Molluscan Fauna of the Waiarekan Stage of the Oamaru Series.
[Read, by permission of the Director of the N.Z. Geological Survey, before the Wellington Philosophical Society, 8th October, 1924; received by Editor, 22nd December, 1924; issued separately, 13th March, 1926.]
In the winter of 1921 the writer was enabled to make a collection of marine fossils from the Waiarekan tuffs between Lorne (formerly Whitstone) and Enfield, north Otago. The exact spot had been accurately described in a letter to Mr. P. G. Morgan by Mr. Thomas Esdaile, formerly a resident of the district, but now of Kalgoorlie. The fauna proved to be so obviously different from the one usually considered as typical of the Waiarekan stage that it led to a critical examination of the Esdaile collections in the possession of the Geological Survey. The results were startling. The shells from locality 630 were found to be, in all probability, from the Waihao green-sand at McCullough's Bridge (Marwick, 1924, p. 280), and had been wrongly attributed to Mr. Esdaile; those from locality 831, the true Esdaile collection, can be divided into at least four groups, each with a distinct matrix and fauna. Further, most of the identifications made by Suter (1921, p. 79) are quite wrong.
Fig. 1.—Diagrammatic sketch of area from Lorne westward to railway-crossing. Ototaran limestone at top of escarpment, Waiarekan tuffs below.
(Scale: About 1 in. to 6 chains.)
Therefore, to give the Waiarekan stage a definite palaeontological basis, it is here proposed that the hillside immediately west of Lorne be taken as the type locality. This will probably result in the limiting of the Waiarekan stage to the period represented by the tuffs, a proceeding already suggested by the author of the stage (Thomson, 1916, p. 35).
The collection was gathered from two spots—(A) the top of a tilted ledge outcropping from the grass-covered talus about 50 ft. above the level of the railway and several chains north of it, between a quarter and half a mile west of Lorne Railway-station; (B) in a small niche in the face of the hill some 200 yards farther east and about 100 ft. below the summit of the limestone-crowned escarpment.
The fossils occur in a thin band of volcanic conglomerate, the pebbles of which are up to 3 in. in diameter, some completely rounded, but others with only the sharp edges smoothed off. These are set in a characteristic green matrix consisting of calcareous, pebbly, tuffaceous clay, crowded with Foraminifera. The outcrop at A is identical in appearance with that at B, and from its occurrence is probably part of a large fallen block.
In addition to the mollusca described below, several brachiopods and a small echinoderm were obtained. The former are in the hands of Dr. J. A. Thomson, and the latter has been sent to Dr. H. L. Hawkins, of Reading.
Revision of Suter's List from Loc. 831, Cave Valley and Upper Waiareka Valley (1921, p. 79).
This collection is a heterogeneous one; but the specimens from the type locality are easily distinguishable by the peculiar light-green colouring of their matrix. In the following lists Suter's identifications are given first, the serial numbers indicating their position on his list.
Lorne. Matrix of green foraminiferal calcareous clay:—
Whitish calcareous matrix, sometimes richly foraminiferal, sometimes with considerable tufaceous matter (perhaps from more than one locality):—
Coarse whitish-brown sandstone (? locality):—
Dark-brown rusty sandstone, probably from vicinity of Windsor or Tapui:—
Cardium patulum? = Cardium sp. with about 40 ribs on the front and middle of the disc; the ribs do not show plainly on the posterior. C. patulum has well over 100 ribs, and is probably a Protocardia (Nemocardium).
Cylichnella enysi = Bulinella n. sp. Casts not so cylindrical as enysi.
Cytherea sp. ? = Eucrassatella sp. of quite characteristic shape.
Panope orbita = Panope worthingtoni. Longer and more regular than P. orbita.
Psammobia lineolata = a cast showing part of hinge of an equilateral shell with long well-developed laterals; probably Mactra.
Struthiolaria minor = Monalaria concinna (juvenile).
Struthiolaria tuberculata concinna = Monalaria concinna.
Tellina eugonia? = Tellina n. sp. 25 mm. by 16 mm. Beaks only 11 mm. from posterior end; posterior dorsal margin well curved.
33. Turritella concava = Turritella n. sp. The specimen is identical in preservation and other features with a common unnamed shell in the greensands at McCullough's Bridge, Waihao. It is almost certain that the specimen came from there and was accidentally included with the Waiarekan collection. It bears the label “Turritella pagoda” in Suter's writing. The change was probably made because the neanic shell of T. concava has a strong spiral keel. It is nevertheless easily distinguished from T. pagoda. The specimen we are dealing with does not belong to either species.
Since localities (c) and (d) contain Monalaria concinna, which indicates a Bortonian age, they probably are from the marine sands overlying the Ngaparan coal-measures.
|Fossularca januaria n. sp.||Turritella tophina n. sp.|
|Glycymeris lornensis Marwick||Sigapatella vertex n. sp.|
|Chlamys enfieldensis n. sp.||Uber esdailei Marwick|
|Mantellum inconspicuum n. sp.||Trivia pinguior n. sp.|
|Limatula trulla n. sp.||Erato vulcania n. sp.|
|Ostrea n. sp. cf. mackayi Suter||Austrotriton n. sp.|
|Eucrassatella media n. sp.||Fusinus n. sp.|
|Diplodonta infrequens n. sp.||Mitra n. sp. cf. inconspicua Hutton|
|Kellia antiqua n. sp.||Vexillum lornense n. sp.|
|Nemocardium semitectum n. sp.||Semitriton revolutum (Finlay).|
|Venericardia benhami (Thomson)||Clavatula humerosa n. sp.|
|Serpulorbis lornensis n. sp.||Turricula esdailei n. sp.|
|Siliquaria senex n. sp.||Lornia limata n. sp.|
|Turritella lornensis n. sp.|
It will be seen that practically all of the species are new, and that no Recent ones are represented. The former result will not be surprising to those who have made a careful comparison of any of the earlier Tertiary faunas with Suter's lists of the same. Some of the alterations made are, of course, due to a more strict interpretation of certain species; but a glance at the revised list of locality 831 will show that in most cases the “personal factor” cannot be cited in explanation. The position must be faced that a great number of Suter's identifications are unreliable, especially those dealing with extinct species. This is all the more difficult to understand when one considers the excellence of his great book; the Manual of the New Zealand Mollusca, and can be ascribed only to the pressure of accumulated material causing hasty work.
The absence of Recent species in the collection indicates considerable antiquity; and, although we cannot yet tell the exact position of the Waiarekan on the European time-scale, it seems fair to conclude that it is Oligocene or late Eocene.
The types of all new species described below are now in the Geological Survey collection.
Fossularca januaria n. sp. (Plate 72, figs. 1, 5.)
Shell small, oval, strong, much inflated. Beaks strong, high, at anterior two-fifths. Sculpture of sharp concentric ridges, about 7 per
millimetre, with microscopic radials in interspaces; marginal half of disc with, in addition, strong concentric growth-ridges. Hinge with about 10 anterior and 14 posterior teeth, with a considerable median space. Cardinal area somewhat short, fairly broad, with a triangular ligamental pit bearing vertical striae.
Height, 10 mm.; length, 13 mm.; thickness of one valve, 5.5 mm.
Locality 831; Esdaile collection.
Additional material has shown that the left valve differs from the right in having strong radial sculpture, also that the single ligamental groove shown in the figure of the type is only the anterior side of a shallow triangular striated pit.
Chlamys enfieldensis n. sp. (Plate 72, fig. 11.)
Shell of moderate size, inequilateral. Ears unequal. Sculpture: right valve with about 26 or 28 strong flattened radial ribs with wider interstices, finer on anterior part of disc, at about 20 mm. from apex a fine secondary rib appears in each interspace, concentric growth-lines cause scales on ribs, generally more apparent on interstitial riblet; posterior ear with 6 narrow radial ribs of different strengths; anterior with 3; left valve with about 40 rounded scaly ribs alternating in strength and appearing at successive stages in development of shell.
Height, 50 mm.; length, 50 mm.; thickness of one valve, 9 mm.
Belongs to the C. hutchinsoni group, but differs from that species in smaller size and fewer ribs. The only fairly complete left valve is as strongly inflated as the right, but this may be exceptional.
Mantellum inconspicuum n. sp. (Plate 72, fig. 4.)
Shell very small, thin, obliquely oval, inflated. Beaks broad, at anterior third. Ears moderate. Sculpture of about 40 sharp radials with broad rounded interstices. Hinge-margin long, one-half total length of shell. Ligament-pit broad.
Height, 4.5 mm.; length, 4.5 mm.; thickness of one valve, 1.5 mm.
Distinguished from L. angulata Sowb. by its small size, greater compactness, longer hinge-line, and more regular ribbing.
Limatula trulla n. sp. (Plate 72, figs. 2, 3.)
Shell small, high, well inflated, with very small ears. Sculpture on centre of disc of about 18 sharp radial ribs with wide rounded interstices; anterior and posterior areas without radials; whole surface with well-defined regular growth-lines causing denticles where they cross ribs. Hinge-area relatively broad, upper margins sloping well down, lower margin only slightly curved. Ligament-pit wide.
Height, 13 mm.; length, 7 mm.; thickness of one valve, 3 mm.
Easily distinguished from L. bullata Born by the smaller ears, more sloping dorsal margins, straighter sides, and small size.
Eucrassatella media n. sp. (Plate 72, fig. 6.)
Shell rather small, moderately inflated. Beaks high and strong, at anterior fourth. Anterior end narrowly rounded; posterior very broadly truncated. Lunule and escutcheon deeply sunken. Surface with regular concentric ribs separated by narrow interstices, about 16 per centimetre; sculpture developed only on centre of disc, anterior and posterior areas being smooth. Hinge of right valve with anterior cardinal very
weak, amalgamated with lunular margin for top half of length, median cardinal strong, posterior cardinal extremely weak, scarcely separated from median.
Height, 16.5 mm.; length, 20 mm.; thickness of one valve, 5.5 mm.
This species is easily distinguished from E. trailli (Hutton) by the strong forward-tilted beaks, sculpture confined to centre of disc, and by details of hinge.
Diplodonta infrequens n. sp. (Plate 72, fig. 9.)
Shell small, subquadrate, moderately inflated, winged posteriorly. Beakå low, at anterior fourth. Anterior end narrowly rounded; dorsal margin almost straight, slightly ascending; posterior margin straightened above, broadly rounded below. Sculpture of extremely fine regular close concentric threads, about 10 per millimetre, with a few indistinctly marked rest-periods. Left hinge with 2 cardinal teeth, anterior one thick and bifid, posterior narrow and entire.
Height, 10 mm.; length, 11 mm.; thickness of one valve, 3 mm.
Distinguished from D. zelandica by the much narrower anterior end and broad posterior; from the other New Zealand species by its smaller inflation.
Kellia antiqua n. sp. (Plate 72, fig. 7.)
Shell rather small, inflated, suboval. Beaks at anterior fourth. Anterior margin convex, straightened above; posterior dorsal margin almost horizontal; posterior margin straightened above, narrowly convex below; ventral margin somewhat straightened. Surface smooth with a few scattered growth-lines.
Holotype in collection of New Zealand Geological Survey.
Height, 5 mm.; length, 6.5 mm.; thickness of one valve, 1.75 mm.
The generic position is not certain, because the type and only specimen is a closed individual. One of the umbos was removed and an attempt made to explore the hinge, but without success. The shell is not a Diplodonta, for no ligamental nymphs can be seen. Kellia has an obsolete external ligament, so that the dorsal margin is not excavated; it is therefore probable that this is the correct generic location.
Nemocardium semitectum n. sp. (Plate 72, fig. 8.)
Shell rather small, subquadrate, inflated. Beaks central, prominent. Surface with 6 radial ribs per millimetre with linear interstices at 22 mm. diameter on anterior and middle of disc. Hinge weak; right valve with at least 1 conical cardinal and apparently single anterior and posterior laterals, but not well enough preserved to show clearly.
Height, 13.5 mm.; length, 13.5 mm.; thickness of one valve, 6 mm.
This is the P. pulchella of Suter (1921, p. 79). N. semitecta differs from that species in having twice as many ribs, and linear (not wide) interstices; also, the shape is more quadrate, being not so oblique posteriorly; the hinge is weaker, and the shell more inflated.
Serpulorbis lornensis n. sp. (Plate 72, fig. 10.)
Shell tubular, all that remains being closely knotted, but there was probably a projecting free tube. Sculpture of spiral cords with wider
Figs. 1, 5.—Fossularca januaria n. sp.: holotype. × 2.
Fig. 2.—Limatula trulla n. sp.: holotype. × 1–½.
Fig. 3.—Limatula trulla n. sp.: paratype. × 3.
Fig. 4.—Mantellum inconspicuum n. sp.: holotype. × 3.
Fig. 6.—Eucrassatella media n. sp.: holotype. × 1.
Fig. 7.—Kellia antiqua n. sp.: holotype. × 2–½.
Fig. 8.—Nemocardium semitectum n. sp.: holotype. × 1–½.
Fig. 9.—Diplodonta infrequens n. sp.: holotype. × 2.
Fig. 10.—Serpulorbis lornensis n. sp.: holotype. × 1.
Fig. 11.—Chlamys enfieldensis n. sp.: holotype. × 1.
Fig. 12.—Siliquaria senex n. sp.: holotype. × 1–½.
Fig. 13.—Vexillum lornense n. sp.: holotype. × 3.
Figs. 14, 15.—Trivia pinguior n. sp.: holotype. × 3.
Fig. 16.—Sigapatella vertex n. sp.: holotype. × 2.
Fig. 17.—Sigapatella vertex n. sp: paratype. × 2.
Fig. 18.—Turricula esdailei n. sp.: holotype. × 2.
Fig. 19.—Clavatula humerosa n. sp.: holotype. × 1–½.
Fig. 20.—Turritella lornensis n. sp.: holotype. × 1.
Fig. 21.—Turritella tophina n. sp.: holotype. × 1.
Fig. 22.—Semitriton revolutum (Finlay). × 1–½.
Figs. 23, 24, 26.—Lornia limata n. sp.: holotype. × 4.
Fig. 25.—Erato vulcania n. sp.: holotype. × 5.
interstices; crossed by axials of equal strength and distance apart, nodules formed at intersections so whole surface regularly cancellate. Aperture subcircular.
Apertural diameter, 5 mm.
Siliquaria senex n. sp. (Plate 72, fig. 12.)
Shell tubular, coiled in loose irregular spiral, first whorls missing. Fissure open on last whorl, formed of a series of perforations on penultimate. Sculpture of 12 strong spaced spiral ribs with wider interstices, no ribs on inner side of whorl from fissure downwards for one-quarter of surface each 2 mm. or 3 mm. of length marked by a transverse lamella which produces scaly spines on spiral ribs; numerous fine growth-lines in addition. Aperture subcircular.
Apertural height, 5 mm.; breadth, 4.5 mm.
Locality 831; Esdaile collection.
Turritella tophina n. sp. (Plate 72, fig. 21.)
Shell of moderate size; spire-angle about 20°. Early whorls rather flat but later ones strongly biangulate, concave between angles. Suture deep. Sculpture: earliest whorl seen (0.5 mm. diameter) has 3 spirals, top one weaker than other two, then another weak thread appears above; this arrangement holds for three whorls, then these two merge into a strong posterior angulation; meanwhile lowest spiral merges into strong anterior angulation and second lowest becomes weaker, dying out after several whorls; from then onward there are only the two strong angulations, but surface may have been lined by fine threads, as traces remain. Base with strong keel emerging from suture or just above it, another slightly weaker keel 0.5 mm. below, then fine threads. Aperture quadrate. Outer lip with a very deep narrowly rounded sinus, the apex slightly nearer posterior than anterior angulation.
Height, 28 mm.; diameter, 9 mm. (incomplete).
The neanic stage is the same as the adult T. waihaoensis Marwick, so T. tophina must be a later development of that species. One specimen, an adult body-whorl, has a weak median thread persisting, but it differs from T. waihaoensis in that the whorl is strongly concave as in T. tophina, and the posterior angulation does not have the double thread shown by T. wai-haoensis. The specimen then is probably better considered as a T. tophina in which the sculpture has developed more slowly than usual.
Turritella lornensis n. sp. (Plate 72, fig. 20.)
Shell of moderate size; spire-angle about 20°. Early whorls convex, later flat to slightly concave. Suture shallow. Sculpture: earliest whorl seen (1.5 mm. diameter) has 4 principal spiral threads, anterior two being slightly stronger; broad flat interspaces with a very weak moniliform thread, 2 on posterior space, later there are 3 secondaries on anterior space, middle one strongest; in some specimens adult whorls have primaries and secondaries almost equal in strength, the latter having about doubled their number; generally, however, there are 2 stronger spirals on the anterior swelling of whorl and from 2 to 4 on posterior; growth-lines prominent. Base sharply keeled and spiralled by well-spaced threads. Aperture quadrate. Outer lip deeply and widely sinused, the apex slightly above the middle of the whorl.
Height, 14.5 mm.; diameter, 6 mm. (incomplete).
This species is related to T. carlottae, but is much smaller, has weaker and more spaced primary spirals, also the surface is not crowded with fine threads.
Sigapatella vertex n. sp. (Plate 72, figs. 16, 17.)
Shell small, rounded, convex. Spire lateral, projecting. Whorls 3 including protoconch. Sculpture of dense microscopic waved spiral riblets. Basal plate twisted, with smooth sigmoid margin. Umbilicus well marked, round in cross-section, not penetrating past body-whorl; set well back from the margin of basal plate.
Height, 5 mm.; diameter, 9 mm.
Trivia pinguior n. sp. (Plate 72, figs. 14, 15.)
Shell small, broadly oval, slightly narrowing anteriorly. Sculpture of about 22 narrow strong rounded transverse ribs, with interstices slightly wider; ribs extend upwards from aperture over dorsal surface, but the only specimen does not show to what extent they were interrupted along median line.
Height, 7.5 mm; diameter, 6 mm.
Distinguished from T. zealandica by its much greater obesity.
Mitra n. sp.
Fragments of a Mitra closely allied to inconspicua, but with much more convex whorls. Too imperfect for identification.
Vexillum lornense n. sp. (Plate 72, fig. 13.)
Shell small, fusiform, spire slightly less than aperture. Whorls 5 besides protoconch, slightly convex; body-whorl comparatively large, gradually contracted at base. Protoconch paucispiral, globular with tilted apex. Sculpture obsolete, surface obscurely and finely trellised. Aperture narrow, sides subparallel, angled posteriorly, not notched anteriorly. Outer lip thin, convex, antecurrent to suture, retreating to anterior end of columella, but not contracted to a canal. Columella with 3 oblique median folds.
Height, 6.5 mm.; diameter, 3 mm.
This shell is not by any means a typical Vexillum, and may be nearer Conomitra. Probably a new generic division is required, but the matter can stand over until more material is available.
Erato vulcania n. sp. (Plate 72, fig. 25.)
Shell small, inflated, oval, spire very low. Body whorl convex, obese. Protoconch concealed by enamel. No sculpture. Aperture long, narrow, with subparallel sides, truncated, not notched anteriorly, curved towards apex at top. Outer lip convex, thickened, practically smooth within, ascending to top of penultimate whorl. Columella smooth above, with 2 or 3 rudimentary folds close together at anterior end, traversed by a shallow longitudinal groove.
Height, 4 mm.; diameter, 3 mm.
The columellar folds are so poorly developed that they are seen only on a close inspection of well-preserved specimens. A lens reveals on the inner surface of outer lip a few irregularities which may be rudimentary denticles.
Semitriton revolutum (Finlay). (Plate 72, fig. 22.)
Cymatium revolutum Finlay, Trans. N.Z. Inst., vol. 55, p. 456, pl. 51, figs. 2a, 2b.
Shell of moderate size, fusiform. Spire about equal to aperture and canal. Whorls 5 besides protoconch, convex; body-whorl relatively large, regularly convex contracting gradually to almost straight neck. Protoconch tectiform, of 3 whorls with small nucleus. Sculpture: first, 3 spirals appear and soon after 2 weaker ones posterior to the others; on later whorls 5 spirals approximately of equal strength; interstices equal to spirals anteriorly, narrower posteriorly; axial ornamentation of 20–24 narrow ribs extending across spire-whorls and forming nodules where they intersect spirals, so that surface is divided into a large number of equal squares; fine spiral threads occupy interspaces, about 3 in each, these also regularly trellised by fine growth-lines; body-whorl has 19 primary spirals, interspaces of those below line of suture with one secondary stronger than the others, 4 more close spiral threads anterior to these on neck. Obsolete varices at about each two-thirds of a whorl. Suture well marked. Aperture subrhomboidal, produced into an almost straight wide canal not notched anteriorly. Outer lip straight, thickened, dentate within. Columella straight with 2 strong oblique folds. Inner lip not calloused, so that spiral sculpture enters aperture; 2 or 3 irregular denticles anterior to columellar folds.
Height, 23 mm.; diameter, 11 mm.
This genus is an Australian one founded on Plesiotriton dennanti Tate from Cape Otway. Cossmann in founding the genus (1903, p. 102) describes the protoconch as “globuleuse, paucispirée, à nucleus assez gros et dévié,” but this does not agree with our specimen. Since the agreement of the shells is so close in other matters, it may be that some mistake due to imperfect preservation has been made.
Ficus transennus Suter belongs to this genus; indeed, as the type is an internal cast it is scarcely possible to be certain about the specific difference of S. revolutum. The former is considerably larger, and until more material is obtained it is safer to keep the two species apart.
The manuscript of the present contribution was written before the publication of Mr. Finlay's paper; in it this shell had been described as new, and the writer is indebted to Mr. Finlay for pointing out the agreement with his species. As the Waiarekan shell is better preserved than the types, the description and figure have not been deleted.
Clavatula humerosa n. sp. (Plate 72, fig. 19.)
Shell rather small, fusiform. Spire equal to aperture and canal. Whorls 5 below protoconch, with short sloping shoulder below which they are almost cylindrical; body-whorl with rapidly contracted base and fairly long lightly twisted neck. Protoconch conoidal of about 4 smooth whorls. First succeeding whorl with about 12 axial ribs raised into strong nodules on shoulder, on next whorl ribs decline into nodules which disappear after another turn, base of body-whorl with numerous fine close spiral threads. Aperture narrowly ovate, produced into moderately long wide canal which is not notched at end. Contour of outer lip uncertain. Columella straight. Smooth thin inner lip extending down along narrow inner margin of canal.
Height, 11.5 mm.; diameter, 5 mm.
Until the outer lip is known the generic position will be uncertain. The two species which Suter classed under this genus, C. neozelanica and C. mackayi, are not likely to be confused with the new one. The former has a deep anterior notch and fasciole and is an Austrotoma; the latter has flat whorls with a bordered suture and a lightly sinuous outer lip.
Turricula esdailei n. sp. (Plate 72, fig. 18.)
Shell small, fusiform. Spire equal to aperture and canal. Whorls 4 besides protoconch, with high concave shoulder, straight below; body-whorl fairly quickly contracting to moderately long slightly-twisted neck. Protoconch tectiform, of 5 whorls, nucleus minute, last half-whorl with 6 faint spirals crossed by weak axials. Sculpture of 15 strong axial ribs barely showing on shoulder and becoming weak on base, interstices of equal width; spiral cords 4 or 5 on spire-whorls, about 15 on body-whorl have wide interstices with a fine threadlet, shoulder with about 8 fine close spirals, spirals are trellised and rendered moniliform by numerous raised growth-lines. Aperture ovate, channelled above, produced below into a fairly wide canal not notched at base. Outer lip thin, with an arcuate sinus on shoulder, then sweeping forward in middle and base of body-whorl. Columella straight. Inner lip thin.
Height, 15 mm.; diameter, 7 mm.
The generic location is only provisional. The ornamentation and outer lip are similar to those of Austrotoma, but there is no anterior notch to the canal.
Lornia n. gen. Type, Lornia limata Marwick.
Lornia limata n. sp. (Plate 72, figs. 23, 24, 26.)
Shell small, thin, sinistral, planorbid. Whorls rather plump; body-whorl inflated, expanding round aperture; apical whorls sometimes slightly sunken. No sculpture. Aperture oval, entire. Umbilicus large, but not excessively so.
Height, 2 mm.; diameter, 4 mm.
The relationship of this shell is rather puzzling. Another species occurs in the Paleocene of Wangaloa.
Cossmann, M. 1903. Essais Paléoconch. Comp., vol. 5.
Marwick, J. 1924. N.Z. Journ. Sci. & Tech., vol. 6, Nos. 5 and 6, p. 280.
Suter, H. 1921. N.Z. Geol. Surv. Pal. Bull. 8.
Thomson, J. A. 1916. Trans. N.Z. Inst., vol. 48.