles of Langerhans, formed as buds from the gut wall and from the epithelium of the bile-duct, constitute in the lamprey a pancreas “Morphologisch dem Pankreas der Höheren Wirbeltiere homolog” (p. 181). Essentially the same view has been expressed before by Picqué (1913) and by Keibel (1927). For the following reasons I cannot subscribe to this view: 1. In Vertebrates the liver and the pancreas originate at practically the same time—here, however, the first indications of the “pancreas”? appear after the liver is completely formed—according to Boenig in 1.2 cm. Ammocoetes—further during the whole larval life “pancreatic” buds continue to be formed, while at metamorphosis the epithelium of the bile-duct proliferates strongly, forming many more “pancreatic” buds (caudal pancreas of Boenig), the bile-duct, as such, disappearing. 2. Though, in the adult lamprey, the cranial and caudal sections of the “pancreas” are respectively dorsal and ventral in position and hence are compared by Keibel and Boenig to the dorsal and ventral pancreas of higher Vertebrates, Boenig (Part 2, p. 591, 1927) himself admits, “dass der Entstehungsmodus des ‘dorsalen und ventralen Pankreas’ bei Lampetra planeri ein ganz anderer ist als der bei den anderen Wirbeltieren” and again “Beim Ammocoetes findet sich weder eine ‘dorsale’ noch zwei ‘ventrale’ Pankreasanlagen.” In fact, the formation of the lamprey “pancreas” will not fit in with any scheme of pancreas-formation, which holds good for other Vertebrates. 3. There is no pancreatic duct—at no time is there ever any indication of one. 4. There is no zymogen tissue nor every any sign of such.
Since the main characteristics of the pancreas, as we know them from other Vertebrates, appear to be missing here, the homology with the Vertebrate pancreas drawn by Picqué, Keibel and Boenig seems to me of very doubtful value. There remains, however, the view originated by Brachet (1897) and advocated in this paper. So far as I know, there is nothing incompatible in the view that these follicles or buds represent islet tissue, either as regards their origin or structure. Cotronei (1927) has already described the “pancreas” of Boenig as an insular organ. The remarkable cells present (a) in the anterior region of the mid-gut in European Ammocoetes (b) in the mid-gut diverticula in Geotria Ammocoetes, bear so many and striking resemblances to pancreatic (exocrinous) cells that it seems reasonable to regard them as such. Neither Picqué, Keibel or Boenig are able to offer any explanation of these cells.
Two further points in Boenig's paper call for notice. Dr. Boenig constantly speaks in Part 3 of the follicles (his pancreas) as being derived “durch Wucherung des Vorderdarmepithels” (p. 179), also on pages 137. 145, 146, 164, etc. This appears strange, since both
Fig. 15.—Microphotograph: T S wall of left diverticulum. F.w.a. and iron-haematoxylin. Note basal tangle mitochondria, nucleus with nucleolus (black), clear areas (circular) and granules in inner half of cell.
Picqué (1913) and Keibel (1927) speak of the follicles as being derived from the mid-gut epithelium, while Boenig himself in Part 2 derives the follicles from the mid-gut epithelium e.g. “Das Pankreas legt sich zunachst; au [ unclear: ] dem Epithel des Mitteldarmes enstehend, multipel in Form einer Spange …” (p. 590). Again on p. 144 Dr. Boenig speaks of Brachet's pancreatic cells as being in the foregut epithelium, but according to Brachet (1897) and Picqué (1913) these cells are located in the mid-gut epithelium. In Ammocoetes of Geotria they are in the mid-gut diverticula.
Brachet, A., 1897. Sur le développement du foie et sur le pancréas de l'Ammocoetes. Anat. Anz., Bd. 13.
—— 1897a. Die Entwickl. u. Histog. der Leber u. des Pankreas Ergeb. d. Anat. u. Entwickl., 5.
Carleton, H. M., 1926. Histological Technique. Oxford University Press.
Cotronei, G., 1927. L'organo insulare di Petromyzon marinus. Pubblicazioni della Stazione Zoologica di Napoli, vol. 8, Fasc. 1.
Dendy, A., 1902. On a pair of ciliated grooves in the Brain of the Ammocoete apparently serving to promote the circulation of the fluid in the Brain-cavity. Proc. Roy. Soc. London, vol. 69.
Giacomini, E., 1900. Sul pancreas dei Petromizonti con particolare riguardo al pancreas di Petromyzon marinus. Verhandl. d. Anat. Gesellschaft auf der vierzehnten Versammlung in Pavia.
Goette, A., 1890. Entwickl. d. Flussneunauges (Petromyzon fluviatilis). Abhandl. zur Entwickl. d. Tiere, Heft. 5.
Horning, E. S., 1925. Histological observations on pancreatic secretion. Aust. Journ. Exp. Biol. & Med. Sci., vol. 2, part 3.
Keibel, F., 1927. Zur Entwickl. d. Vorderdarmes u. d. Pankreas b. Bachneunauge Lampetra (Petromyzon) planeri u. b. Flussneunauge Lampetra (Petromyzon) fluviatilis. Zeitschrift für mikr.-anatom. Forschung. Bd. 8, Heft. 3, 4.
Kner, 1869. “Reise der Österreichischen Fregatte Novarra um die Erde.” ‘Zoologie,’ Bd. 1, Fische, p. 421.
Krause, R., 1923. Mikroskopische Anatomie der Wirbeltiere. Vierte Abteilung. Berlin und Leipzig.
Langerhans, P., 1873. Untersuchungen über Petromyzon Planery. Ber. Verh. Naturf. Ges. Freiburg. i. B., Bd. 6, Heft. 3.
Lee, A. Bolles, 1921. The Microtomist's Vade-Mecum. Eighth edition. London.
Nestler, K., 1890. Beiträge zur Anat. u. Entwickl. von Petromyzon Planeri. Arch. f. Naturgesch, Bd. 56, Heft. 1.
Picque, R., 1913. Recherches sur la Structure et le Développement du Pancréas chez Petromyzon. Mém. de la Soc. Zool. de France, Tome 26.
Plate, L., 1902. Studien über Cyclostomen, 1, Systematische Revision der Petromyzonten der südlichen Halbkugel. Faun. Chil. Zool. Jahrb. Suppl. 5, 4 Heft., 2 Bd.
Saguchi, S., 1918. Studies on the glandular cells of the frog's pancreas. Amer. Journ. Anat., vol. 26.
Schafer, E. A., 1916. Essentials of Histology. Tenth edition. London.
Schneider, A., 1879. Beitrage zur verg. Anat. u. Entwickl. d. Wirbeltiere. Berlin.
Smitt, F. A., 1901. Poissons d'eau douce de la Patagonie. Bih. K. Svensk. Vetensk.-Akad. Handl., Bd. 26.
Raised Beaches and other features of the South-east Coast of the North Island of New Zealand.
[Read before the Wellington Philosophical Society, 13th August, 1930; received by Editor, 17th August, 1930; issued separately, 25th November, 1930].
Cape Terawhiti to Port Nicholson.
Port Nicholson to Orongorongo.
Orongorongo to Lake Onoke.
Lake Onoke to Cape Palliser.
Cape Palliser to Pahaoa River.
Pahaoa River to Flat Point.
Flat Point to Whareama River.
Whareama River to Okau.
Correlation of Platforms.
The district described in this paper comprises the coastline of the southern and south-eastern portion of the North Island of New Zealand. A narrow strip of country inland from the coast itself was also examined, so that the bearing of the rocks of each locality on the type of coastline could be considered. Thus the description of each strip of coast is prefaced by a note on the geological structure, or the rocks of the locality, as it has been found that the type of present-day coastline is profoundly affected by the geological formation of the country.
Literature on the coastal features is fairly complete for the Wellington area, Crawford, Park, Bell, Cotton, Adkin, and Aston having each contributed one or more papers; but the Wairarapa coast has received little attention. Crawford and A. McKay recorded raised terraces but neither described them, though McKay estimated the height of the Palliser Bay platforms. Hence this portion of the work provided a virgin field.
The thanks of the writer are here gratefully extended to all those who have so kindly afforded him accommodation on a much exposed and thinly populated coast, without which help the work would have been extremely arduous. To Mr. Jobberns, of Christchurch, his sincere gratitude for a trip along the Canterbury raised terraces is here expressed. The writer is also indebted to Dr. Cotton for permission to reproduce one of his sketches. (Fig. 4).
Cape Terawhiti to Port Nicholson. (18 miles).
Geographically, Cape Terawhiti provides a very convenient starting point for this paper, for it is the most westerly point of the south coast of the North Island and so forms the western limit of one of the coasts with which this paper is concerned. Furthermore, it is shown on the majority of maps and so is widely known, in name at least. From Terawhiti east, as far almost as Lake Onoke at the head of Palliser Bay, the rocks consist of a single series of hard, contorted greywackes and argillites across the strike of which, the shoreline cuts, for the main part, at right angles. The coast is bold and rugged, the country rising rapidly to over 1000 ft. Usually, cliffs several hundred feet high front the sea, which, until recent times, has been strongly attacking them. Owing to a comparatively recent movement of the strand the sea no longer reaches quite to the foot of the cliffs. The present shoreline consists of stretches of sand or gravel beach, alternating with wave-cut platforms which project seaward from many of the more prominent headlands.
So far as any discussion on the raised beaches of the district is concerned, Terawhiti is again most suitable, for, just south of the Cape itself is a splendid example of a marine cut platform which has been raised to a height of 125 ft. above sea-level. The surface is smooth; only a few stacks 6 ft. high, now rapidly disappearing under the action of the normal subaerial agencies, still stand above the otherwise level surface. The rear edge of the platform is covered in part by talus, accumulating at a rapid rate from the steep slopes, which rise sharply to a height of 1500 ft. This makes somewhat difficult any accurate determination of the amount of uplift that has taken place, but the mean of a number of estimates gives a value of 125 ft. A covering of six or eight feet of discoidal gravel, up to ¾ in. in diameter, may be seen where the protecting grass has been removed. This thinness of the grael cover is characteristic of all the platforms from Terawhiti to Tongue Point. The explanation may be that, just as the strong swell and current causing the Terawhiti tide rip pass through Cook Strait to-day, so, during the period in which the benches were cut, there was a strong tidal or ocean current which swept most of the debris, derived from the land and resting on the cut shelf, off into deep water, thus keeping the rock surface compartively clean.
A remnant of a higher platform, now 250 ft. above sea level also occurs at Cape Terawhiti. The surface of this platform is almost completely obscured by talus but there can be no doubt of its existence, especially when seen in profile from the other side of Oterongu Bay. (Plate 75, Fig. 1). This prominent higher bench is of the utmost importance as it occurs in every locality along the south coast where the lower or younger platform is well developed; but, just as the lower is present at different heights in different localities, so there is no constant height, or ratio of heights, between the upper and lower platforms. This seems to prove that warping and tilting occurred either during or between the periods of uplift, just as differential warping of a comparatively late age has been
shown by Cotton (1921B, p. 131 et seq.) to have governed the form of the Port Nicholson depression.
Along almost the whole of the coast from Terawhiti to Tongue Point the lower platformis continuous. A few small streams have cut gorges 20 yards wide across it at intervals, but there can be no doubt as to its continuity, even though it is not uniform in height. Observed from the sea, it forms one of the most prominent coastal features, though at no place is it more than 100 yards wide and usually only a few feet across. From a height of 125 ft. at Terrawhiti it descends to 110 ft. at the head of Oterongu Bay, though this lesser height may be due to slumping of the rocks which are here traversed by an intense shatterbelt. Thence it rises somewhat abruptly to 145 ft. at the east end of Oterongu Bay. For the next mile it continues horizontally, after which it rises gradually in the course of two
miles or so to 270 ft. a little to the west of Tongue Point. It was this change in height that induced Park (1910, p. 586) to say that he had satisfied himself that it was not a marine platform of erosion; but his alternative hypothesis of a glacial origin can hardly be deemed so convincing as the theory that he attempted to overthrow. Throughout its length the platform exhibits the same thin veneer of beach gravels that was noted at Cape Terawhiti. A glance at Plate 75, Figs. 1 and 2 will serve to suggest a relationship between the benches in the two localities and the following of the lower platform continuously from one to the other shows that they are to be correlated in spite of the disparity in height, those at Tongue Point being twice as high as those at Terawhiti.
The Tongue Point platform, undoubtedly the finest west of Port Nicholson, has been described by Cotton (1912, p. 255). Along its base it is over a mile long and it reaches a maximum width of almost half a mile, the height at the rear being 240 ft. As noted by Cotton, even the coarser beds of beach cover attain a maximum thickness of
only eight feet. This also bears witness to the strength of a former Cook Strait current. Unlike the other rock platforms, Tongue Point is quite free from any stacks or unconsumed upstanding rock masses. It presents, therefore, a remarkably even surface with an average seaward slope of 5°, which is as yet almost untraversed by streamlets. This may be attributed to the fact that the platform is flanked by two large streams, the Waiariki and the Karori, which effectively drain the country behind the platform so that the only run off is from the surface of the platform itself and the steep cliff at the rear.
At Tongue Point, as at Cape Terawhiti, a second (higher) bench is present at twice the height of the main platform, i.e., at 480 ft. (Plate 75, Fig. 2). It is developed to the same relative extent as that at Terawhiti and although no intervening bench remnant could be found the two must undoubtedly be correlated.
Fig. 3.—To show the height relation of the shoreline of the Tongue Point Cycle (dotted line) to that of the present day.
T. Terawhiti. R.S. Runaround Stream. B.H. Baring Head.
T.P. Tongue Point. P.N. Port Nicholson. O. Orongorongo.
Between Tongue Point and Port Nicholson no other raised marine platforms were observed but most valuable data may be obtained by a consideration of the amount of rejuvenation shown in many of the stream courses. By measuring the heights of the old valley-forms a regular sequence of uplifts was obtained in support of Cotton's “Port Nicholson Warp” theory. Fig. 3, drawn from the above data and showing the relation of the ancient shoreline of the Tongue Point Cycle to that of the present day, demonstrates clearly the nature of the warp as distinct from any faulting. Between Island Bay and Haughton Bay no movement is apparent and then succeeds the drowned region of Lyall Bay and Port Nicholson. The question remains:—Was the Tongue Point shoreline uplifted uniformly (or subuniformly) and subsequently locally downwarped to form Port Nicholson, or was the Port Nicholson district downwarped at the same time as the Tongue Point-Terawhiti coast was arched up? From the fresh appearance of the Wellington Fault Scarp which bounds the depression to the north-west it seems that the drowning movement was separate from and succeeded a more general movement of uplift which concluded the Tongue Point Cycle of erosion. Cotton (1921B, pp. 134-135) inferred, from the fact that the raised marine platforms to the east are parallel or subparallel, that the depression was quite recent. As the present writer is strongly of the opinion that the platforms to the east of Port Nicholson must be correlated with those to the west, and have been produced by the sea during pauses in the same series of movements, discussion of the sequence of orogenic movments is deferred until the Orongorongo platforms have been described.
Port Nicholson to Orongorongo. (6 miles).
About a mile east of Port Nicholson, appear the mouths of two small drowned valleys, both now almost closed by shingle bars. Except for these, the beach is continuous from Port Nicholson to the mouth of the Waiuni-o-mata River, and thence to the Orongorongo. In Fitzroy Bay a raised beach of shingle is present some forty yards from the sea at a height of 20 to 25 ft. Cotton (1921, p. 139) regards this as the pre-1855 storm beach ridge, though it is flat across the top and in places over 25 yards wide. It is thus far too high, wide, regular, and well preserved for a storm beach such as the pre-1855 beach would be. Between the Wainui and Orongorongo rivers, several ancient beach ridges (now confining lagoons on the strand plain) may be recognised but they are not at so uniform a height as their equivalents to the east of the Orongorongo. Along the west bank of the Orongorongo an exposure shows that the 30 ft. level is cut in rock to a considerable width.
Fig. 4.—Diagram-sketch of the southern end of the tilted area east of Port Nicholson. From left (north-west) to right (south-east) the coastal features shown are: Pencarrow Head, Lake Koangapiripiri, Lake Koangatera, Fitzroy Bay, Baring Head, Wainui-o-mata River, Orongorongo River, Cape Turakirae. (From Cotton).
Throughout its length the beach is backed by high cliffs which exhibit an even crestline formed by the edge of a raised marine terrace. A series of such terraces is present (Cotton, 1921B, p. 135) all tilted to the west, i.e., towards the downwarped Port Nicholson area. These terraces were fully investigated and carefully described by Cotton (op. cit.), so little need be repeated here.
A summary of the benches present is, however, given for the sake of continuity and for comparison with other benches recorded in this paper. As all the platforms are tilted to the west, correlation is a matter of detailed field work, and a statement of heights alone is deceptive and misleading. The following are Cotton's determinations and correlations:—
|Gollan's Valley to Wainui.||Baring Head.||Wainui to Orongorongo.|
|Wainui Platform.||—||Orongorongo Platfrm.|
|—||Baring Head No. 3.||—|
|—||Baring Head No. 2.||—|
|—||Main Baring Head Platform.||Continuation of Main Baring Head Platform.|
The Baring Head Platform, between the Wainui and Orongorongo rivers, where the covering of waste ranges up to 50 ft. in thickness, is at heights, from west to east, of:—385 ft., 500 ft. and 480 ft., while the Orongorongo Platform above it is at heights of:—760 ft., 890 ft., and 870 ft. These observations were made with an aneroid barometer along the rear edge so that the terraces appear parallel within the limits of observation. Both show a marked drop of 20 ft. at the eastern end.
Comparison of the benches to the east of Port Nicholson with those to the west shows that there are no grounds upon which indisputable correlations can be made, but the following are suggested as probably correct.
|Upper Bench, 240 ft.||Upper Bench, 480 ft.||Orongorongo Platform, 890 ft.|
|Lower Bench, 125 ft.||Lower Bench, 240 ft.||Baring Head Platform, 500 ft.|
On this basis the analysis of the earth movements is as follows:—
1. A strand line as represented by the highest bench at Orongorongo is the earliest stage recorded.
2. The second highest bench at the Orongorongo indicates an uplift of the order of 125 ft.
3. The cycle of erosion exemplified in the upper platforms at Terawhiti and Tongue Point, the “Wainui” platform and the “Orongorongo” platform was a well marked one of some duration, separated from 2 above by an uplift of some 50 ft. at Orongorongo.
4 and 5. Two short periods of stillstand are represented by the two small benches at Baring Head. They show that uplifts of 240 ft. and 80 ft. have taken place.
6. The main platforms at Terawhiti and Tongue Point, and the Baring Head platform represent Cotton's Tongue Point Cycle of erosion, which apparently was ushered in by an uplift of not more than 80 ft. near Orongorongo.
7. Uplift, probably as a series of movements, brought the coast to a position a little higher than its present level.
8. The Port Nicholson downwarp.
9. Subsequent slight uplift of a few feet to present level.
All the above estimates of uplifts are for the Orongorongo area, where the maximum movement seems to have taken place. Most of the movements in the past seem to have been tilting to the west, thus suggesting the presence of a hinge-line out in Cook Strait about twelve miles west of Cape Terawhiti.
Orongorongo to Lake Onoke. (14 miles).
To the east of the Orongorongo River the fringing plain is broader, until at Cape Turakirae it is over 400 yards wide. Along the west side of Palliser Bay, however, its width diminishes gradually until it is only a few yards across. Throughout much of its length well marked ridges of beach gravel are present, four being visible at the mouth of the Orongorongo at heights of: 12, 22, 32, and 44 ft. above high water mark, although the 12 ft. beach ridge was probably formed by the sea while at its present level. At Cape Turakirae, Aston (1912, p. 209) estimated the heights as 9 ft., 40 ft., 60 ft., 80 ft., and 95 ft., but these values appear to be too large, the height of the last being only 70 ft. In addition to the well-marked ridges of beach gravel the plain is strewn with great boulders (“monoliths” of Aston) in the neighbourhood of the Cape, giving an exceedingly rugged appearance to the surface. Along the greater part of the western Palliser Bay coast a 25 ft. raised gravel beach is prominent, in places backed by remnants of a 50 ft. raised cut rock bench covered with coarse detrital deposits (Plate 76, Fig. 1). In the face of the old sea cliff fronting this platform are several ancient marine caves, some of which have been figured by Cotton (Geomorphology of N.Z., p. 423). This bench is of marine origin but farther north, at the mouth of the Muka Muka Stream, the wide 50 ft. terrace may be partly stream cut. The fine gravels covering it show no distinctive characters.
The uplifted platforms of the Baring Head series have been traced only as far as the west bank of the Orongorongo River. On the east side of the river practically no traces of them can be found. The sudden disappearance of such prominent features of the landscape has proved one of the most baffling problems of the district, especially when it is remembered that the later periods of uplift, represented by the shingle ridges and the coastal plain, are better developed to the east than to the west. No satisfactory explanation of the facts has been presented as yet, nor can one be offered here.
In addition to the 25 ft. gravel beach and the 50 ft. rock bench on the western side of Palliser Bay, the profile of the hills facing the sea is suggestive of a high level terrace with a considerable slope towards the Wairarapa Valley. This series of possibly marine remnants is present in two localities south of the Muka Muka Iti Stream at a height of 510 ft. at 335 ft. on the north side of the Muka Muka Iti, and at 225 ft. at the Muka Muka where there are unconsolidated
covering beds 30 ft. thick. All these high level terraces are of somewhat doubtful origin but the most probable explanation is that they are marine.
At Eglinton's, in the north-west corner of the Bay, a considerable area is even surfaced but it has too great a slope seaward to appear to be a marine bench. It was probably cut by the Ruamahanga River. On account of the slope the writer could give no estimate of its height. A small flat area facing Lake Onoke may, however, be a continuation of the platform which is so prominent to the east of the Laké.
Lake Onoke to Cape Palliser. (23 miles).
Lake Onoke is protected from the sea by a broad gravel beach or bay bar some two miles long, sometimes continuous from side to side and on other occasions broken by a gap through which the surplus waters of the lake escape. The presence of such an outlet is governed largely by the state of the sea, which throws up gravel to block the passage in times of storm, the outflow from the lake being sufficient to clear a channel in good weather.
To the east, along the head of Palliser Bay, the cliffs, cut in soft Tertiary mudstones (Pliocene to the west and Miocene at the eastern corner), rise in places to 200 ft., but are now usually protected from marine undercutting by a beach of coarse sand which extends without a break from the lake outlet to the north-east corner of the Bay. The material for this beach would appear to be derived from the greywacke rocks which outcrop along both sides of the Bay, though, according to Marshall (1929, p. 345), sand is not usually produced by the wearing of gravel on a beach. From the north-east corner of the Bay to the Waitarangi Stream most of the shore is unprotected by beach deposits and so active cutting back of the soft Tertiaries is now in progress, and the cliffs are retreating at a rapid rate. This recession is measurable at the Waitarangi Woolshed, which was built many years ago at some distance from the sea. Now it is in danger of being engulfed; indeed some of the mustering yards are already fast disappearing, the encroachment having been of the order of 25 ft. in the last six years. This portion of the coast receives the force of the south-westerly gales far more than does the head of the Bay and is also nearer the source of the hard greywacke detritus which supplies the abrasive material, so that erosive action is at a maximum in this locality.
Southward of the Waitarangi Stream a broad, uplifted coastal plain makes its appearance and extends almost continuously along the coast for the next 45 miles to the mouth of the Pahaoa River. In only two places throughout this distance was any evidence found of a rock cut base to the platform, the surface in general being thickly covered with gravel, both marine and alluvial. Shingle fans have been formed by most of the streams debouching from the high country to the east, which rises rapidly to a height of 1000 ft. or more, and these fans cover most of the surface of the coastal plain. (Plate 77, Fig. 1). At Black Rocks Point this platform attains a maximum
width of 400 yards and shows four successive subparallel beach ridges all at about the same height. An uplift of 30 to 35 ft. was apparently responsible for the laying bare of this fringing plain.
Midway between Black Rocks and Cape Palliser, hard Tertiary rocks, apparently not hitherto described, though figured by Hochstetter (Geologie von Neu Seeland, Novara Exped., p. 3), outcrop over a small area, striking N. 20° W. and dipping S.W. 60°. They consist of a basal conglomerate 1 ft. thick of well-rounded pebbles; sandstone 50 to 60 ft.; and an arenaceous limestone, 30 to 40 ft., containing fragments of cirripedes, brachipods, polyzoa, echinoids and corals; but the fossils are too poorly preserved and the matrix is too hard to allow collecting.
At the head of Palliser Bay is an extensive terrace which, broken only by the Whangaimona River and its tributaries, stretches from Lake Ferry to the east side of the Bay, where it is continuous with the platform which is so prominent along that portion of the coast. The terrace is not level but rises from 100 ft. at the east side of Lake Onoke to over 300 ft. at the eastern end. At the rear is an even-crested ridge also ascending eastward until it is comparable with the second platform along the eastern side of the Bay, i.e., at 575 ft. Throughout its length this ridge is unbroken, straight and evencrested. The presence of this ridge precludes any possibility of a river origin for the terrace at the head of the Bay unless it be the work of the Whangaimona River which seems now too small to cut such an extensive terrace, a mile and a half wide and five miles long. Further, a river origin leaves unexplained the straightness of the rear edge. No gravel deposits such as might give a clue to the origin were observed. As both the terrace and the even crestline of the ridge at the rear appear to be the continuations of undoubtedly marine platforms along the east side of the Bay, they may for the present, be considered to have been cut by the sea.
Along the whole of the east side of the Bay a well-preserved series of raised platforms affords probably the most striking feature of the coast. When they are seen from a distance the interrelation of the platforms is not very clear for two reasons: (a) There is a general tilt downwards from the opening of the Bay to its head and (b) The benches have a varying development relative to one another at various points along the distance through which they are found. The main platform rises at a gradient of 25 ft. per mile southward, and the higher ones are also tilted to about the same extent. Although the character of the rocks varies from soft Tertiary mudstones at the north end to the hard Trias-Jura greywacke of the Haurangi Mts. at the south end of the Bay, there is little difference in the stage of development reached by the platform in each case.
The terraces are best developed at the following localities:—
(a). Head of Palliser Bay as already described. The heights at the east end are: Terrace, 300 ft.; Ridge crest, 575 ft.
(b). Just north of Hurupi Creek: 425 ft. and 730 ft.
(c). Behind Waitarangi Station: 460 ft., 545 ft., and 800 ft. The 460 ft. terrace is 200 yards wide, the 545 ft. terrace is clear, but only a few yards wide, both being well cliffed and the third, or 800 ft. bench is also well defined. (Plate 76, Fig. 2).
(d). Te Hamenga Point: The top of the point itself is formed by the second lowest terrace (the lowest being cut away south of Waitarangi) and has a strong tilt along its length, rising from 520 ft. at the stream on the north side to 660 ft. at the Otakoha Stream on the south. At the north end this platform shows very plainly 30 ft. of well-worn, even-graded beach gravel. Other terrace remnants are present at heights of 855 ft. and 965 ft., but well-defined cliffs do not show at the rear. The absence of strong cliffing is due to subaerial weathering, which has rounded the formerly steep slopes, though the line of the ancient cliffs is still distinctly traceable.
(e). Black Rocks Series: The heights of the main platform are: 1. One mile north of Tilson's Whare, 675 ft., with a covering of 20 ft. of marine gravel. 2. Opposite Tilson's Whare, 710 ft. 3. At Black Rocks, where there is a covering of 30 ft. of subangular to rounded gravel, 700 ft. There are also forms suggestive of a higher terrace at approximately 950 ft.
As remnants of the same terrace occur at different heights due to tilting of the platforms, some scheme of correlation becomes necessary. The following table is therefore given:
|Black Rocks.||Te Hamenga.||Waitarangi.||Hurupi Creek.||Bay Head.|
|950 ft.||855 ft.||800 ft.||730 ft.||575 ft.|
|700 ft.||600 ft.||545 ft.||—||—|
|—||—||460 ft.||425 ft.||300 ft.|
Towards the south end the terraces are dissected by numerous streams which have cut gorges some hundreds of feet deep through them. The traversing of such an area becomes extremely arduous as it is necessary to descend to sea level each time in passing from one terrace remnant to another. These mountain streams have transported the waste which now covers the surface of the coastal plain, and, considering that some of them descend almost 3000 ft. in four miles, it will be seen that they are capable of carrying an unusually large quantity of detritus. Some idea of the nature of the country may be obtained from Plate 77, Fig. 2.
Cape Palliser to Pahaoa River. (30 miles).
From Cape Palliser to the Pahaoa River the rocks outcropping on the coast are, almost without exception, the greywacke of the Haurangi Mountain Range, similar to that of the Wellington area. At only a few localities are the younger rocks present, where they are usually represented by flaggy limestones. The observed outcrops of the younger series are:—(1). Opposite White Rock Station. (2). At the mouth of the Opuawe River. (3). At the mouth of the Awhea River, and (4). At the mouth of the Hangaroa River. The age of this limestone is in doubt, though McKay (1879, p. 79) regarded it as the equivalent of the Amuri Limestone. It is certainly Notocene
in age as distinct from the Trias-Jura greywacke. To the south of White Rock Station the effect of the disparity between the two rock types is admirably shown in the topography, the greywacke standing up, bounded by precipices 1500 ft. high, above the rounded, subdued forms produced by subaerial weathering on the younger beds. (Plate 78, Fig. 2).
For almost the whole distance under review the coastline consists of the towering greywacke cliffs fringed by a narrow strip of uplifted rock-and-gravel platform such as has already been described. (Plate 78, Fig. 1). Indeed, for the greater part of its length, this coast is wild and rugged in the extreme. To the north, at the Devil's Mile, the rock, as is not unusal in the greywacke series, is crushed and shattered into “rotten rock,” an almost unconsolidated fault breccia, so that the sea now reaches to the base of the cliffs except at low water. At the north end of the “Mile” much “rotten rock” comes down to form a talus slope and fan, the seaward edge of which is now strongly cliffed.
A mile or so to the north of Cape Palliser the coast is strewn with gigantic boulders or “monoliths” similar to those at Cape Turakirae, where the character of the country is in every respect akin to that of the locality just studied.
Pahaoa River to Flat Point. (18 miles).
The rocks between Pahaoa and Flat Point are more varied than those farther south. At the mouth of the Pahaoa (north bank), there is a ridge of limestone and between Pahaoa and Flat Point, outcrops of this and a similar limestone are not infrequent. Notably they are present: (1) on the north bank of the Pahaoa; (2) at the mouth of the Waihingaia Stream, where it is strongly shattered and the fissures are filled with calcite; (3) a few hundred yards north of the Holey Rock Lighthouse, where also it is somewhat crushed; (4) in the hills west of Glenburn Station, where stalagmites have been formed below overhanging cliffs; and (5) near the tip of Flat Point itself, where it stands above the beach deposits as a rugged outcrop. Crawford (1868, p. 17, essay) has also noted:—“At Waikekino, six miles south of Flat Point, reefs of Amphibolite are found on the shore or in the sea, penetrating the above named calcareous rocks, and boulders of various trappean rocks are common in the Kaiwhata and other rivers.” In his 1869 report (p. 351) he also referred to “Diallage traversing limestone” at Waikekino. This outcrop was not observed by the writer but pebbles of igneous and dyke rocks are very common along the shore in this locality, though no specimens were seen in situ. The specimens found were probably transported down the rivers from outcrops known to exist farther inland, thus accounting for the non-observation of any coastal outcrops, while Crawford's original outcrop being “in the sea” in 1868 may have been since demolished. A highly glauconitic sandstone usually underlies the limestone and was noted at nearly all the outcrops of this rock.
At the mouth of the Pahaoa a 35 ft. terrace is strongly in evidence. From its position it might be regarded as of fluvial origin
but for the fact that well-marked beach ridges of sand, now firmly bound by vegetation, occur regularly across it parallel with the present shoreline. These ridges prove that, though the river may have cut the platform the material now covering it was arranged by the sea prior to and during the uplift of 35 ft. On his visit to the locality the writer could obtain no evidence as to which agency originally cut the bench. At places along this uplifted strand small streams, debouching from ravines in the higher country at the rear, have built shingle fans across the inner edge of the platform. These are quite distinct from the old beach deposits and there can be no doubt that river action had little to do with the present appearance of the strand plain apart from the supplying of waste.
North of the Pahaoa the plain gradually becomes narrower until the sea reaches the base of low cliffs, some of which are cut in shingle fans. A short stretch of sandy beach covered with large dunes succeeds northwards, presumably as a temporary phase in the general cutting back of the shoreline, and then the 30 ft. platform again makes its appearance, either as bare rock or covered with coarse shingle. Beyond the Holey Rock Light it gardually becomes covered with finer material and about two miles south of Glenburn Station is grassed. All along from the Pahaoa to the Waikekino Stream there thus appear indications that the coast has undergone an uplift of 35 ft., that is, a definite movement of the strand has taken place. The coast north of this point, i.e., the Waikekino Stream, though presenting a strand plain, the inner edge of which is about 35 ft. above sea level, shows no definite evidence of uplift, as sand will easily form dunes 35 ft. above high-water mark. Rock outcrops are not found on its surface, and, as distinct from a plain composed of solid rock with only a comparatively thin covering of soil, the whole coast has the appearance of a strand prograded merely by the accumulation of waste governed by marine agencies. (Plate 79, Fig. 1). It presents a fine beach, inland from which much of the surface is covered either by traces of successive beach ridges or great wandering sand dunes, which, over much of the surface, especially at the north end, have obliterated all trace of the regular ridges, and, finally, the swales between many of the later-formed beach ridges are sometimes marshy. The coast immediately to the south, however, shows no good beach and is a rock bench, either bare or only thinly covered with coarse gravel; a surface from which moisture drains away almost immediately.
The peculiarity of this short stretch of nine miles or so lies in the fact that it has prograded a distance of 500 yards although the coast to the south is subjected to extremely active marine erosion which must have been wearing and cutting the coast for a very long period, producing towering cliffs behind the fringing plain; and to the north the sea now reaches (beyond the Kaiwhata) to the foot of 150 ft. cliffs which are being rapidly worn back. Flat Point itself forms the northern end of the prograded section of the coast but is not sufficiently prominent to deflect coastwise currents and form a backwater in which waste derived from the rest of the coast might accumulate, indeed the point itself is mainly of a prograded nature.
A prominent terrace is continuous at about 500 ft. almost all the way from Glenburn to Flat Point. (Plate 79, Fig. 2). The most southerly remnants may be observed near the Holey Rock Light where they are at a height of 450 ft. and are capped with well-sorted, stratified marine gravel. Towards Glenburn the remnants become more prominent and continuous, and the rear edge rises gradually to 470 ft. North of Glenburn Station there can be no doubt of the continuity of the platform, though small streams cross it in deep ravines. Stratified gravel deposits cap it a mile to the south of Flat Point, where the height is 490 ft. At Flat Point it is approximately 500 ft. and three-quarters of a mile wide but is dissected almost parallel to the coast by two large stream valleys, while at its seaward edge it is cut off by the steep cliffs at the rear of the prograded Glenburn-Flat Point beach. Northward is descends somewhat and grades into the 450 ft. levels at the Kaiwhata.
The origin of the stream-valleys now almost parallel to the coast and dissecting the platform along its length is of interest, as to-day the terrace still slopes seaward. It seems that they must be subsequent as they are parallel to the strike of the country and opposed to the slope of the plain. They flow into a stream which crosses the plain in an almost straight line from the hills to the sea.
Flat Point to the Whareama River. (16 miles).
The rocks along the coast from Flat Point to the Whareama River are, almost without exception, soft sandstones and mudstones of Middle Tertiary age, usually in alternating bands about 6 inches thick. These present but little resistance to marine and subaerial agencies, both of which are actively engaged in wearing back the coastline at a rapid rate. So non-resistant are the rocks generally, that it is rare to find a well-developed platform at the base of the cliffs, or a distinct nip where storm waves are most active.
North of Flat Point the prograded coastline abruptly changes to one where rapid cutting back is in progress, and for four miles towards the mouth of the Kaiwhata River a steep beach of boulders is encountered. Just south of the Kaiwhata the cliffs are being attacked and this phase is then continuous as far as Uriti Point, seven miles to the north. Pebbles of igneous rock occurring among the dune deposits at the point are well rounded, indicating that they have travelled a long distance, and as no outcrop of any such rock was found on or near the coast in this locality, this conclusion is strengthened. From Uriti Point onward to the Whareama a well-developed sandy beach is in evidence, at the south end it is fine and hard, at the north coarse and very soft.
At or near the mouth of the Kaiwhata River an extensive series of raised terraces is developed, some of river and some of marine origin.
(1) At 8 ft.—This terrace is merely produced by lateral erosion on the part of the river and there is no evidence that it represents a period of standstill of the standline. It is poorly developed.
(2) At 30 ft.—This terrace is well exhibited for 600 yards up the stream and its presence on both banks shows that it was originally
of river origin and cut during a period of standstill; for it must be impossible for the sea to cut a terrace only 120 yards wide at the mouth and penetrating 600 yards inland, cut, moreover, not along a weak band in the country rock, but at right angles to the strike of the beds. This terrace is now covered by 4 ft. of marine gravel, above which is 5 ft. of fine deposit crowded with Recent marine molluscan shells, mostly in a good state of preservation, showing that the bench must have been submerged after it was cut by the river.
Further evidence of this submergence is afforded by a mudstone of recent origin, almost certainly contemporaneous with the marine conglomerate and covering beds of the Kaiwhata 30 ft. bench, and crowded with marine mollusea of recent species which outcrops for a short distance up the next four creeks to the north of the Kaiwhata. The outcrops become smaller and smaller towards the north. The most striking evidence of submergence, however, was disclosed on the occasion of the writer's second visit to the district. Great changes had occurred about the mouth of the river. On the first visit it was easy to cross dry shod by means of a high storm beach of gravel thrown up by the sea which damned the river to produce a lake 75 yards wide and 600 yards long; the outflow from which seeped through the gravel to the sea. On the second visit the river mouth was open to the sea. Owing to much rain in the back country the river had broken the dam and built a temporary bar (about awash at high water) 30 yards seaward of the previous high tide mark. Inside the area thus enclosed the river had exercised a scouring action and disclosed the trunks of 22 trees, all upright in the position of growth, previously covered by the sea and marine gravel, just seaward of the beach. That these trees were actually in the position of growth is shown by the fact that many were slender tree ferns without spreading roots, so that if overturned, they would not subsequently regain the vertical position. Another tree stump, which, though not protected by the bar, had been uncovered by the outwash, and overturned by the force of the waves, was also found to the north.
Still other trees with their roots in ancient soil on the Middle Tertiary mudstones projected up through the Kaiwhata conglomerate into the covering shelly beds. (Plate 80, Fig. 1). These are apparently of an age quite distinct from that of the stumps described above, and the oscillations of the strand in this locality, as represented by the two sets of trees, the 30 ft. bench and beds, and the modern shore appear to be:—
(a) The Middle Tertiary rocks were planed by the river and the upper set of trees grew on the area so planed.
(b) Subsidence of ten feet or so during which the Kaiwhata conglomerate and overlying beds with marine shells were deposited.
(c) Uplift of 25 ft. when a marine bench was cut in the soft Tertiary rocks.
(d) Further uplift when trees grew on the bench so cut.
(e) Depression of 2 or 3 ft. more than the previous uplift so that the trees then growing are now below sea level.
Half a mile farther north, at the mouth of a small unnamed creek three more tree trunks (tree ferns), the roots of which are now
below sea level, were exposed by a fresh coming down the creek. It seems impossible that these tree ferns could be in other than their position of growth, for otherwise they would not be standing upright.
(3) and (4) At 42 ft. and 100 ft.—Both of these terraces are confined to the south side of the valley and were almost certainly produced by lateral erosion on the part of the stream.
(5) On the south side a terrace is present at 240 ft. and on the north side at 180 ft. The slope on each of these terraces suggests that they are one and the same, and that northward the 180 ft. level grades into and forms the 150 ft. level of the Homewood area. Thus near the Kaiwhata the platform appears to be tilted with a slope down towards the north.
(6) At 450 ft.—Here a flight of terraces, now strongly dissected, is present tilted in the same manner as the lower bench, so that, on the evidence available, it seems that this terrace is the continuation of the 500 ft. Flat Point terrace, and that it slopes down northward to form the 350 ft. Homewood level.*
In the Homewood District flat terraces are present at various levels over a distance of eight miles, from the Kaiwhata to the Orui River, and their breadth throughout much of the distance is over two miles. Streams crossing the lower marine terraces have cut broad flat valleys (up to half a mile wide), between which are left the older flat interfluves giving a most complicated series of levels when viewed for the first time. Some of the terraces (the higher levels) are almost certainly marine but the lowest or 30 ft. is undoubtedly of river origin, as will be shown later.
The coastline itself, as before mentioned (p. 510), is now being actively cut back by the sea; the soft Tertiary strata being too incoherent for much undercutting to occur. Slips are frequent, the material being removed by the sea almost as fast as it is supplied. In view of this rapid present-day retreat of the cliffs, the question arises as to what agency or accident has preserved such a wide terrace (two miles wide) along the coast immediately to the rear, for it seems that unless the uplift of 150 ft. was very recent the whole of the terrace should now be cut away. Furthermore, to the north towards Orui, the 150 ft. level is absent but the 350 ft. and 220 ft. platforms, which are not notably developed in the Homewood area, are well exhibited. The explanation apparently lies in the structure of the country.
The rocks strike N.E. and dip inland at angles of 20° to 30°, while the trend of the coast is almost N.E., so that the rocks run out at a slight angle with the coast. Also a reef of very hard rock projects from the headland just to the south of the Kaiwhata mouth. Owing to the state of the sea and tide the writer did not find it possible to examine the reef, but the probability is that it is a hard shell limestone. This reef in former days must have presented a very strong barrier to the sea, as the reef at Castle Point does now, and, although, geologically speaking, such a feature is of only a most
[Footnote] * The name Homewood area is here applied to all that district which lies between the Kaiwhata and Uriti Point.
temporary nature, yet it is certain to leave some effects that will be apparent for a short period after its destruction and it is probably due to the existence of this reef that the erosion of the 150 ft. platform at Homewood has been so long delayed. To the north it is farther from the land (about half a mile to seaward opposite Homewood Station), and as we proceed northward it recedes progressively from the present shore. This is to be expected as that portion would be earlier exposed on the coast and would be attacked first. Thus at Orui, the remnants of the reef are two miles from the shore, and rapid cliff retreat from this former position has completely destroyed the 150 ft. level. The reef may also have aided in the preservation of the 350 and 220 ft. benches when the 150 ft. platform was originally cut at Orui. To-day all that remains of the reef is a few small, upstanding rocks or reefs awash at high water, stretching along the strike of the main reef at the Kaiwhata, and becoming less and less pronounced farther north. In its day, however, it must have presented to the sea a magnificent front similar to that now shown on a smaller scale by the reef at Castle Point.
Furthermore, as will be shown later, a pronounced 30 ft. terrace is present as broad flood plains up all the streams of any size in the district. For all the stream beds to exhibit such marked accordance of a former level, which is so remarkably developed, requires a period of standstill of the strand to be postulated. If such is the case, why is there no record of a marine bench at that height in the district, though such is present further south? If we assume, as indeed there is every reason for so doing, that the sea was engaged at that particular time in cutting back a cliff of hard limestone which retarded its advance very considerably, then the absence of any pronounced bench is accounted for. Since that time it has had only soft Tertiary strata to erode and so has obliterated with ease any marine traces of a period of standstill.
Synopsis of the Terraces in the Homewood and Orui Districts.
(1) At 30 ft.—The terraces in this group are of undoubted river origin. They do not appear as a continuous platform but as a number of flat areas sunk in the general 150 ft. terrace. In plan they are usually horse-shoe shaped, with the open end to the sea. This shape alone makes it practically certain that they are to be ascribed to lateral planation by streams, and not to marine agencies, as the tendency of the sea is to straighten a coastline and not to cut a mile into the land at one place and leave the neighbouring portion untouched, especially when the strike of the rocks is almost parallel to the coast. Moreover, streams in entrenched courses now flow across these plains of lateral planation.
For all the streams to exhibit this 30 ft. plain requires a considerable period of standstill, as many of these basin-like flats are half a mile wide and penetrate a mile or so inland. In some cases two of these plains have coalesced, some distance from the sea, by one stream or other cutting through the interfluve. Both streams, however, still enter the sea on opposite sides of the remaining interfluve
downstream. For this to occur without actual stream capture taking place, both the adjacent plains of planation must have been at exactly the same level when the interfluve was broken down, and the river which obliterated the interfluve must have swung back across its own plain, unless, after capture, the streams separated again. Thus, three miles north of Homewood Station, a broad flood plain is crossed by two rivers which pass to the sea on opposite sides of a remnant of upstanding divide between their mouths, though upstream they appear to flow on the same flood plain. As these remnants are themselves flat-topped (forming part of a higher bench), the effect is to give “hills of planation” somewhat analogous to those described by Gilbert (1877, p. 130). A difference arises in that the flat top on the New Zealand examples may be attributed to marine action in place of normal river planation, the lower, surrounding plain being due to river action alone. These hills are about 50 ft. high (the seaward edge of the older terrace being approximately 70 ft., and the river plain 30 ft.), and form a peculiar feature possible only under the exceptional circumstances described.
The questions arise:—1. Are the higher platforms also plains of lateral river planation? 2. May some of the terraces in other areas be also due to river corrasion?
1. Such forms, when well-developed, may simulate marine terraces so closely as to be indistinguishable and yet the height of a marine bench must be measured at the rear edge, i.e., at the base of the former cliffs, if such are present, while that of a plain of river origin must be taken as near to the sea as possible. Altogether, the problem seems so important that a special section will later be devoted to it (see Appendix p. 520).
2. So far as the raised platforms dealt with in this paper are concerned, the writer considers the 30 ft. Homewood level the only one of undoubted river origin though several others may be taken as of a similar nature.
(2) At 150 ft.—A prominent terrace extends from the Kaiwhata nearly to Uriti Point. This is the widest of all the platforms present, reaching a breadth of over two miles; and, except where crossed by streams and their flood plains, it now reaches the sea-shore; the present cliffs being contraposed in it. The origin of this terrace is somewhat in doubt. The cliffs at the rear are not sharp but are, nevertheless, clearly defined. They are not straight in plan, however, and their general appearance suggests that they were cut by rivers emerging from gorges in the higher terraces. The possibility of such an extensive terrace being cut by small streams is a doubtful point, and the gravels found upon it hardly contribute any definite evidence, though inclining to an alluvial appearance with a suggestion of imbricated structure in an exposure at the side of the road near Uriti Point. The capability of the small rivers which exist in the locality to plane off such a bench is more than doubtful, and the fact that (except for the sharp upwarp at the Kaiwhata end) the inner edge is level for about five miles suggests a marine origin. In the absence of definite evidence the writer inclines to the belief that it is marine.
(3) At 220 ft.—A series of terrace remnants was observed behind the 150 ft. terrace about midway between Homewood and Uriti Point, and an extensive though somewhat dissected platform is present between the Homewood Road and the Orui River. The line of cliffs at the rear is sharp and clearly marked, but the gravel cover is usually obscure. On its general appearance it is classed as marine.
(4) At 350 ft.—In the Homewood District fourteen terrace remnants occur at heights of about 350 ft. Though, owing to the strong dissection of the country, all were not examined, many showed in places a covering of marine gravel similar to that visible on the coast to-day. The deposits range up to ten feet in thickness, and the individual pebbles up to one inch in diameter. Altogether, the alignment of the rear portions and their correspondence in height, together with the character of the gravels seem to indicate a marine origin. At the Orui end, the 350 ft. bench is exhibited as a broad flat top on the hills behind the 220 ft. platform. Like the 220 ft. it is better developed here than at Homewood and it may be here also be regarded as marine.
Whareama River to Okau. (20 miles).
North of the Whareama River, to Castle Point, the soft Plio-Miocene strata (alternating mudstone and sandstone bands a few inches in thickness) outcrop along the coast, forming a series of low cliffs at the foot of most of which is a fringe of present day beach. In many localities there is a prominent “'tween tide” rock platform which is left bare at low water and forms a flat area crossed by slightly raised bands where relatively harder layers outcrop. These “between tide” platforms are sometimes well developed and form a notable feature of this section of the coast. Their prominence may perhaps be attributed to the lack of angular waste with which the sea could abrade them. Another noticeable feature which may also be attributed to the lack of hard waste is that the cliffs are commonly less steep than when cut in hard greywacke. With the reduced cliffcutting efficiency of the sea, and its lag in abrading the bottom, due to the lack of suitable waste before referred to, subaerial weathering becomes more important, and so the cliffs crumble and the angle is prevented from being steepened, while the sea merely pulverises the soft clayey detritus and removes it.
Just to the south of Castle Point, the “'tween tide” platforms are not present but they reappear to the north between Castle Point and Whakataki where the strata can be observed running out on them at a small angle with the coast. A sand beach is also present. To the north of Whakataki, the rock platforms become more prominent than ever and the outcrops in them afford a splendid opportunity for unravelling the structure of the country. (Plate 80. Fig. 2).
Midway between the Whareama and Castle Point is an extensive flat area, in places over half a mile wide and 5 ½ miles long. This may be called the Otahome Flat, after the homestead of that name on it. Though it forms such a prominent feature of the landscape, its origin is a matter of considerable doubt. The only drainage con-
sists of a few small creeks, and the nearest river (the Whareama) is separated from it by a considerable range of hills (the Trooper) in which there is no break to suggest that the river ever flowed nearer Otahome than it does now. Thus a fluvial origin seems out of the question.
On the other hand, the surface, which slopes longitudinally northward from 160 ft. at the Otahome homestead to 90 ft. at its last appearance 1 ½ miles south of Castle Point, is not sufficiently level to be a plain of marine erosion. Furthermore, no trace of marine gravel has been found upon it. (This, however, may be attributed to the softness of the rocks, the absence of typical beach deposits being merely due to the rock crumbling, instead of forming pebbles, and giving a deposit now indistinguishable from residual clay produced by subaerial weathering). Again, there is a noticeable absence of cliffs, or any suggestion of cliffing, at the rear of the platform. Once more this may be attributed to the softness of the country rock, which rapidly disintegrates with the loss of all bold lines in the topography and the production of rounded contours. There is thus considerable difficulty in determining the origin of the Flat, but for the present it may be regarded as marine.
At Castle Point a number of even crested ridges occur but there is no justification for attributing their form to marine agencies, especially as their heights are discordant.
The lighthouse reef at Castle Point is of interest, not only as a fossil locality, but also as a physiographic study. The structure is simple. The Plio-Miocene sedimentaries run out at small angle with the coast and dip inland at 15°. A hard band of limestone has produced a resistant barrier to the sea and caps a small sea cliff which rises northward. At the north end arenaceous deposits form the uppermost layer (on which the lighthouse is built) but at the seaward edge these have been cut away by the spray which dashes with great violence against them as the waves strike the limestone below. A stripped upper surface is thus produced on the limestone which therefore stands seaward as a platform sloping slightly inland. Behind the reef is a lagoon, which has an opening to the sea at the south end, where the limestone stratum inclines down towards sea level. Along the outer margin of the reef the finest marine views on the coast may be obtained in rough weather, the sea dashing with great violence against the almost vertical surface of the limestone and hurling spray high in the air against the arenaceous deposits behind. Beneath the lighthouse a large cave pierces completely through the reef. Due to percolating waters much travertine has been deposited in it and small stalactites hang from projections on the roof.
It requires little imagination to visualise a reef such as this, on a much grander scale, previously protecting the Homewood coast north of the Kaiwhata; and the existence of such a reef in former times in that region has already been discussed.
For some distance along the Matai Kona Road, north of Whakataki, a series of roughly stratified sand deposits containing Recent marine Mollusca occurs. They may possibly represent a period of
standstill when the strand was 50 ft. higher than now or may be correlated with the Recent mudstone deposits and Kaiwhata conglomerate of the Homewood area. In the latter case the movement may have been almost uniform along the coast and the intervening evidence eroded away. There is, however, no definite basis of correlation.
The Correlation of Platforms in Different Areas.
It seems advisable here, in view of the fact that excellent suites of platforms occur only in widely separated localities, to give a summary of the bases on which these suites may best be correlated, if any such correlation is possible.
1. Similarity in height.—If uplift movements were uniform from place to place it would be possible to correlate benches in different localities on the evidence of height alone. Furthermore, if only a slight tilt or warp is present, and the sets of benches not very far apart, calculations of slopes and gradients can be used as a basis of correlation. This method was employed herein with the benches along the east side of Palliser Bay where the gaps between sets of terraces are not great and where all the terraces have a general slope to the north. It is frequently necessary, however, to treat each platform in one vertical set separately to allow for the effects of warping or tilting in between the various stages. This method has proved of great service when employed over limited areas but is insufficient in itself when applied to benches in widely separated localities.
Jobberns (1928) in his study of the north-east coast of the South Island, found practically continuous marine terraces for considerable distances along the coast at almost constant elevation and used a pure height correlation very extensively in comparing benches in different areas. It must be emphasised, however, that his is an exceptional case and well supported by field evidence of almost strictly uniform uplift. In the southern portion of the North Island benches are rarely found parallel to sea level but are strongly tilted and warped. Any correlation based on actual height is therefore not only useless but misleading.
Henderson (1924, p. 589) bases most of his correlations purely on height data, and divides the benches of the New Zealand coast into four groups: (a) Awakino Cycle, up to 120 ft.; (b) Tongue Point Cycle, 200-300 ft.; (c) Charleston Cycle, 350-600 ft., and (d) Kaukau Cycle, above 600 ft.
This arbitrary division on such a basis, though it may be true in a broad sense for New Zealand as a whole, cannot be applied to a limited area because a continuous tilted platform may, at one extremity, fall well within the limits of one group and at the other end be quite as definitely comparable in height with the representatives of a much younger or older cycle. Thus Terawhiti 125 ft. platform would approach most closely the Awakino Cycle, while the Tongue Point 240 ft. platform, a continuation of the Terawhiti platform, is actually the type locality of the earlier Tongue Point Cycle; also the second Terawhiti remnant (250 ft.) is, according to the height correlation, of Tongue Point age, but its equivalent, the
Tongue Point upper remnant is 480 ft., and therefore to be classed with the Charleston platforms. Again, the main platform of the east side of Palliser Bay is, at its southern extremity, 700 ft., and therefore should be equivalent to the Kaukau Cycle, while at Te Hamenga and Waitarangi it is 600 ft. and 545 ft. respectively, thus being definitely within the limits of the Charleston Cycle.
It seems, then, that strict correlation of platforms on the basis of height alone is attended by very grave dangers of error. Admitting that in the broad sense New Zealand has moved as a whole during late Tertiary and Recent times, yet differential movement has also been strong in some localities, and the complications arising from the correlation of benches which, though at similar levels, are nevertheless of different age are likely to become formidable if height data are relied upon exclusively.
Furthermore, many of the earlier estimates of terrace levels are merely eye measurements, and it is extraordinarily difficult, even with constant practice, to judge the heights of terraces with any degree of accuracy. Jobberns (1928, p. 531) records an instance where an estimated height (by Hutton) was “only a little more than half the actual height.” McKay also erred in the same direction in his estimates of the Palliser Bay benches. In consequence, therefore, of the excessive warping and tilting of the platforms under review no correlations on height alone are attempted here.
2. Similarity in stages of development and appearance.—In some cases this forms a very reliable guide for the classification of terraces. A better example could hardly be found than the profiles of Terawhiti and Tongue Point. In spite of the disparity in heights previously referred to, a comparison of the profiles renders correlation almost certain, and in this case there is the continuous presence of the lower platform between the two points to place the identity beyond doubt. It was found in the field that by this method, the comparison of sets of benches was not only much simplified but also fairly reliable. The relative extent of successive terraces, combined with their relative heights, gives a general impression of them which is of the utmost value for correlative purposes. A precaution which must be observed lies in noting the geological structure of the country, as in different sets of beds quite different appearances may be assumed by the same platform. Notably the ratio of height to width varies.
3. The covering beds.—In some instances a characteristic rock type may be found among the deposits on a certain bench but not on the terraces either above or below. Fragments of rotted pumice, for example, may be frequently found on a particular terrace and so provide a guide to the correlation of platforms in neighbouring areas. As a general rule, however, the character of the rocks and pebbles forming the cover varies so considerably (a) with the distance transported and (b) with the rock of which they are composed that a small distance may be responsible for a great change in the type of cover, especially when the beds were deposited close to the supply of waste.
A tentative correlation of the benches of the South Coast is here given. In each case two benches are very prominent, all others being
distinctly subsidiary, and in every locality the lower of the two more prominent platforms is the better developed. They are therefore taken as the basis of correlation from district to district.
|Terawhiti.||Tongue Point.||Baring Head.||Orongorongo.||Black Rocks.|
|—||—||—||925 ft.||965 ft.*|
|250 ft.||480 ft.||760 ft.||870 ft.||950 ft.|
|—||—||Two small terraces.||—||—|
|125 ft.||240 ft.||385 ft.||480 ft.||700 ft.|
From this it will be seen that the two main terraces, which are found in each case, correlate fairly well, rising in each instance the farther east that they appear, suggesting a general axis of tilting somewhere in Cook Strait. Just as the Tongue Point shoreline is downwarped in Port Nicholson at the present day, so, apparently, there was warping between previous uplifts producing slight anomalies in the relative heights. In every case the platforms are carved in hard greywacke.
The terraces of the Homewood area, excavated in soft Tertiary strata, present features not comparable with those cut in greywacke and have been already correlated among themselves so that no attempt is made as yet to compare their various ages with those of the greywacke suite.
Correlation of lower raised beaches.
Beaches at 25 ft. to 35 ft.—This is present from Baring Head to Orongorongo, whence it follows around Cape Turakirae and appears as the wide 25 ft. beach along the west side of Palliser Bay. Where the Tertiary rocks outcrop at the head of the Bay it is now entirely cut away by the sea operating at its present level, but is prominent farther on as the 35 ft. uplifted plain fringing the coast from Waitarangi to the Pahaoa. Farther north, it is probably represented in part by the prograded coast south of Flat Point and then by the 30 ft. uplift at Homewood and the Kaiwhata. Thus one of the latest movements of the coast appears to have been a general uplift of approximately 30 ft. throughout almost the whole length of coast described in this paper.
Criteria for the Determination of Marine or Alluvial Origins.
In any discussion involving quantitative estimations of uplift, the origin of the particular terrace on which calculations are based must of necessity be one of the most important points to be deter-
[Footnote] * The 965 ft. bench is not at Black Rocks but at Te Hamenga; this is equivalent to a height of 1060 ft. at Black Rocks Point.
mined, for, in the case of a marine terrace the previous shoreline must have been at the rear edge of the terrace, where a line of cliffs may or may not be present; whereas an alluvial plain must be measured at its seaward edge for the bed of a stream near the sea is practically at sea level and if the stream be well graded, as indeed it must be to produce a plain of any dimensions, then we may take that height nearest the sea as giving us the best measure of uplift. To quote an instance: the platform at Homewood whose height has been given in a previous section as 30 ft. has a height at the rear edge of 100 ft. Thus if, by any mischance, it were classed as of marine origin, then the uplift represented would be over three times the real measurement. The importance, then, of correct determinations cannot be over-estimated and it is with the object of explaining the criteria employed in the field work for the present paper that the following remarks are appended.
1. General appearance, extent, position and relative proportions of the terrace.—These are all qualities to be observed from one suitable standpoint, and usually provide the strongest impressions that one receives. The surface must be considered, whether it is even or irregular, whether any irregularity is due to unconsumed stacks, to slipping of the covering beds, or to disused stream channels. A finely sinuous rear edge to a terrace may be taken as indicative of a river origin just as a straight or gently curved one implies a marine origin. In this connection it should be noted that the inner edge of an uplifted terrace is commonly rather more embayed than is the later coastline. Generally speaking, the greater the distance along a coast through which a terrace extends the greater are the possibilities that it is marine, as few New Zealand rivers flow parallel to the coast for a considerable distance. Broad terraces facing the sea near the mouths of even small rivers are always open to grave doubt, especially if no terraces are found farther along the coast, for, though originally cut by one agency, they may be subsequently modified with ease by the other.
2. Character and distribution of the covering deposits.—Discoidal gravels are not always found in beach deposits, indeed they are exceptional, but beach gravels are commonly better sorted and less bound together with fine material than are their alluvial equivalents and with practice a nice discrimination between the two types can be made in the field. Apart from the composition of covering deposits much information may be obtained from a consideration of their distribution. For example, at the mouth of the Conway River, South Marlborough, the terrace now uplifted 40 ft. above high water mark is crossed parallel to the present shoreline by a series of gravel ridges formed during the retreat of the sea and proving the marine origin of the terrace. (Jobberns, 1928, p. 532). The remains of former dune deposits may also throw light on earlier shorelines. If the character of the gravel only is relied on, it must be borne in mind that a bench may be river cut, depressed and covered by marine gravel.
3. The slope of the rear edge of the terrace.—No river cut terrace will exhibit a perfectly level inner edge if followed along parallel
to the coast, unless it has been tilted back through exactly the angle at which it was cut. This case is extremely improbable, and so level terraces must be, almost without exception, marine.
4. Presence or absence of cliffing at the rear.—Good cliffing seems to be more characteristic of the marine type, though river cut terraces sometimes exhibit quite sharp cliffs.
5. Presence of “island” interfluves, as described earlier in this paper, is always indicative of a stream origin, on an uplifted coast.
6. Marine shells have been recorded from some raised coastal terraces though they are not of frequent occurrence.
Broadly speaking, the coastline, throughout the length examined, is a coastline of emergence, the only exceptions being Port Nicholson (a local downwarp) and Palliser Bay (a fault angle depression). Along much of the distance uplifted terraces of undoubted marine origin testify to the amount of uplift from place to place and demonstrate that the movements were not uniform but consisted of a series of interstage warpings and tiltings. Small movements of subsidence have also taken place within comparatively recent times at the Kaiwhata and may have affected other regions, but no definite evidence in support of a general lowering of the land was obtained.
Adkin, G. L., 1919. Further Notes on the Horowhenua Coastal Plain, Trans. N.Z. Inst., vol. 51, pp. 108-118.
— 1921. Porirua Harbour, Trans. N.Z. Inst., vol. 53, pp. 144-156.
Aston, B. C., 1912. The Raised Beaches of Cape Turakirae, Trans. N.Z. Inst., vol. 44, pp. 208-213.
Bartrum, J. A., 1916. High Water Rock Platforms, Trans. N.Z. Inst., vol. 48, pp. 132-134.
— 1927. The West Coast of Firth of Thames, Trans. N.Z. Inst., vol. 57, pp. 245-253.
Bell, J., 1910. The Physiography of Wellington Harbour, Trans. N.Z. Inst., vol. 42, pp. 534-540.
Cotton, C. A., 1912. Notes on Wellington Physiography, Trans. N.Z. Inst., vol. 44, pp. 245-265.
— 1914. Supplementary Notes on Wellington Physiography, Trans. N.Z. Inst., vol. 46, pp. 294-298.
— 1916. The Structure and Later Geological History of New Zealand, Geol. Mag., dec. 6, vol. 3, pp. 243-249; 314-320.
— 1916a. Fault Coasts in New Zealand, Geogr. Rev., vol. 1, pp. 20-47.
— 1918. The Outline of New Zealand, Geogr. Rev., vol. 6, pp. 320-340.
— 1921a. For how long will Wellington escape Destruction by Earthquake? N.Z. Journ. Sci. & Tech. vol. 3, pp. 229-231.
— 1921b. The Warped Land Surface on the South-eastern Side of the Port Nicholson Depression, Wellington, Trans. N.Z. Inst., vol. 53, pp. 131-143.
— 1922. The Geomorphology of New Zealand, Govt. Printer.
Crawford, J. C., 1855. Geology of the Port Nicholson District, N.Z., Journ. Geol. Society, vol. 11, p. 530.
Crawford, J. C., 1868. The Geology of the North Island of New Zealand, Trans. N.Z. Inst., vol. 1, separately paged.
— 1869. The Geology of the Province of Wellington, Trans. N.Z. Inst., vol. 2, p. 350.
Daly, R. A., 1921. Post Glacial Warping of Newfoundland and Nova Scotia, Amer. Journ. Sci., vol. 1, pp. 381-391.
— 1925. Pleistocene Changes of Level, Amer. Journ. Sci., vol. 5.
Gilbert, —, 1877. Geology of the Henry Mountains, Washington.
Henderson, J., 1924. The Post Tertiary History of New Zealand, Trans. N.Z. Inst., vol. 55, pp. 580-599.
Jobberns, G., 1926. Raised Beaches in the Teviotdale District, North Canterbury, Trans. N.Z. Inst., vol. 56, pp. 225-226.
— 1928. The Raised Beaches of the North-east Portion of the South Island of New Zealand, Trans. N.Z. Inst., vol. 59, pp. 508-570.
McKay, A., 1878. Report on the East Wairarapa District, Rep. Geol. Expl. N.Z.G.S., vol. 11, pp. 14-24.
— 1879. Report on the Southern Part of the East Wairarapa District, Rep. Geol. Expl. N.Z.G.S., vol. 12, pp. 75-85.
— 1884. On the Igneous Rocks of the East Coast of Wellington, Rep. Geol. Expl. N.Z.G.S., vol. 16, pp. 71-75.
McKay, W. A., 1899. Geology of the Trooper Range, Castle Point District, Mining Reports, Parliamentary Papers, C9, 1899, pp. 33-36.
— 1899. Geology of the East Coast from the Kaiwhata River to Glenburn, East Coast of Wellington, Mining Reports, Parliamentary Papers, C9, 1899, pp. 36-43.
— 1901. Geology of Cook Strait from Pencarrow to the Ruamahanga River, Mining Reports, Parliamentary Papers, C10, 1901, pp. 28-33.
Marshall, P., 1927. The Wearing of Beach Gravel, Trans. N.Z. Inst., vol. 58, pp. 507-532.
— 1929. Beach Gravels and Sands, Trans. N.Z. Inst., vol. 60, pp. 324-365.
Morgan, P. G., 1922. Limestone and Phosphate Resources of New Zealand, pt. 1, Limestone, N.Z.G.S. Bull., No. 22.
Park, J., 1910. Some Evidences of Glaciation on the Shores of Cook Strait and Golden Bay, Trans. N.Z. Inst., vol. 42, pp. 585-588.
Physiographic Features of the Lower Cascade Valley and the Cascade Plateau, South Westland.
[Read before the Otago Institute, 8th July, 1930; Received by Editor, 23rd July, 1930; issued separately, 25th November, 1930].
Outline of Topography.
The Conglomerate Series.
Physiographic Features of the Cascade Plateau.
Origin of the Cascade Plateau.
Glaciation in the Cascade, Martyr and Jackson Valleys.
List of Literature.
Outline of Topography.
The area under discussion is a belt of rugged hill and mountain country in southern Westland, lying between the Arawata, Jackson and Cascade Rivers, and bordered on the north by the sea coast. It has twice been visited by the writer during the last two summers, when the following observations were made.
Of the three rivers mentioned above, the Arawata is the largest, swiftest and most formidable. It heads against the Main Divide among the glaciers and ice-fields of the Barrier Range, and the high country in the vicinity of Mt. Aspiring. Its tributary; the Jackson, rises at the north-eastern end of the Olivine Range on the slopes of Mt. Collyer, and, for the greater part of its extent, follows a rectilinear north-easterly course to the Arawata, which it joins about five miles in from the sea.
The Cascade is also a large, swift river, but normally does not carry as much water as the Arawata, since its source lies west of the Main Divide in the vicinity of Red Mountain, where the permanent ice-fields are not so extensive as further east. The river flows through a series of steep-walled gorges with a well marked, general north-easterly trend, which is especially pronounced for a distance of eight or ten miles below McKay Creek, where it continues the north-easterly line of the Jackson Valley. Twelve miles above its mouth the river emerges from the gorge between the Olivine and Hope-Blue River Range and, swinging abruptly through a great bend of 90°, follows a meandering north-westerly course down a wide, alluviated valley to the sea (Pl. 81, Fig. 3; Pl. 82, Fig. 4). Its three tributaries—Martyr, Woodhen and McKay Creeks—occupy deep and precipitous gorges which dissect the western slopes of the Olivine Range (Pl. 81, Fig. 2; Pl. 82, Fig. 5).
This latter is the chief mountain range of the district. It branches in a north-easterly direction from the north end of the Humboldt and the south end of the Barrier Range, and for many miles constitutes the watershed between the Cascade and Arawata Rivers. At its southern end the peaks attain a height of 7,000 ft., but further north-east the range seldom rises much above 5,500 ft. The south-eastern sides and summit of the Olivine Range consist of chlorite-epidote-albite-schist and quartz-muscovite-schist similar to the
schists of Central Otago, but its western slopes are carved in the great intrusive mass of peridotite which extends from the Jackson River in the north to Red Mountain and the Red Hill Range in north-west Southland (Turner, 1930).
The Hope-Blue River Range, which lies west of the middle portion of the Cascade Valley and parallel with the Olivine Range, constitutes a belt of densely forested country rising to a little above
4,000 ft., the seaward side of which is drained by the Hope River. The country between the Jackson River and the coast is of a similar nature, and, like the Hope-Blue River Range, consists of gneiss and hornfels invaded by granite-pegmatite (Turner, 1930, p. 174).
Possibly the most striking topographic feature is the Cascade Plateau which borders the Cascade Valley on its northern side for a distance of ten miles in from the sea coast, and extends westward for several miles to Carmichael Creek. This feature will be described and discussed fully in a later section.
The Conglomerate Series.
In a previous paper (Turner, 1930) an account has been given of the metamorphic and ultrabasic rocks of the Lower Cascade Valley. These constitute a basement upon which lies unconformably a great series of bedded clastic rocks—mainly coarse, well-cemented conglomerates—derived from the erosion of the underlying formations. These younger rocks are here grouped together as the Conglomerate Series, the origin of which is closely connected with the early stages in the physiographic development of the Cascade Valley.
Rocks of this type, sometimes containing boulders as much as four feet in diameter, are exposed abundantly along the old track, between the bridge across the gorge of Martyr Creek and the ford where it crosses the same stream, about four miles below. The constituent boulders are imperfectly rounded and are set in a hard cemented matrix of fine blue clay (Pl. 81, Fig. 1). The majority consist of fairly fresh peridotite derived from the rocks of the Olivine Range, though masses of gneiss, schist and hornfels also are present. In this locality the gneissic basement is not far beneath, and outcrops from under the mantle of drift in the gorge of Martyr Creek and at intervals along the track. McFarlane, who, in 1877, first explored the Cascade Valley, took advantage of the creek being unusually low to follow down the Martyr Gorge. He notes (1877, p. 30) that “the river having cut clear through to a depth of 150 feet in places, a fine section of the formation is presented, which consists of a heavy conglomerate showing very complete stratification, having a very slight dip to the north-west.”
Cemented conglomerate was also observed along the southern slopes of Red Spur, where it falls away steeply into the valley of Martyr Creek (Pl. 81, Fig. 2). It is exposed, almost from the level of the creek to a height of over 1200 ft. above sea-level, in the bed and walls of a narrow gorge leading down from Red Spur. Although here it directly overlies peridotite, the component boulders of the conglomerate are mainly schist—probably derived from the tract of schist country in which the Martyr rises. This fact and the highly indurated state of the rock preclude any possibility of its being simply a hillside talus.
The rocks of the Conglomerate Series attain their most extensive development on the north-eastern side of the lower part of the Cascade Valley, where they underlie the whole of the Cascade Plateau, an area of about 20 sq. miles. The surface of the Plateau is itself
largely covered with a mantle of glacial moraines, the origin of which will be outlined later in this paper. A fine section is exposed in the gorge of Teer Creek, which is the only large stream to cross the plateau. It rises in the ranges to the south-east and cuts north-west across the plateau through a profound gorge about 1,000 ft. in depth. This was crossed at two points, respectively three miles and one mile above the mouth.
At the first of these, conglomerate outcrops in perpendicular bluffs at intervals between the stream bed (possibly 200 ft. above sea-level) and a height of about 1,200 ft. or more. The boulders are large and consist mainly of gneiss, hornfels and schist, to the almost complete exclusion of peridotite.
At the second point, one mile above the mouth of the creek, hard blue mudstone is exposed in the stream bed and is overlain upstream by conglomerate, consisting of subangular but partially rounded boulders set in the usual matrix of hard blue clay. Here again peridotite is rare. There is a regular dip upstream (i.e. south-east) at about 5°. On the west side of the creek, at a considerable height above the bed, steep bluffs are cut in massive mudstones about 100 ft. thick, through which run occasional thin bands containing subangular boulders. These pass up into conglomerate, which appears to continue to a height of about 1,000 ft. or 1,100 ft. above sea-level. Immediately west of this, in the bed of the tributary marked A (Text-figure 3), similar conglomerate is again exposed not more than 200 ft. below the general plateau level, i.e. between 900 ft. and 1,000 ft. above sea-level.
The above observations indicate beyond doubt that the unconsolidated morainic material which covers most of the plateau is actually a relatively thin cover, beneath which lie at least 1,000 ft. of rocks belonging to the Conglomerate Series. Observation of conglomerates in the gorge of Laschelles Creek, and reports regarding exposures in the sea cliffs along the northern margin of the plateau lend support to this conclusion.
Cox (1877, pp. 94, 95) has described strongly folded Tertiary sedimentary rocks, lithologically very different from the Conglomerate Series, from the vicinity of the old settlement at Jackson's Bay, about five miles east of the edge of the Cascade Plateau. It may safely be assumed that the contorted state of these strata is due to the great earth movements of the Pliocene which Cotton has termed the Kaikoura deformation. It follows, then, that the almost undisturbed strata of the Conglomerate Series were most probably laid down subsequently to this movement, and their age cannot in that case be earlier than late Pliocene.
On the other hand, the well cemented nature of the conglomerates and mudstones, their regular stratification, and the slight inclination of the strata (north-west in the gorge of Martyr Creek and south-east in Teer Creek) all point to a pre-Pleistocene age. Morgan (1928) and Marwick (1928) both regard the Pleistocene of New Zealand as a period of extensive glaciation comparable and contemporaneous with the European Pleistocene, and uphold the principle that, in the rocks of the South Island, the Pleistocene-Pliocene boundary should be
Fig. 1.—Conglomerate, ¼ ml. west of Martyr Bridge, Cascade Valley. [G. J. Williams photo
Fig. 2.—Red Spur and the valley of Martyr Creek, seen from the crest of Martyr Spur. The light coloured area, bare of vegetation, is peridotite, while the forested area to the right is underlain by schist. [J. S. Thomson photo.
Fig. 4.—The lower portion of the Cascade Valley, seen from the end of Martyr Spur (500 ft), looking Seawards The Cascade Plateau forms the sky-line on the right and in the middle of the photograph, while on the left are seen the lower spurs of the Hope-Blue River Range. [G. J. Williams photo.
Fig 5—Mt. Richards and the gorge of Woodhen Creek, seen from the peridotite-schist junction on the crest of Martyr Spui (4,000 ft) Note the bare peridotite in contrast with the bush-covered schist on the left The snow-covered peaks beyond Mt Richards are the summit of the Olivine Range [G. J. Williams photo
Fig. 8—Eastern boundary of the Cascade Plateau near the head of Teer Creek, looking northward On the right is the spm leading up to Colin Hill, while the gorge of Teer Creek cuts-across the middle of the photograph from right to left [J A. Bartrum photo.
Fig. 10.—Regular marginal moraine, forming a sharp ridge 1 ½ mis. long, ¾ ml. north-west of Twin Blocks Trig., summit of Cascade Plateau. Note the meandering course of the stream. Photograph taken looking north-west [J. A. Bartrum photo.
Fig 11—Regular morames on the north-eastern side of the valley shown in Fig 10, summit of Cascade Plateau The almost horizontal line AB is the erest of the ridge marked × in Text-Fig. 3 Beyond it lies another inter-morainic valley, the drainage from which reaches the main valley through an incipient break in the ridge AB, just to the left of A. Note the difference between the height of AB and that of the ridge CD beyond. [J. A. Bartrum photo
Fig 12—Surface of moraine at Twin Blocks Trig Station, summit of Cascade Plateau. The two large blocks are hornfels, the smaller boulders in the foreground being peridotite [J. A. Bartrum photo
Fig 13.—Junction of streams B and C (Text-Fig 3), summit of Cascade Plateau, looking north-east The line × Y Z is the erest of a regular moraine, beyond which lies the deep gorge of Teer Creek The streams in the foreground reach the latter through the gap Y The even surface of the Plateau east of the gorge constitutes the sky-line [J. A. Bartrum photo.
Fig 14—Southern end of the Cascade Plateau, as seen looking north from the Cascade Hut, Cascade Valley On the right is the mouth of Laschelles Creek [J. A. Bartrum photo.
Fig 15—Looking north-west into the valley of the Cascade River, from the margin of the Cascade Plateau, west of Twin Blocks Trig Station The floor of the valley is hidden in mist, but commencing from the point A, the edge of the lateral moraine which constitutes the teriace at 1,350 it above sea-level, is clearly visible, merging gradually into the surface of the plateau in the distance. [J. A Bartrum photo
drawn at the base of the earliest deposits of glacial origin. There is no reason to suppose that the Conglomerate Series of the present area represents outwash from Early Pleistocene glaciers. On the contrary, as will be shown later, two series of moraines are definitely known to post-date the deposition and uplift of these rocks.
The Conglomerate Series is therefore regarded as being of late Pliocene age.
From the foregoing description it will be seen that the rocks of this series are limited to areas bordering the Cascade and Martyr Valley, where they occur between sea-level and a height of about 1,200 ft., and are entirely absent from the higher slopes of the adjacent ranges. It follows, therefore, either that the conglomerates originally had a wider distribution, and owe their present limited extent to preservation from erosion in down-faulted areas, or else that they were deposited in a late Pliocene valley, the site of which is still occupied by the Lower Cascade and Martyr Rivers. The field evidence strongly supports the latter view. The writer, therefore, suggests that, towards the close of the Pliocene, a wide triangular depression, probably the result of erosion along lines determined by faulting in the Kaikoura Orogeny, extended across the area which to-day is occupied by the Cascade Plateau and the lower portion of the Cascade Valley. This depression narrowed inland, and continued southward some distance beyond the present great bend in the Cascade River, along the line of what is now the valley of Martyr Creek. As a result of long-continued slow sinking of the land, alluvial gravels, and to a less extent finer sediments, together with pluvial and talus debris, accumulated continuously at the foot of the ranges.
In this way a thickness of over 1,000 ft. of strata was built up. When eventually this phase of slow subsidence and accompanying deposition of gravels came to a close, the land surface must have consisted of dissected mountain-ranges bordering a broad infilled depression, the surface of which sloped gently seaward to sea-level at the coast. The present elevation of the remnants of this ancient surface indicates that at this time the land stood considerably lower (possibly 1,000 ft.) than to-day.
Physiographical Features of the Cascade Plateau.
Between the mouth of the Laschelles Creek and the sea coast the north-eastern wall of the Cascade Valley rises steeply from only a few feet above sea-level to the summit of the Cascade Plateau (Pl. 86, Fig. 14). This is an extensive triangular tableland, about 20 sq. miles in area, which stretches between the Cascade Valley and the eastern side of the Carmichael Creek. At its highest point—Twin Blocks Trig. Station, just above the gorge of Laschelles Creek—it reaches an elevation of 1,900 ft. above sea-level, and thence slopes gently northward to a height of between 800 ft. and 1,100 ft., where it terminates in lofty and precipitous cliffs along the sea coast. This seaward slope is very noticeable as seen from the floor of the Cascade Valley or the lower spurs of the Olivine Range, whence the plateau presents a remarkably even profile in striking contrast with the
ragged sky-line of the adjacent mountain ranges (Pl. 82, Fig. 4). On its eastern border the regular surface of the plateau terminates abruptly against the steep, heavily-bushed slopes of the spurs leading up to Colin Hill and Mt. Alpha (Pl. 83, Fig. 8).
As shown in the previous section, the Cascade Plateau is everywhere underlain by a great thickness of late Pliocene conglomerates. The surface, however, is covered—probably to a depth of over 300 ft. in some places—with unconsolidated moraine. It is littered with large boulders (Pl. 82, Fig. 6) which average about 3 ft. to 4 ft. in diameter, but which frequently are much larger (Pl. 85, Fig. 12) and may even attain 20 ft. or more in average dimension. The majority consist of fresh dunite, wehrlite and harzburgite brought down from the Olivine Range (Turner, 1930, p. 190), but hornfels and schist are also represented (Pl. 82, Fig. 7). As on the peridotite belt itself, the surface is bare of vegetation, except for tussock grasses, rushes, and patches of low scrub, but in the gorge of Teer Creek, where the underlying conglomerates are exposed, the steep slopes are heavily bushed.
Though the plateau appears from below to be regular in the extreme, in reality this is by no means the case; for its surface, upon actual examination, is seen to have a complex and strikingly unusual drainage system, the main details of which are sketched in the accompanying map (Text-Fig. 3). In the north-western corner the major features only are indicated, since the time available was not sufficient to map the whole plateau in detail.
The most important drainge channel is Teer Creek, which rises in the bush-covered hills to the south-east and cuts north by west across the plateau, through the deep gorge described in an earlier section. On either side, the gorge is flanked by a well-defined terrace about 100 ft. below the general level of the plateau, and this appears to represent a bench, where the cemented rocks of the Conglomerate Series outcrop from under the morainic cover.
All the streams west of Teer Creek, including the tributaries of Teer Creek itself, have several striking peculiarities in common. In the first place their valleys and the intervening ridges show perfect parallel disposition along a distance of from five to ten miles. This trend of the topography, though roughly north-west, in reality varies round the are of a circle, between north, at the southern vertex of the plateau, to almost due west at its north-western corner in the vicinity of Cascade Point. Again, the floors of the valleys are without exception only about 100 ft. or 200 ft. below the general level of the plateau, along the greater part of their extent. The cross-profile is typically V-shaped, though sometimes, as in the case of Creeks B and C, the valley floor may be nearly flat for a width of a quarter of a mile or more (Pl. 85, Fig. 13).
The tributary streamlets are in every case parallel to the major drainage channels; and junction between the two is effected by the tributary turning sharply at right angles to its former course, and cutting through an incision in the intervening ridge. In such cases, it will be noted that the trend of the tributary is usually continued beyond such an outlet, by another stream flowing in the opposite direction (e.g. stream B continuing the trend of stream C).
Origin of the Cascade Plateau.
It might at first sight be suggested that the regular drainage pattern of the surface of the Cascade Plateau is the result of the establishment of consequent streams, flowing down the slope of an uplifted, slightly tilted plain. There are, however, a number of striking and persistent peculiarities, which cannot be explained on the assumption that we are dealing with normal valleys of erosion. These may be outlined briefly as follows:—
(1) The regular sweep of the drainage trend, from north almost to due west, is not in accordance with the due northerly slope of the plateau surface. (The latter has been verified accurately from the surveyed heights of a number of trig. stations at various points on the plateau).
(2) Though the drainage channels have the typically V-shaped cross-profile of the juvenile valley of erosion, the streams themselves are sluggish, and show on a small scale a perfect system of meanders across a narrow belt only four or five yards in width (Pl. 84, Fig. 10). In some cases even there are swamps and small lakelets at the confluence of two or more such streams.
(3) Though the morainic material comprising the intervening ridges consists of boulders of all sizes, yet there is no concentration of the larger masses towards the valley floors, such as must certainly have taken place if steep-walled valleys had been cut in unconsolidated moraine.
(4) The valleys and ridges are unusually closely spaced.
(5) In some cases the summit of a ridge, though regular and obviously not reduced by erosion, may lie from 20 to 50 ft. below the summits of the adjacent ridges (Pl. 84, Fig. 11).
(6) In almost every case the ridges are covered with boulders of peridotite, amongst which masses of schist and gneiss occur to the extent of only about 5 per cent. Nevertheless a single minor ridge (X, Text-Fig. 3), about 400 yds. in length, was found to consist almost entirely of blocks of foliated schist, similar to the distant schists that crown the Olivine Range. In this case, the streams on either side of the ridge × form sharp lines of separation from the adjacent peridotite-covered ridges on either side.
The only hypothesis which will readily explain the above facts is that the plateau is an elevated plain, the surface of which is covered with an immense series of regular, parallel marginal moraines, the spaces between which now act as drainage channels. These moraines have for the most part been but little eroded, since, with the exception of the deeply entrenched Teer Creek, the intervening streams do not rise beyond the confines of the plateau, and hence have little erosive power. Whereas the general uniformity of the plateau surface is due to the fact that the morines have accumulated upon an ancient uplifted plain, the present curious drainage pattern is due to the disposition of the overlying moraines themselves. The writer, therefore, offers the above suggestion as the solution to the problem.
If this solution is accepted, it is easy to picture the material composing the ridge × in Text-Fig. 3 (Pl. 84, Fig. 11), as a small
moraine brought down to the main ice-sheet by some tributary glacier, heading back into the schists of the Olivine Range. The hummocky topography developed round the point Y (Text-Fig. 3), not far from the source of Dougal Creek, also lends support to the idea that the original moraine topography has not been materially altered by post-Glacial erosion.
On its south-western flank the steep slope of the plateau, where it falls away rapidly into the Cascade Valley 1,800 ft. below, is broken by rather narrow, well-defined terraces at heights of 1,350 ft., 750 ft., 450 ft., and 400 ft. above sea-level. Characteristically each terrace is bounded along its inner margin by a streamlet running parallel to the terrace edge about 30 ft. below the terrace level. The uppermost, as seen from the summit of the plateau, is almost horizontal, and bends regularly north-west along the are of a quarter-circle, until ultimately it intersects the sloping surface of the plateau, and blends into the regular parallel sweep of the surface moraines (Pl. 86, Fig. 15). South of the plateau it is continued as a gently sloping terrace on the flank of the high hills between Laschelles Creek and the Jackson-Martyr Saddle. The above facts, taken in conjunction with the fact that the terraces seem to be made up largely of peridotite boulders, indicate that the terraces are probably of glacial origin, and are to be regarded as the lateral moraines of the ancient Cascade Glacier.
The physiographic evolution of the Cascade Plateau may be summed up briefly as follows:—
At the close of the Pliocene, after the in-filling of the Cascade Depression, elevation of the land, possibly by 800 ft. to 1,000 ft., accompanied by very slight warping, took place. The ancestral Cascade River cut down rapidly through the uplifted rocks of the Conglomerate Series, and became incised in a deep valley, approximately along its present course, flanked on the north-east by an uplifted plain—the Cascade Plateau.
Closely following this came the Pleistocene glaciation. A large glacier flowed down the Cascade Valley, the lower and wider portion of which must have become filled with slow-moving ice. Eventually, as the glacier increased in volume, the ice, which further upstream was hemmed in by lofty mountain walls, appears to have spilled over the valley rim upon the surface of the plateau, across which it pushed out an extensive ice-lobe, which stretched to its eastern and northern boundaries, and so possibly reached the sea coast. During the slow retreat of the ice-front in the later part of the Pleistocene, an immense series of parallel marginal moraines accumulated, marking intermittent periods when the ice neither advanced nor retreated. Further shrinkage of the ice resulted in its withdrawal from the surface of the plateau, though a very large glacier still occupied the valley below. It was at this stage that the lateral moraines, which now form terraces along the north-eastern wall of the Lower Cascade Valley, were deposited by the slowly sinking glacier.
Teer Creek was probably a well-established stream by the time the ice first spread across the plateau, but its gorge has doubtless been deepened considerably since the covering ice sheet withdrew. Otherwise, the only modification of the plateau in Recent times has
been the establishment of the present system of drainage, in which streams now occupy the less elevated areas between adjacent morainic ridges. The latter have been pierced in a number of places to give a more connected stream system—a feature which is well shown in the tributaries on the western side of Teer Creek (Pl. 85, Fig. 13). An incipient outlet of this type, observed at the north-west end of ridge × (Text-Fig. 3), is shown in Pl. 84, Fig. 11.
Glaciation in the Cascade, Martyr and Jackson Valleys.
Corroborative evidence of glaciation is also to be found in the valley of the Cascade River itself. Cirque remnants, often enclosing small tarns, are to be seen at a number of points along the flank of Martyr Spur, high above the gorge of the Cascade, which itself has the U-shaped profile characteristic of glaciated valleys. Again at the north-eastern end of the Hope-Blue River Range, the spurs on either side of the Colin Creek exhibit the steep faces and triangular shape characteristic of ice-shorn spurs. Finally at the base of the steep hill face on the western (inner) side of the great bend in the Cascade River, there is a large patch of bush-covered hummocky moraine with numerous undrained lakelets and ponds interspersed between the hummocks. The accumulation is not more than 100 ft. above sea-level, and was deposited as a terminal moraine just below the entrance of the Cascade Gorge just before the final retreat of the much-diminished glacier as it withdrew from the lower part of the valley. This moraine is therefore considerably younger than those already described from the Cascade Plateau.
Generalised longitudinal section down the valley of Martyr Creek. The shaded portion on the left represents the riegel cut through by the Martyr Gorge, while that on the right shows the incision by which the stream descends the glacial step, which is developed 3 ½ mls. upstream from the bridge.
During the period of maximum glaciation a large cirque was formed at the head of Martyr Creek, from which a small tributary glacier descended through a hanging valley to the main Cascade Glacier, which it joined near the point where the bridge now spans the Martyr Stream. The lip of this valley, which to-day hangs about 500 ft. to 600 ft. above the floor of the Cascade Valley, is defined by a typical riegel, developed in the gneiss which here outcrops from beneath the less resistant rocks of the Conglomerate Series. At the present time the Martyr cuts through this riegel by means of a very narrow vertical-sided canyon—the Martyr Gorge—which varies between 50 ft. and 150 ft. in depth, and extends for a distance of two miles below the bridge (Text-Figs. 1 and 4). Immediately
above the bridge, the valley of the Martyr opens out into a comparatively wide basin, the floor of which is some 50 ft. below the riegel which shuts it in. This basin has been cut partly in the somewhat easily eroded rocks of the Conglomerate Series.
Further upstream, some 3 ½ miles south of the bridge, a well developed glacial step is shown in the valley floor, just above the south-eastern boundary of the peridotite belt. A generalised longitudinal section indicating the above features is given in Text-Figure 4.
The U-shaped cross-profile of the original hanging valley of Martyr Creek, surmounting the notch of the outlet gorge, may still be plainly traced, especially when viewed from some such distant elevated point as the summit of the Cascade Plateau (Pl. 81, Fig. 3).
The long straight valley of the Jackson River appears certainly to owe its present form to glacial erosion, though the rectilinear north-easterly course of the original pre-Glacial valley was doubtless, as explained previously (Turner, 1930), determined by the major fault zone which follows along this line, across the Martyr-Jackson Divide, and up the line of the Cascade Gorge. During the period of glaciation an offshoot from the Martyr Glacier continued along this line of structural weakness, across the present divide between the Jackson and the Martyr Valleys, and down the Jackson Valley to the Arawata. This influx of ice accounts for the unusually wide floor of the present Jackson Valley. The point where the ancient glacier cut across the divide is to-day occupied by a wide low saddle only 500 ft. above sea-level, through which the track from the Jackson crosses over into the valley of Martyr Creek. On each side of the saddle almost vertical walls rise to a height of 2,000 ft. or more.
In conclusion the writer wishes to extend his sincere thanks to his companions, Professor J. A. Bartrum, and Messrs. W. E. La Roche, G. J. Williams, J. S. Thompson and G. Simpson.
The expenses incurred on the first expedition (January-February, 1929) were largely met by a Government Research Grant obtained through the New Zealand Institute, while a grant was received from the Otago University to defray part of the cost of the 1930 trip. I wish to express my appreciation of the financial help thus afforded by these two bodies.
List of Literature.
Cox, S. H., 1877. Report on Coal Measures at Jackson's Bay, Rept. Geol. Expl., 1874-1876, pp. 94-95.
Macfarlane, D., 1877. Notes on the Geology of the Jackson and Cascade Valleys, Repts. Geol. Expl., 1876, pp. 27-30.
Marwick, J., 1928. Pliocene-Pleistocene Boundary in New Zealand, Proc. 3rd Pan-Pacific Sci. Cong., 1926, vol. 2, pp. 1767-1775.
Morgan, P. G., 1928. The Definition, Classification and Nomenclature of the Quaternary Periods, ibid., p. 1776.
Turner, F. J., 1930. The Metamorphic and Ultrabasic Rocks of the Lower Cascade Valley, South Westland, Trans. N.Z. Inst., vol. 61. pp. 170-201.
New Species of New Zealand Mollusca from
[Issued separately, 29the November, 1930].
Genus Condylocardia Bernard, 1897.
Type: C. pauliana Bernard.
In reviewing the above genus Dall (1903, p. 1437) wrote—“the hinge-teeth only partially emerging from the nepionic state, so that it is difficult to decide what portion of a continuous lamina shall be called cardinal and what part lateral” and “so that when we consider the very amorphous and undeveloped condition of the laminae in Condylocardia the relationship and essential similarity of the apparently diverse hinges is tolerably plain.”
In the writer's (1930, p. 533) comparison between Condylocardia and his new genus Benthocardiella the description of the hinge characters of the former were derived from Suter's (1913, p. 910) account of that genus.
The examination of material suggests that Suter's generic description was based on the New Zealand crassicosta, for the hinge characters given do not entirely coincide with those of pauliana the genotype or concentrica the second New Zealand species.
Suter (l.c.,) stated that there were four cardinals in the right valve and two in the left, which certainly is the case in crassicosta but not in the genotype, as evidenced by Dall's (1903, p. 1437) description in which the right valve is stated to have two and the left valve three cardinals. In concentrica the total of six cardinals for the two valves coincides with the number in crassicosta but they are differently arranged, there being three in each valve.
However, this apparent diversity is merely the result of more or less rudimentary additions to an original arrangement of two strong cardinals in each valve, caused by the proximal ends of some of the cardinals becoming reflexed forming short hooked accessory cardinals.
In crassicosta the two original cardinals in the right valve are thus duplicated to four but the original two remain unchanged in the left valve, giving the formula.*
[Footnote] * The formula used in Dall's adaptation of the Steinmann System. L = left valve, R = right valve, r = resilium, the teeth are represented by units and the corresponding sockets by zeros. For any interlocking masses which cannot be classified as teeth the symbol × is employed.
0.010r010.1 = 2 cardinals + 1 lateral.
1.101r101.0 = 1 lateral + 4 cardinals.
In concentrica there is the same total of cardinals but their arrangement differs slightly. In the right valve the posterior cardinal only is duplicated while in the left valve the anterior cardinal is duplicated giving the formula.
0.010r101.1 = 3 cardinals + 1 lateral.
1.101r010.0 = 1 lateral + 3 cardinals.
Unfortunately the writer has not seen specimens or figures of C. pauliana the genotype but Dall (1903, p. 1437) gave the formula as—
1.10r101.0 = 1 lateral + 3 cardinals.
0.01r.010.1 = 2 cardinals + 1 lateral.
The essential features of the Condylocardia hinge are the reflexing of the original cardinals into accessory hooked cardinals thereby increasing the number to five or six for the two valves and also the presence of a well developed lateral in each valve.
Genus Benthocardiella Powell, 1930.
Type: B. pusilla Powell.
In the writer's description of the type species the anterior marginal tooth of the left valve was referred to as a lateral. Three additional new species have since been found and study of the hinge characters of these in conjunction with those of the genotype shows that all the teeth are better classed as cardinals and that true laterals or even alternate interlocking margins are foreign to the genus.
The only semblance of marginal interlocking is in the feeble thickening of the valve edges towards the apex of the hinge-line in the left valve. The lack of alternation in these margins, the thickened edges both being in the same valve is possibly an endeavour to preserve balance rather than a tendency towards asymmetry, for the cardinals of the left valve are more massive and weightier than those in the right valve where the thickened margins occur. Apart from this the true hinge-teeth exhibit the usual heterodont alternation.
The essential features of the Benthocardiella hinge are the presence of three or four cardinals in the left valve and two in the right and also the absence of laterals or even true alternate interlocking margins.
The typical formula can be expressed as—
010r1010 = 3 cardinals.
x01r010x = 2 cardinals.
A fourth shell of the Benthocardiella series affords an interesting example of evolution in hinge characters resulting in the formation of an additional cardinal in the left valve. This is brought about by the reflexing of the proximal end of the posterior cardinal in the left valve. This condition is seen developing as a thickened pad in orbicula
and as a distinct hook in pusilla. The formula for this species becomes—
0101r01010 = 4 cardinals.
x010rx010x = 2 cardinals.
Benthocardiella obliquata n. sp. (Figs. 4, 5 and 6).
Shell minute, thin, semitransparent, dull-white, moderately convex, equivalve; obliquely elongate-oval, anterior end greatly produced. Surface smooth. Valve margins smooth. Prodissoconch large, bounded by a raised rim and produced anteriorly and posteriorly as projecting rounded knobs. The anterior knob is not so conspicuous as the posterior, being partly immersed in the anterior dorsal margin, which latter is broadly arcuate and very slowly descending. Posterior slope steep, sinuous, truncated, falling away suddenly a short distance behind prodissoconch. Truncated portion slightly concave, subangled on joining the broadly arcuate ventral margin. Hinge typical three cardinals in the left valve and two in the right. The posterior cardinal in the left valve however lacks the hooked proximal end which feature is well developed in pusilla and hamatadens and is present as a slight thickening in orbicula. In the left valve there is first a narrow marginal space for the reception of the posterior thickened margin of the right valve, then a moderately long and narrow simple cardinal, followed by a groove which is obscured by the overhanging nature of the cardinal. This groove is for the reception of a short clasping cardinal in the right valve. After the resilium there is a short clasping cardinal, a socket, another cardinal and finally a narrow marginal space for the reception of the anterior thickened margin of the right valve. In the right valve there is first the thickened margin followed by a socket and a clasping cardinal. After the resilium there is another obscured groove for the reception of the anterior clasping cardinal of the left valve, followed by a long cardinal, then a socket and finally the anterior thickened margin.
Length, 1.06 mm.; height, 0.80 mm. (Holotype).
Length, 0.98 mm.; height, 0.74 mm.; thickness (two valves) 0.45 mm. (Paratype).
Holotype and paratype presented to Auckland Museum.
Habitat, Mangonui Heads in 6-10 fathoms (type). (Mr. W. La Roche. 1922); Tryphena Bay in 6 fathoms, Great Barrier Island (Mr. W. La Roche, 1924).
Benthocardiella orbicula n. sp. (Figs. 1, 2 and 3).
Shell minute, thin, semitransparent, dull-white, inflated, globular. Prodissoconch large, central, projecting, marked off by a rim; anterior and posterior knobs present but not prominent. Surface smooth. Valve margins smooth above but weakly crenulated ventrally by a few very feeble radial folds which are confined to the lower third of the shell. Hinge typical, three cardinals in the left valve and two in the right. In the left valve there is first a narrow marginal space for the reception of the posterior thickened margin of the right valve, then a slender cardinal thickened at the
proximal end, followed by a slight groove for the reception of the posterior cardinal in the right valve. After the resilium there is a short thickened clasping cardinal, followed by a socket, a long cardinal and finally the marginal space for the anterior thickened margin of the right valve. In the right valve there is first the slight thickening of the margin above, followed by a long socket and an equally long cardinal, then resilium, followed by an obscured groove occupied by the short clasping cardinal of the left valve; this is followed by a moderately long flexuous lamellate cardinal, then a socket and finally the slight anterior thickening of the valve edge.
Length, 0.98 mm.; height, 0.98 mm. (Holotype).
Length, 1.06 mm.; height, 1.04 mm.; thickness (two valves) 0.67 mm. (Paratype).
Holotype presented to Auckland Museum.
Habitat, Mangonui Heads in 6-10 fathoms (type). (Mr. W. La Roche, 1922); Awanui or Rangaunu Bay in 12 fathoms. (Mr. W. La Roche, 1922); 38 fathoms off Cuvier Island (Dr. H. J. Finlay); Castlecliff, Upper Pliocene (Dr. H. J. Finlay). The writer is indebted to Dr. H. J. Finlay for the opportunity for examining the Cuvier Island and Castlecliff specimens.
Benthocardiella hamatadens n. sp. (Figs. 7, 8 and 9).
Shell minute, solid, dull-white, semitransparent; moderately convex, equivalve, obliquely-ovate, anterior end produced. Surface smooth, showing faint concentric growth-lines only. Valve margins smooth. Prodissoconch large, erect, bounded by a rim and produced anteriorly and posteriorly into swollen upturned knobs. Anterior and posterior dorsal slopes steep, narrowly rounded anteriorly and broadly rounded posteriorly on reaching the convex ventral margin. Hinge-plate massive, with four cardinals in the left valve and two in the right. In the left valve there is first a narrow marginal space for the accommodation of the posterior thickened margin of the right valve, then a short strong oblique cardinal separated by an almost vertical socket from another short stout cardinal. Both cardinals are more or less connected by being fused above near the margin of the valve, the second one being a duplication caused by the reflexing of the original cardinal as explained in another part of this paper. After the resilium there is space for the reception of an obscure interlocking plate in the right valve, then a long stout cardinal bordering lower edge of hinge-plate, followed by an equally long socket, another long thin lamellate cardinal parallel to the anterior margin and finally the narrow marginal space for the accommodation of the anterior thickened margin of the right valve. In the right valve there is first a thickening of the valve edge towards the apex followed by a short oblique socket, then a large stumpy almost vertical cardinal, followed by a small almost vertical socket. After the resilium there is first an inconspicuous interlocking plate followed by a long narrow socket at lower edge of hinge-plate, followed by an equally long lamellate cardinal, then another long narrow socket and finally a slight thicken-
ing of the anterior margin. There are two subequal adductor-scars situated as in the typical species.
Length, 0.87 mm.; height, 0.91 mm. (Holotype).
Length, 0.89 mm.; height, 0.91 mm.; thickness (two valves) 0.56 mm. (Paratype).
Holotype presented to Auckland Museum.
Habitat, Mangonui Heads in 6-10 fathoms. (Mr. W. La Roche, 1922).
Genus Lodderena Iredale, 1924.
Type: Liotia minima Ten.-Woods.
Lodderena formosa n. sp. (Figs. 11 and 12).
Shell very small, almost flat above, tricarinate, widely umbilicated. Whorls 2 ¾, very rapidly increasing, including protoconch of 1 ½ smooth, almost flat whorls. Post-nuclear whorls sculptured with fine, close, spiral lirae, about twenty on the upper surface. There are three prominent spiral keels visible from the front, the upper-most bounding the almost flat upper surface, the lowest marking off the base, and the third situated at the periphery midway between the other two. On the upper surface there are two additional spiral ribs intermediate in strength, between the lirae and the keels. On the base, also, there are two of these intermediate spiral ribs, one bordering the umbilicus and the other nearer to the lowest keel. The whole shell is crossed by inconspicuous transverse sculpture which is suppressed for most of its course, being confined to strong crenulations at the sutures and edge of umbilicus and to beading on the keels and spiral ribs. Suture deeply channelled, partly bridged by the crenulations caused by the transverse sculpture. Umbilicus with a crenulated border, deep, vertical-sided, about one-quarter major diameter of base. Aperture heavily variced. Peristome as a smooth continuous inner ring. Colour dull-white (all dead shells).
Major diameter 1.4 mm.; minimum diameter 1 mm.; height 0.75 mm. (holotype).
Holotype presented to Auckland Museum, paratypes in author's collection and collection of Mr. W. La Roche.
Habitat, Mangonui Heads in 6-10 fathoms (type). (Mr. W. La Roche, 1922); 6-10 fathoms, western coast, Great Barrier Island. (Mr. W. La Roche, 1924); Maro Tiri (Chicken Island), in shellsand at low tide. (Mr. R. A. Falla, December 1923).
This species is closely allied to the genotype which differs mainly in the absence of the three strong keels.
Lodderena nana n. sp. (Figs. 13 and 14).
Shell minute, spire very little raised, tricarinate and widely umbilicated. Whorls 2 ¾ rapidly increasing, including protoconch of 1 ½ smooth slightly convex whorls. Post-nuclear whorls with three prominent spiral keels visible from the front and situated as in the preceding species. These keels are very prominent over most of the body-whorl but gradually become obsolete towards the outer lip. The whole shell is crossed by transverse sculpture which, as in the preceding species, is mostly suppressed, being confined to strong crenulations at suture and margin of umbilicus and to beading on the keels, with the exception of the latter part of the body-whorls where axial riblets continue uninterrupted right across the whorl from upper suture to umbilicus. These axials have a tendency to merge, causing fewer and stronger crenulations at the suture, which is deeply channelled as in formosa. Umbilicus with a strongly crenulated border, deep, about one-fifth
major diameter of base. Aperture circular, strengthened by a wide lamellate-varix, conspicuous from the front and below but not from above. Peristome continuous with a smooth inner rim. Colour dull-white (all dead shells).
Major diameter 0.72 mm.; minimum diameter 0.58 mm.; height 0.46 mm. (holotype).
Holotype presented to Auckland Museum, paratypes in author's collection and collection of Mr. W. La Roche.
Habitat, Mangonui Heads in 6-10 fathoms. (Dredged by Mr. W. La Roche, 1922).
This species differs from formosa in its smaller adult size, absence of the fine spiral lirae and in the presence of stronger radials, not suppressed over the latter part of body-whorl.
Genus Orbitestella Iredale, 1917.
Type: Cyclostrema bastowi Gatliff.
Orbitestella toreuma n. sp. (Figs. 16 and 17).
Shell minute, opaque, solid, discoidal, widely umbilicate. Whorls 3 biangled by two prominent spiral keels. Protoconch exceedingly small, of one smooth slightly keeled whorl. Periphery high, formed by upper keel. Lower keel of lesser diameter giving roughly, a flattened pentagonal outline to the shell, in vertical cross section. Umbilicus wide, perspective, about one-third major diameter. Spire slightly sunken. The whole shell crossed by numerous strong rounded axial costae, nodulous where they cross the spiral keels, and anastomosing towards the sutures, forming swollen nodulous sutural bands above and below. Axial costae obliquely retractive between the two keels and convexly arcuate on base. Interstices of ribs crowded with inconspicuous exceedingly fine spiral striae. Aperture subquadrate. Peristome discontinuous thin, overhanging above.. Colour pale-buff.
Major diameter 0.74 mm.; minimum diameter 0.64 mm.; height 0.27 mm. (holotype).
Habitat, Awanui or Rangaunu Bay, in 12 fathoms (Mr. W. La Roche, 1922); Mangonui in 6-10 fathoms (type) (Mr. W. La Roche, 1922).
This makes the second species of the genus to be described from New Zealand seas.
Genus Scrobs Watson, 1886.
Type. Scrobs jacksoni (Brazier) (=badia Watson).
Subgenus Nannoscrobs Finlay (1926). 1927.
Type. Amphithalamus hedleyi Suter.
Scrobs (Nannoscrobs) rugulosa n. sp. (Fig. 19).
Shell minute, solid, broadly-ovate. Whorls 3½ including low dome-shaped protoconch of 1½ convex whorls, minutely stippled
with very numerous exceedingly fine granules arranged in closely spaced linear series. Post-nuclear whorls sculptured with fine inconspicuous anastomosing spiral wrinkle-striae, slightly more prominent over base. Suture impressed, submargined by a moderately wide flat band bordered below by a faint ridge. Spire less than height of aperture. Aperture oblique-oval, much thickened and separated from the body-whorl by a broad elongated crescentic depression. Peristome continuous within. Outer lip continuing over depression and joining up body-whorl with a thickened laminated callosity. Colour dull-pink paler towards suture, base and aperture dull-white.
Height 0.98 mm.; diameter 0.69 mm. (holotype).
Holotype presented to Auckland Museum, paratypes in author's collection.
Habitat, Tryphena Bay in 5-6 fathoms, Great Barrier Island. (Dredged A. W. B. P., 1924).
This species is nearest related to S. ovata (Powell, 1927), from which it differs by being more broadly ovate with a shorter spire, more broadly submargined at suture and by the absence of basal spiral grooves and the presence of distinct but faint general post-nuclear sculpture of faint anastomosing spiral wrinkles.
Finlay's genus Nannoscrobs is here used subgenerically, as the species described above together with ovata are certainly related to hedleyi the type of the group, as shown by the style of aperture. However, another small New Zealand species, elongata Powell (1927) has an aperture more like that of Scrobs scrobiculata (Watson, 1886), while semen (Odhner, 1924) presents still another type of aperture. None of these groups are very divergent from typical Scrobs so far as shell features go, so it would seem necessary to resort to radula characters before discussing generic values.
Genus Notosetia Iredale, 1915.
Type: Barleeia neozelanica Suter.
Notosetia unicarinata n. sp. (Fig. 18).
Shell minute, solid, roughly ovate, perforate, carinated by a single strong spiral ridge. Spire a little taller than height of aperture. Whorls 4 including a large smooth protoconch of 1½ whorls, flattened on the top and somewhat oblique. Post-nuclear whorls smooth, traversed by a single strong rounded spiral ridge carinating the periphery. This is situated at about the middle on the spirewhorls. Suture impressed. Body-whorl below peripheral keel and base, evenly convex. Aperture subcircular. Peristome discontinuous but connected across parietal wall by a slight callosity. Outer lip simple, slightly thickened but not variced or internally duplicated, slightly angled above by the termination of the peripheral carina. Lower part of inner lip and basal lip evenly rounded, the former separated from the base by a small crescentic cavity. Colour dull-white.
Height 1.19 mm.; diameter 0.59 mm. (holotype).
Holotype presented to Auckland Museum, paratype in author's collection.
Habitat, Tryphena Bay in 5-6 fathoms, Great Barrier Island: (Dredged A. W. B. P., 1924).
This shell is related to simplex (Powell, 1927), which was erroneously ascribed to Lironoba by prejudice of the spiral keel. Both these shells are better placed in Notosetia on account of the simple apertures, not variced or internally duplicated. The species simplex differs from unicarinata in being more elongated and in the absence of an umbilical cavity.
Genus Rissopsis Garrett, 1873.
Type: R. typica Garrett.
Rissopsis expansa n. sp. (Figs. 20 and 21).
Shell minute, thin, semitransparent. Spire tall, almost twice height of aperture. Apex bluntly rounded. Whorls five, including visible portion of heterostrophe protoconch which is not marked off from post-nuclear whorls. The initial whorl of the protoconch is immersed by the volution of the succeeding whorl. Outlines of spire-whorls slightly convex. Body-whorl and base evenly rounded. Surface smooth and glossy. Aperture expanded, oblique, rhomoboidal, protractive below. Peristome discontinuous, slightly thickened but not variced. Outer lip convexly arcuate, protractive and projecting at a broad angle from the body-whorl, sub-angled above and broadly rounded below. Inner lip as a connecting callus across parietal whorl, resolving below into a slightly sinuous, rounded and thickened columella, free from the base and merged into the rounded basal lip. Suture impressed, strongly false-margined below by the effect of the coiling and semitransparency of the shell. Colour pale-buff.
Height 1.45 mm.; diameter 0.7 mm. (holotype).
Holotype in author's collection, paratypes in collection of Mr. W. La Roche.
Habitat, Mangonui Heads in 6-10 fathoms. (Dredged by Mr. W. La Roche, 1922).
The genotype of Rissopsis is from “Viti and Samoa Isles” and is described as being a delicately transparent shell of 10 mm. in length, having a thin sinuous and expanded peristome.
Expansa is provisionally located in Rissopsis for want of a better location.
Finlay (this volume, p. 58) has already introduced Rissopsis into the New Zealand fauna for the reception of two Tertiary species.
Genus Eulimella Jeffreys, 1847.
Eulimella larochei n. sp. (Fig. 22).
Shell small, tapering, many-whorled, thin and semitransparent. Whorls 9 including small smooth globose heterostrophe protoconch, with the initial whorl partly immersed by the next volution. The protoconch is not clearly marked off from the post-nuclear whorls.
Spire tall, over three times height of aperture. Outline of spire-whorls, body-whorl and base strongly and evenly convex. Suture impressed, distinct, very narrowly submargined. Colour transparent-whitish. Surface smooth and glossy, showing faint protractively-arcuate growth lines. Aperture vertical, subovate, sides almost parallel. Outer and basal lips simple, sharp, protractive. Columella slightly thickened, straight and vertical, merged above into a thin parietal callus.
Height 2.17 mm.; diameter 0.54 mm. (holotype).
Holotype presented to Auckland Museum, paratypes in author's collection.
Habitat, Mangonui Heads in 6-10 fathoms (type) (Mr. W. La Roche, 1922); Tryphena Bay in 5-6 fathoms, Great Barrier Island (A. W. B. P., 1924).; Awanui or Rangaunu Bay in 12 fathoms (Mr. W. La Roche, 1922).
This shell differs from the other New Zealand species in its strongly convex whorls. Judging from figures Eulimella micra Petterd and E. coacta of May not Watson, both Tasmanian species, have similar strongly convex whorls and are probably related. Also the South African E. fulgens Thiele (1925) from off Agulhas Bank in 126 metres is a similarly shaped shell.
Genus Turbonilla Risso, 1826.
Type: Turbonilla typica Dall and Bartsch
(=T. plicata Risso, 1826).
Subgenus Chemnitzia D'Orbigny, 1839.
Type: Melania campanellae Philippi.
Turbonilla (Chemnitzia) aoteana n. sp. (Fig. 15).
Shell small, subulate, opaque, white and shining. Whorls 8½, regularly increasing, including heterostrophe protoconch of 1½ globose whorls with a lateral nucleus. Outline of spire almost flat, whorls only slightly convex. Suture impressed. Post-nuclear sculpture consisting of numerous closely spaced rounded flexuous axial riblets with subequal interspaces. These are lightly chanelled, finishing abruptly just above lower suture on spire and body-whorls, and not extending over the base. The axial ribs are slightly concavely arcuate above but almost straight below, and number about 40 on the body-whorl. Suture impressed. Base rounded, smooth with the exception of a few subobsolete corrugations proceeding from the axial ribs. Aperture subvertical, elongately oval, angled above and narrowly rounded below. Peristome discontinuous, thin and sharp. Columella obliquely-arcuate, merged above into a thin parietal callosity. Colour dull-white.
Height 2.8 mm.; diameter 0.7 mm. (holotype).
Holotype presented to Auckland Museum, by Mr. W. La Roche.
Habitat, western coast, Great Barrier Island in 6-10 fathoms. (Mr. W. La Roche, 1924).
The almost flat outline of the whorls and closely spaced axials make this species quite distinctive.
Dall, W. H., 1903. Contributions to the Tertiary Fauna of Florida. Trans-Wanger Free Inst. Science Philadelphia, vol. 3, pt. 6.
Finlay, H. J. (1926), 1927. A Further Commentary on New Zealand Molluscan Systematics. Trans. N.Z. Inst. vol. 57.
Iredale, T., 1917. More Molluscan Name-changes. Proc. Malac. Soc., vol. 12, pt. 6, p. 327.
— 1924. Results from Roy Bell's Molluscan Collections. Proc. Linn. Soc., N.S.W., vol. 49.
Odhner, N. H., 1924. New Zealand Mollusca. Pap. Mort. Pacific Exped., 1914-1916, No. 19.
Powell, A. W. B., 1927. The Genetic Relationships of Australasian Rissoids. Trans. N.Z. Inst. vol. 57, pt. 1.
— 1927. Deep-water Mollusca from South-west Otago, with descriptions. of 2 New Genera and 22 New Species. Records Canterbury Museum, vol. 3, pt. 1.
— 1930. New Species of New Zealand Mollusca from shallow-water Dredgings. Trans. N.Z. Inst., vol. 60, pt. 1.
Suter, H., 1913. Manual of the New Zealand Mollusca, Government Printer, Wellington.
Tate, R. and May, W. L., 1900. Trans. Roy. Soc. South Australia, vol. 24. p. 98.
Thiele, J., 1925. Gastropoda der Deutschen Tiefsee-Expedition, Bd. 17, pl. 25, Fig. 24.
Watson, R. B., 1886. Rep. Sci. Res. Voy. H.M.S. Challenger (1873-76). Zoology, vol. 15.
New Tertiary Mollusca from New Zealand. No. 1.
[Read before the Otago Institute, 12th August, 1930; received by Editor, 15th August, 1930; issued separately, 25th November, 1930].
With the exception of two shells—Cardium strangi n. sp. and Verconella finlayi n. sp.—the Mollusca described in this paper have been recently collected by the writer. His sincere thanks are due to Dr. H. J. Finlay and to Dr. J. Marwick for assistance in identification, and also to Dr. W. N. Benson for permission to describe the very fine new species of Cardium from Chatton.
Genus Glycymeris Da Costa, 1778.
Type Arca glycymeris Linné
Glycymeris marshalli n. sp. (Figs. 13, 14).
Shell large, light of build for its size, inflated, beaks low. Outline very oblique; the line joining the apices of the chevrons (four in number) on the ligamental area correspondingly oblique. Shoulders high, little sloping. Anterior winged dorsally and descending rapidly at first, but later retreating more postero-ventrally. A fairly strong ridge running from the umbo intersects the posterior margin just below its middle forming a rounded angle. Above this the descending dorsal half of posterior margin runs posteroventrally, thereafter inclining antero-ventrally. Sculpture of numerous flat radial ribs separated by almost linear grooves, not on the posterior wing, where, however, a hand lens shows fine, closely-spaced radial striations, found also on the anterior dorsal surface, but not seen elsewhere no doubt as a result of the partially decorticated state of the shell. Teeth numerous and light, 6 to 7 fully developed on each side of ligamental area.
Height, 74 mm.; length, 69 mm.; inflation 20 mm.
Locality—Shell Gully, Chatton, near Gore, Southland (Ototaran).
Holotype and two broken paratypes in writer's collection.
The build of shell, hinge characters and sculpture show that this species has affinities with shells of the “Axinea” group, as used by Marwick (Trans. N.Z. Inst., vol. 54, p. 64; 1923).
Genus Dosinia Scopoli, 1777.
Type D. africana Hanley.
Subgenus Raina Marwick, 1927.
Type D. bensoni Marwick.
Dosinia (Raina) benereparata n. sp. (Figs. 2, 3).
Shell large, moderately inflated, slightly higher than long, drawn down postero-ventrally; beaks situated at about anterior third; dor-
sal margin well arched up. Lunule long, lanceolate, fairly well impressed; escutcheon well marked and moderately deep. Hingeplate not quite as wide and heavy as in bensoni, arched up especially behind posterior cardinal tooth. Dentition closely similar to that of the type of the subgenus but posterior cardinal somewhat more lamellar, anterior lateral higher and narrower and median cardinal perhaps not quite so unevenly divided. Sculpture of unevenly-spaced concentric ridges, crowded together closely towards ventral margin. Pallial sinus moderately deep, sharp and directed towards lower third of anterior adductor. Base of adductor scars just about at middle horizontal line of shell, whereas those of bensoni extend well below that line.
Height, 54 mm.; length, 50 mm.; thickness (one vale), 14 mm.
Locality—Shell Gully, Chatton, Southland (Ototaran).
Holotype and a broken paratype in writer's collection.
As the writer found difficulty in referring this and the following species to their subgenera he forwarded them to Dr. J. Marwick for examination. Dr. Marwick places them both in Raina, and states concerning the present shell that it is relatively higher than bensoni, the pallial sinus is directed much lower than usual in Raina and the anterior lateral tooth is high and narrow.
Dosinia (Raina) bartrumi n. sp. (Figs. 5, 7).
A large, heavily-built, inflated and orbicular shell. In dentition (left valve) and sculpture strongly reminiscent of R. nukumaruensis Marwick, but left median cardinal is wider and the lunule is not quite so impressed and is relatively longer in Dr. Marwick's species. Escutcheon well developed and deep. Pallial sinus directed towards middle of anterior adductor (thus agreeing more with nukumaruensis than with bensoni, but not so low as in the previously described species), acute and reaching about half-way across valve. At intervals of about 5 mm. one of the concentric ridges, which over the entire valve are fine and densely packed together, is more prominent than the others, standing out in somewhat more marked relief where there has been slight abrasion of the surface.
Height, 65 mm.; length, 64 mm.; thickness (one valve), 23 mm.
Locality—Kaawa Creek Beds, West Coast, South of Waikato Heads (Waitotaran).
Type (a single left valve) in writer's collection.
Of this shell Dr. Marwick writes, “Inflation greater than in any other Raina. Lunule relatively short and more impressed than usual. R. nukumaruensis is fairly well inflated and has a slightly more impressed lunule than bensoni; but has not so deep an escutcheon, a narrower left median cardinal and a large anterior lateral.”
Named in honour of Professor J. A. Bartrum, who first discovered the fossiliferous Kaawa Creek Beds, in recognition of the kindly assistance he has always been ready to give the writer over a number of years.
Genus Cardium Linné, 1758.
Type Cardium costatum Linné.
Cardium strangi n. sp. (Figs. 6, 9).
Shell large, oblique, drawn out postero-ventrally, inflated; anterior end convex, posterior end flattened; beaks at about anterior third, incurved, flattened in the plane of the hinge, directed forward. Posterior margin parallel with antero-ventral margin, produced and angled below. Ventral margin convex, ascending more in front, strongly and sharply dentate. Sculpture of about 50 broad, regular radial ribs, which tend to be somewhat flattened over most of the shell, but are more or less ridged and nodular towards basal margin; ribs separated by deep, linear grooves. On the posterior flattened area the ribs are ill-formed, the interstices wider and shallower. Growth-lines weakly defined towards ventral margin, but strongly shown undulating across the weaker ribs and grooves of the ventral part of flattened posterior area. As a result of decortication towards the beaks the radials stand out clearly, separated by flat-floored grooves whose width is sub-equal to that of the ribs. The whole are crossed by a system of fine, slightly wavy striae, about 6 to 8 per mm., those in the grooves faintly convex ventrally, those on the ridges convex dorsally. Muscular impressions strongly incised, the posterior one the larger, pedal retractor scar separate, large and elongate dorso-ventrally, hidden by hinge-plate. Hinge with two cardinal teeth, the dorsal one slightly anterior to beak and a little elongated in a direction parallel with the dorsal part of the anterior margin. The lower cardinal much larger, resembling a conical peg protruding from hinge-plate, slightly behind the beaks. Cardinals separated by a channel opening into a deep pit anterior to the lower cardinal. There are two anterior laterals, placed vertically one above the other and separated by a broad, deep pit; upper one low, elongated horizontally; lower one high, conical, pointed. Posterior lateral tooth near remote end of hinge-plate, rising abruptly from its ventral margin and with a broad pit running from above it postero-ventrally to the end of hinge-plate. Nymph broad and strong.
Height, 95 mm.; length, 105 mm.; thickness (one valve), 38 mm.
Locality—Shell Gully, Chatton, near Gore, Southland (Ototaran).
Holotype (a single right valve) in the collection of the University of Otago.
This species has affinities with C. spatiosum Hutton, and is allied to an undescribed species from Clifden, Southland, in the collections of Dr. H. J. Finlay and of the University of Otago.
Named in honour of its discoverer, Mr. D. U. Strang, of Invercargill.
Genus Elachorbis Iredale, 1915.
Type Cyclostrema tatei Angas.
Elachorbis albolapis n. sp. (Figs. 10, 11).
Shell very small, perforate, discoidal, turbinate. Protoconch of about 2½ smooth turns; whorls about 4, ornamented by strong,
sharply-elevated, regular spirals, spaced evenly, especially over the base, but interval between the third and fourth from suture of body whorl greater and almost twice that of others. Interspaces considerably wider than the ridges. Spirals visible on the coils within the wide, perspective umbilicus; about 18 on body whorl, the first two below suture weaker than the others, the ninth stronger, forming a slight angle separating the upper convex part of whorl from the slightly flattened base. Spirals seen through light callus of inner lip and within aperture; 4 on penultimate whorl. Aperture almost circular, sharp, shining within and corrugated outside by the spiral sculpture. There is a shallow infrasutural furrow bounded below by the strengthened third spiral.
Height, about 1.5 mm.; diameter, 3 mm.
Locality—White Rock River shell bed (Awamoan), South Canterbury.
Type in writer's collection (one shell).
This is the second species of Elachorbis described from White Rock River, which is the type locality for E. helicoides (Hutton). The writer recently collected E. politus (Suter) there also. Its strong, regular corrugations at once separate it from the latter species, and this feature combined with the absence of keels readily distinguishes it from Hutton's shell and from E. duplicarina Marwick from Chatton. In sculpture it approaches E. cingulatus (Bartrum) from the Pliocene beds at Kaawa Creek, and an allied undescribed species in the writer's collection from Hawkes Bay, but in these the whorls are more evenly convex and no spirals ornament the umbilicus.
Genus Modelia Gray, 1840.
Type Turbo granosus Martyn.
Modelia nukumaruensis n. sp. (Fig. 8).
Shell not large, very thick and solid for its size, imperforate, with strong spiral ornament. Sculpture consists of equally strong, well-spaced spiral lirae, the interstices of about the same width as the spirals, which bear smooth, evenly-spaced granules. The first spiral below the suture is markedly weaker than the others, and is separated from the second spiral by an interval wider than those between the others. The penultimate whorl has nine spirals (twelve in granosa). On the base the spiral ornament becomes somewhat sharper, the width of the interspaces increases to about twice that of the ridges, the granular character of which becomes less noticeable (the bases of two juvenile paratypes from Kai Iwi are entirely devoid of granules). Below the periphery of the body whorl several weak cinguli appear in the interstices emerging from beneath the callus of the inner lip, and these enlarge spirally towards the outer lip. Fine, dense growth-lines trend obliquely across the interstices and are visible also on the inter-granular saddles of the lirae (as in granosa Martyn). The early sub-nuclear whorls carry a fenestrated ornament due to low, somewhat oblique axials connecting the granules of the spirals. Protoconch (juvenile from Kai Iwi) smooth
and of about two whorls. Earliest whorls only lightly convex, but later ones become progressively more rounded; base convex. Aperture somewhat quadrate, not so oblique as in granosa Martyn. Outer lip sharp. Columella concave, oblique, iridescent.
Height, 18 mm.; diameter, 15 mm.; height of spire, 10 mm.
Locality—Pliocene beds of Kai Iwi (Castlecliffian), and Nukumaru (Nukumaruan).
Holotype (Nukumaru) and two juvenile paratypes (Kai Iwi) in writer's collection.
Readily distinguished from granosa Martyn by its smaller size, higher spire, less distended and less oblique aperture, and fewer and more regular spirals.
Finlay (Trans. N.Z. Inst., vol. 57, pp. 366-7; 1927) drew attention to the fact that no Tertiary ancestors of Modelia and Lunella were up to that time known, stating that this was certainly due to the almost total lack of quite littoral fossil deposits in New Zealand, for the ancestors of such distinct shells must certainly have lived in the same locality. In 1928, however, Professor J. A. Bartrum and the writer collected several specimens of the new species from the mid-Pliocene beds at Nukumaru and at Kai Iwi, while still more recently Powell and Bartrum (Trans. N.Z. Inst., vol. 60, p. 413; Pl. 42, Fig. 63; 1930) describe and figure a shell allied to granosa Martyn, which they collected from beds of the Waitemata Series at Oneroa, Waiheke Island, the shallow-water facies of which is shown, as these writers point out (loc. cit., p. 396), by the presence therein of such genera as Haliotis, Cellana, Bembicium, Lepsiella, Pyrazus, Bankia.
Genus Sinum Roeding, 1798.
Type Helix haliotoidea Linné.
Sinum marwicki n. sp. (Figs. 1, 4).
Shell small, greatly depressed; whorls nearly three including a smooth, planorboid protoconch of one and a-half whorls; last whorl enlarging fairly rapidly; apex excentric and nearer front edge; spire flat, about one-fifth height of shell, and dorsal surface convex; body whorl lightly excavated ventrally between inner edge of aperture and outer margin of base, the concavity becoming more marked towards the small, partly hidden umbilicus. The upper surface has slightly undulating, somewhat flattened spiral threads, about 35 in number (3 per mm.), separated by grooves slightly wider than the ridges. Towards the periphery the last ten or so lirae suddenly become finer and the width of the interstices less in relation to that of the ridges. These are crossed by well-defined convex growth-lines. No spirals are developed on the base, but the lines of growth are prominent as they sweep convergingly into the umbilical tract. Suture markedly tangential. Aperture large, circular, nearly two-thirds greatest diameter of shell, angled above. Outer lip thin and strongly convex; inner lip covering parietal wall (callus partially broken away in specimen), reflexed and partly hiding umbilicus.
Height, 5 mm.; greatest diameter, 14 mm.; least, 11 mm.
Locality—White Rock River shell bed (Awamoan), South Canterbury.
Holotype (the only specimen) in the writer's collection.
This is the third species of Sinum s. str. described from the Tertiary of New Zealand. It is not unlike S. infirmum Marwick from the Awamoan beds of Ardgowan and Pukeuri, but is readily separable on account of its less excentric apex and more compressed character, causing a sharper periphery to the body whorl, which also enlarges less rapidly in the new species than it does in S. infirmum.*
Genus Verconella Iredale, 1914.
Type Fusus dilatatus Q. and G.
Verconella finlayi n. sp. (Figs. 12, 15).
Closely allied and probably ancestral to V. marwicki Finlay (Trans. N.Z. Inst., vol. 61, p. 67; Pl. 2, Figs. 15 and 16), which it resembles in detail of sculpture and general build of shell, but it differs at sight in its less slender and less graceful outline. Spire relatively shorter than that of marwicki, but wider at base, so that it rises less steeply; spire 2½ times height of aperture plus canal, whereas in marwicki it is slightly over twice the height of aperture plus canal. Tubercles, especially those on body whorl, placed less than their own width apart, 10 on penultimate and 11 on body whorl. Periphery even lower than in marwicki, the suture undulating over the tubercles and on the penultimate whorl almost covering them. Shoulder of body whorl a good deal more excavated than that of the Mt. Harris shell.
The following are measurements taken in comparing shells of the same length, the specimen of V. marwicki being a topotype (Mt. Harris):
|Length||98 mm.||98 mm.|
|Height of spire||33 mm.||31 mm.|
|Width of body whorl||55 mm.||60 mm.|
|Length of suture of body whorl||95 mm.||109 mm.|
|Angle of spire||68°||80°|
Locality—Blue Cliffs, South Canterbury, sandy clays above limestone (Hutchinsonian). Collected by Dr. P. Marshall.
Holotype (unique) in writer's collection.
Separable at sight from V. marwicki by the relatively greater width of the last whorl, with its more excavated shoulder, greater angle of spire and lower periphery to whorls.
[Footnote] * Since the above was written the writer has collected a perfectly preserved topotype of S. infirmum Marwick, its dimensions being slightly less than those given for the holotype.
This is another species of the marwicki-adusta line, discussed by Finlay (Trans. N.Z. Inst., vol. 61, pp. 67-70). In its very low periphery and almost straight spire whorls the new species resembles a specimen (in the writer's collection) of V. affixa Finlay from Clifden, band 6 B. The differences in sculpture, however, between marwicki and affixa, noted by Finlay (loc. cit., p. 69), exist also between the latter species and that described above.
The writer has pleasure in associating this shell with Dr. H. J. Finlay, who has given him a great deal of assistance and advice in molluscan matters generally.
Literature Referred To.
Bartrum, J. A., 1919. New Fossil Mollusca, Trans. N.Z., Inst., vol. 51, pp. 96-100.
Finlay, H. J., 1924. Additions to the Recent Molluscan Fauna of New Zealand, Trans. N.Z. Inst., vol. 55, pp. 517-526.
— 1926. A Further Commentary on New Zealand Molluscan Systematics, Trans. N.Z. Inst., vol. 57, 1927, pp. 320-485.
— 1930. New Shells from New Zealand Tertiary Beds; Part 3, Trans. N.Z. Inst., vol. 61, pp. 49-84.
Marwick, J., 1923. The Genus Glycymeris in the Tertiary of New Zealand, Trans. N.Z. Inst., vol. 54, pp. 63-80.
— 1924. The Tertiary and Recent Naticidae and Naricidae of New Zealand, Trans. N.Z. Inst., vol. 55, pp. 545-579.
— 1927. The Veneridae of New Zealand, Trans. N.Z. Inst., vol. 57, pp. 567-635.
— 1929. Tertiary Molluscan Fauna of Chatton, Southland, Trans. N.Z. Inst., vol. 59, pp. 903-934.
Powell, A. W. B., and Bartrum, J. A., 1929. Mollusca from Kaawa Creek Beds, West Coast, South of Waikato River, Trans. N.Z. Inst., vol. 59, pp. 139-162.
— 1930. The Tertiary (Waitematan) Molluscan Fauna of Oneroa, Waiheke Island, Trans. N.Z. Inst., vol. 60, pp. 395-447.
Suter, H., 1913. Manual of the New Zealand Mollusca, Government Printer, Wellington.
— 1914. Revision of the Tertiary Mollusca of New Zealand, Pt. 1, N.Z. Geol. Surv. Pal. Bull. No. 2.
— 1917. Descriptions of New Tertiary Mollusca occurring in New Zealand, N.Z. Geol. Surv. Pal. Bull. No. 5.
List of Lepidoptera of Whangarei.
[Read before the Wellington Philosophical Society, 28th May, 1930; issued separately, 29th November, 1930].
I wish to place on record my thanks and indebtedness to G. V. Hudson, Esq., F.E.S., F.N.Z. Inst. It was entirely due to his kindly encouragement that I commenced these investigations and to his constant help in every way, more especially in identifying specimens for me, and to his beautiful book, that I have been able to carry them out.
The district worked was Paranui Hill, about 3 miles East of Whangarei Post Office. The house is upon the extreme South corner of a plateau. To the East is a considerable gully clothed in heavy bush (a scenic reserve) having a stream running through the bottom, and reaching to within a few yards of the house. Beyond this gully is a large area of gumfield covered with stunted scrub rising to about 800 feet. Only the extreme edge of this gumfield, adjacent to the gully, has been worked.
To the South-west is also a considerable area of bush, below which is scrub and a few small swamps eventually dropping down to the river about 150 feet below. To the West and North are orchards surrounded and divided by shelter belts of Pinus insignis, Cupressus macrocarpa and native trees and shrubs. Beyond the orchards are pastures with patches of scrub in places. All insects mentioned in this list have been taken within a half-mile radius of the house, except where otherwise stated.
In these notes L means attracted by light.
B means beaten out of bush during the daytime.
S means beaten out of scrub, shelter belts, edge of bush, etc., at dusk.
T means taken from tree trunks.
F means attracted by blossoms chiefly Buddlea of which there is a large bush near the house.
|Danaida plexippus||One seen in orchard, 1923. Two reported in Whangarei district, 1928-29.|
|Dodonidia helmsi||Two seen in orchard, February, 1926. Several February, 1929. Several February, 1930.|
|Vanessa gonerilla||Occasionally in orchard.|
|V. itea||One seen February, 1929.|
|V. cardui||Several on hilltops at Kara, eight miles West of Whangarei.|
|Chrysophanes salustius||Rather frequent in November and December, but never numerous.|
|Lycaena labradus||Abundant from October throughout.|
|Nyctemera annulata||Common throughout the entire year.|
|Heliothis armigera||Numerous on F in January and February.|
|Graphiphora compta||Several, F.|
|Aletia unipuncta||Not uncommon, L.|
|Persectania steropastis||Occasionally, L.|
|P. composita||Rather common, L.|
|P. atristriga||At times rather numerous, L.|
|Erana graminosa||Rather numerous throughout the season, L. and T.|
|Melanchra insignis||Rather common, L.|
|M. plena||Rather common, L and T.|
|M. mutans||Rather common, L.|
|M. ustistriga||Occasionally, L and F.|
|M. lignana||Rather common, L.|
|M. ochthistis||Occasionally, L and F.|
|Bityla defigurata||Occasionally, L.|
|Ariathisa comma||At times numerous, L.|
|Hypenodes costistrigalis||Rather numerous during August and September, S. Occasionally, throughout season, L.|
|H. anticlina||Taken November, B.|
|Catada lignicolaria||Occasionally, L.|
|Plusia chalcites||Occasionally, L, numerous, F. Common.|
|P. oxygramma||Not uncommon, F, February and March.|
|Dasypodia selanophora||Occasionally, L.|
|Rhapsa scotosialis||Very numerous.|
|Sphinx convolvuli||One taken in a garden in Whangarei, March. The larva is fairly often found on kumara plants in the district.|
|Tatosoma lestevata||Taken October, L.|
|T. tipulata||Not uncommon in December and January in house and T.|
|T. timora||Occasionally throughout the year, L. Not uncommon.|
|T. topia||Rather numerous August and September, L. Occasionally in January and February.|
|Microdes epicryptis||Several August and September. Occasionally November and December, L.|
|Phrissogonus laticostatus||Rather numerous, L and B and S.|
|P. testutalus||Occasionally, B.|
|Chloroclystis semialbata||Rather numerous, L, S.|
|C. plinthina||Several July, August, September, L.|
|C. paralodes||Rather numerous July, August, September, L. Occasionally January and February.|
|Eucymatoge gobiata||Occasionally from August throughout the season, L and B and S.|
|E. anguligera||Occasionally from September throughout the season, B.|
|Hydriomena rixata||Rather numerous during November, B.|
|H. similata||Frequent throughout the year, L, B and S and T.|
|H. callichlora||Occasionally, L, B and T.|
|H. deltoidata||Rather numerous February, S.|
|H. subochraria||Occasionally, L and S.|
|Asthena pulchraria||Abundant throughout the year, L, B, S.|
|A. subpurpureata||Abundant July, August, September. Occasionally throughout.|
|Euchoeca rubropunctaria||Very numerous throughout.|
|Venusia verriculata||Numerous August and September. Several January and February, L, B.|
|V. undosata||Taken August, L.|
|Orthoclydon praefeetata||Occasionally October and December, L, S.|
|Asaphodes megaspilata||Numerous throughout, L, B and S.|
|Xanthorhoe rosearia||Odd examples during the winter. Rather numerous August and September, L, B, S.|
|X. lucidata (practica)||Rather numerous throughout winter and spring, L, S.|
|X. venipunctata||Taken October, L.|
|X. cinerearia||Numerous throughout.|
|X. semisignata||Rather numerous throughout.|
|Adeixis griseata||Taken in September and October. Rather numerous November and December, S, edge of gumfield.|
|Epirrhanthis ustaria||Rather numerous throughout, L.|
|Selidosema pelurgata||Occasionally, B.|
|S. aristarcha||Occasionally, L. Numerous throughout, B and S.|
|S. productata||Very numerous, L, B, T.|
|S. indistincta||Occasionally, L and B.|
|S. leucelaea||Frequent January and February, L, B, T.|
|S. suavis||Very numerous, L, B, S.|
|S. rudiata||Occasionally, S.|
|S. fenerata||Very numerous during winter and spring. Frequent throughout.|
|S. adusta||December, B.|
|S. panagrata||Frequent, L, B.|
|S. dejectaria||Frequent, L, B.|
|Sestra flexata||Numerous November, December, B. Occasionally, L.|
|Gargaphia muriferata||Rather numerous throughout, L, B.|
|Azelina variabilis||Taken September and occasionally throughout, S.|
|A. gallaria||Taken September, B.|
|A. nelsonaria||Taken February, F.|
|Declana leptomera||Rather numerous during the winter, and occasionally throughout.|
|D. floccosa||Numerous November and December, L, T.|
|D. feredayi||Occasionally, L.|
|D. junctilinea||Occasionally, L.|
|Crambus ramosellus||Numerous, L, S.|
|C. simplex||Rather numerous, L, S.|
|C. siriellus||Rather numerous December and January, S, on edge of gumfield.|
|C. apicellus||Rather numerous, L, S.|
|C. vittellus||Numerous, L, S.|
|C. flexuosellus||Numerous, L, S.|
|Diptychophora pyrsophanes||Several November, B.|
|D. chrysochyta||Rather numerous November and December, S.|
|D. interrupta||Several January, B.|
|D. lepidella||Rather numerous December and January, S, B, L.|
|D. leucoxantha||Taken October, B.|
|D. selenaea||Rather numerous January and February, B, L.|
|D. auriscriptella||Numerous November, December and January, S, B, L.|
|D. elaina||Numerous throughout season, L, S, B.|
|D. parorma||Not uncommon, S, L.|
|Gadira acerella||Taken January, L.|
|Nymphula nitens||Taken February, L.|
|Musotima aduncalis||Several throughout the season, L, B. Not uncommon.|
|M. nitidalis||Rather numerous, L, S, B.|
|Proternia philocapna||Numerous December, January and February, L. Occasionally, S.|
|Nesarcha hybrealis||Several September, L. January, B.|
|Mecyna maorialis||Rather numerous, F, February.|
|M. daiclealis||Several October, L. February, F and B. Not uncommon.|
|M. flavidalis||Rather numerous throughout.|
|Scoparia philerga||Numerous during the spring, B, S, L.|
|S. meliturga||Not numerous. Fairly common during the winter.|
|S. minusculalis||Taken October.|
|S. chimeria||Numerous, B, S, L, November, December, January.|
|S. dinodes||Numerous, T, also B and L, February, March.|
|S. acharis||Taken October, B.|
|S. ustimacula||Fairly common during winter and early spring. Several January.|
|S. periphanes||Several October, S and L.|
|S. colpota||Fairly frequent February, March, L and T.|
|S. submarginalis||Rather numerous January and February, L and S.|
|S. indistinctalis||Rather numerous January and February, L and S.|
|S. bisinualis||Rather numerous throughout the year, L, B, S.|
|S. chalicodes||Several March, April, L.|
|S. leptalea||Taken July, L.|
|S. epicomia||Taken October, B.|
|S. feredayi||Rather numerous November, December, January, B, S, L.|
|S. steropaea||Numerous October to March, B, S, L.|
|S. elaphra||Taken January, B.|
|S. sabulosella||Abundant October and November, S.|
|S. trivirgata||Single taken November and January, S.|
|S. aspidota||Several November, L.|
|S. luminatrix||Taken November, B.|
|S. octophora||Very numerous November, December and January, S.|
|Diplopseustis perieralis||Odd specimen throughout the winter. Rather numerous August, September, November, December, L, S, B.|
|Pyralis farinalis||Taken January. Fence.|
|Catamacta rureana||Taken November, B.|
|C. gavisana||Occasionally, B, S.|
|Capua plagiatana||Occasionally, S.|
|C. plinthoglypta||Taken November, S.|
|C. semiferana||Rather numerous, S.|
|C. intractana||Several, L.|
|Tortrix indigestana||Numerous, S, edge of gumfield, December.|
|T. postvittana||Occasionally, B.|
|T. orthocopa||Four specimens taken January, S.|
|T. conditana||Occasionally S.|
|T. alopecana||Several taken December, January, S.|
|T. excessana||Rather numerous, S, L.|
|T. flavescens||Several January, S, L.|
|T. scruposa||Rather numerous November and December, S, edge of gumfield.|
|T. torogramma||Frequent January and February, S.|
|Epalxiphora axenana||Rather numerous, S, T.|
|Cnephasia incessana||Rather numerous November, B, occasionally throughout.|
|C. jactatana||Frequent throughout, L, B, S.|
|Spilonota dolopaea||Taken September.|
|S. parthenia||Rather numerous October, S.|
|S. zopherana||Very numerous, S.|
|S. ejectana||Very numerous, S.|
|S. macropetana||Several December, January, S.|
|Eucosma querula||Several, S.|
|Bactra noteraula||Rather numerous January, February, L.|
|Laspeyresia pomonella||Occasionally, L. Larva very numerous.|
|Megacraspedus calamogona||Single taken October and January.|
|Aristotelia paradesma||Two taken January, L.|
|Phthorimaea melanoplintha||Taken March, L.|
|P. operculella||Several March, April, L.|
|Endrosis lacteella||Frequent in house.|
|Borkhausenia armigerella||Rather numerous October, November, S.|
|B. basella||Very numerous October, November, B.|
|B. chloradelpha||Rather numerous, October, S.|
|B. ancogramma||Rather numerous November, December, January, S and B.|
|B. innotella||Rather numerous November, December, S.|
|B. plagiatella||October, S.|
|B. pseudospretella||At times in house.|
|Leptocroca scholaea||Very numerous December, January, S, B.|
|Compsistis bifaciella||Occasionally clearings, B, November, December, January.|
|Gymnobathra hyetodes||Rather numerous January, February, S. Occasionally, B.|
|G. flavidella||Numerous December, January, February, B, occasionally, L.|
|G. parca||Occasionally November, December, S.|
|G. calliploca||Several January, February, B.|
|G. bryaula||Fairly numerous January, February, T. ♀ Much more numerous than ♂.|
|G. tholodella Izatha peroneanella||Fairly numerous December, January, February, L, T, B.|
|I. picarella||Taken November, L.|
|I. epiphanes||Rather numerous November, December, L. S, B.|
|I. parasophyta||Occasionally December, January, B, T.|
|I. balanophora||Several January, S.|
|Trachypepla euryleucota||Several February, L, F.|
|T. amphileuca||Two taken November, S.|
|T. hieropis||Taken November, S.|
|T. galaxias||Several October, November, S.|
|T. contritella||Taken November, S.|
|T. aspidephora||Several January, February, B, T.|
|T. indolescens||Several February, L.|
|T. eumenopa||Taken November, B.|
|Euprionocera notabilis||Single specimens taken August and February, L.|
|Barea dinocosma||Rather numerous October, November, B.|
|B. confusella||Frequent December, January, L, S.|
|Cryptolechia liochroa||Several November, B.|
|C. rhodobapta||Several November, B.|
|Phycomorpha metachrysa||Taken December, B.|
|Isonomeutis restincta||Several November, December, January, B.|
|Carposina adreptella||Taken October, B.|
|C. charaxias||Several taken December, January and February, S, B.|
|C. eriphylla||Several June, L.|
|C. gonosemana||February, T.|
|C. iophaea||Taken March, B.|
|Vanicela disjunctella||Occasionally in spring, L. Rather numerous January, February, B.|
|Stathmopoda caminora||Rather numerous October to March, B, L.|
|S. phlegyra||Rather numerous October to January, B.|
|S. skelloni||Rather numerous October to January, B, L.|
|S. mysteriastis||Taken February, L.|
|Pyroderces apparitella||Rather frequent November, December, January, L. Occasionally, B.|
|Thectophila acmotypa?||Taken March, B.|
|Batrachedra eucola||Taken February, S.|
|Heliostibes atychioides||Taken December, B.|
|Simaethis combinatana||Taken January, B.|
|Choreutis bjerkandrella||Occasionally, L, once, B. December, January and February.|
|Glyphipteryx transversella||Taken December, B.|
|G. iocheaera||Taken December, B.|
|G. leptosema||Taken November, B.|
|G. zelota||Occasionally December, January, B.|
|Elachista gerasmia||Several November, December, January, S.|
|Parectopa citharoda||Taken November, B.|
|Gracilaria linearis||Numerous November, December, January, S, B.|
|G. chrysitis||Occasionally November, December. Rather numerous January, February, B.|
|G. chalcodelta||Taken March, B.|
|Cadmogenes literata||Frequent December, January, B.|
|Orthenches glypharcha||Taken October, B.|
|Plutella sera||Rather frequent August, September, L.|
|P. maculipennis||Rather numerous January, February, March, L, S.|
|Opogona omoscopa||Numerous throughout the year, L.|
|Eugennaea laquearia||Taken, December, B.|
|Erechthias terminella||Rather frequent September, L. Occasionally January, February, B.|
|E. exospila||Several January, February, B.|
|E. hemiclistra||Occasionally November, December, January, B.|
|Hectacma chionodira||Rather frequent September to February, B, L.|
|Endophthora omogramma||Several February, B, T.|
|E. pallacopis||Taken March, T.|
|Crypsitricha pharotoma||Occasionally October, L. February, T.|
|C. mesotypa||Rather frequent January, February, T, B|
|C. roseata||Taken September, L.|
|Archyala paraglypta||Several March, L.|
|Sagephora felix||Several February, T, B.|
|S. phortegella||Rather frequent December, January, February, B, S.|
|Monopis ethelella||Numerous throughout the year, L, S.|
|Prothinodes grammocosma||Frequent September, October, B, Occasionally January, February.|
|Trithamnora certella||Rather numerous November, December, B.|
|Lysiphragma epixyla||Taken March, T.|
|Lindera tessellatella||Taken January.|
|Mallobathra homalopa||Taken November, B.|
|Coleophora spissicornis||Rather numerous November, December, S, L.|
|Hepialus virescens||Occasionally in house.|
|Porina enysii||Several January, February, L.|
|P. signata||Taken October, L.|