regarded as the index-fossil or fossils of the zone, or by concentrations of forms, each group being in a certain stage of evolution (cf. Elles 1925, 1933). The actual divergence from the British practice is not great, however, and seems in large measure to be authorised by Dr. Elles's dictum (1925): “There does not appear to be any justification for focussing too much attention on the index-fossils rather than on the assemblage which is the determining factor.” Indeed, a slight change in the phrasing of the definitions of certain of the Victorian zones may bring them almost into line with the theoretical requirements, without any change being made in actual practice.¹¹ Such modifications will be attempted below in so far as they may refer to the New Zealand succession. It may be noted, however, that the lithology of the New Zealand rocks herein described is not quite the same as that of the Lower Ordovician rocks of Victoria. In the latter country the graptolites occur very frequently in shales intercalated among relatively thin masses of sandstone, while in New Zealand the fossiliferous shales are subordinate, occur less frequently, and are separated by relatively wide bands of greywacke.

Detailed Stratigraphy of the Lower Ordovician Rocks in Fiordland.

General.—In two portions of our region, namely, the western shores of Cape Providence and the southern shore of Preservation Inlet, there is exposed a long and comparatively little disturbed sequence of fossiliferous and unfossiliferous beds, which permits the determination of the succession of the graptolite-assemblages and the estimation of the approximate thicknesses of the strata in which they occur. The apparent faunal sequence in these two sections agrees so closely with that already determined in Victoria as to justify the conclusion that the simplicity of structure is real, and the deduced sequence is correct. Out of twenty-eight localities where recognisable graptolites have been obtained, twenty-three lie in such a position that their stratigraphical horizons are obvious, while the horizons of four of the remainder can be determined satisfactorily on palaeontological grounds.

The Cape Providence West Section. The most complete section is that on Cape Providence. It was traced along its outer coast for nearly two miles north-west of the Cape. We commence the description at its northern end (see Fig. 1), where the oldest rocks of the series are exposed in a little bay south-west of a prominent group of three stacks, of which the largest is in the form of an arch (see Part 1, Plate 42A). These rocks are dark, slabby, siliceous greywacke interbedded with narrow bands of cherty, jointed and not very fissile black or grey slate, and show evidence of current-bedding on weathered surfaces. The beds are gently arched or irregularly undulating with an average northerly dip of 8°–15°, though further north the dip increases (see Part II Plate 3, Fig. B). They show local sharp contortion resulting from dragging along the plane of an unimportant fault, and are cut by vertical joints, the most marked

of which run almost meridionally. They contain few quartz-veins, though near the stacks there is a veinlet of quartz with pyrites, chalcopyrite, and a trace of stibnite. Followed southwards, these undulating beds may be seen to lie on the summit of an anticline beyond which the southward dip steadily increases.

Text-Figure 1.—Geological map of Cape Providence Peninsula.

At a point (Locality 1) about 300ft. stratigraphically above the lowest observed beds, a small group of fossils was obtained yielding Tetragraptus decipiens (5)¹ as the only determinable form, associated with indeterminate species of Bryograptus (2) and Clonograptus (3), sponge-spicules and obscure Obolellids. On this follows 160ft. of greywacke, above which is a band of crushed black pyritous shale

(Locality 2) which yielded fragments of Dictyonema macgillivrayi (2), Clonograptus cf. magnificus (3), Bryograptus (?) antiquus (1), T. decipiens (2) with Rhinopterocaris cf. bulmani and Protospongia sp. A wide shatter-belt containing fragments of slate, quartzite and greywacke follows, and beyond this the section is obscured. Assuming that the formation of the shatter-belt was not accompanied by much relative displacement of the formations on either side, we may allow about 100ft. for the thickness of the strata in this portion of the section. A thickness of one hundred feet of quartzite follows on the shatter-belt, and forms a massive band which rises into a small stack. There succeeds on this a thickness of 160ft. of spotted mudstones of medium grain-size interstratified with finer-grained slaty layers and thin bands of quartzite. There is frequent evidence of slipping along the bedding-planes with the production of slicken-sides. Quartzites 300ft. thick then appear and are succeeded by a narrow crush-zone, beyond which are silky slates interbedded with thin layers of current-bedded quartzite. At Locality 3, about 1200ft. above the base of the section, a thin bed of black slate yielded the following forms:—Dictyonema macgillivrayi (3), Bryograptus (?) antiquus (2), B. (?) antiquus var. inusitatus var. nov. (1), B. clarkei (6), B. hunnebergensis¹ (1), B. cf. lapworthi (2), B. victoriae (3), abundant examples of T. decipiens (17) and one of its variety T. decipiens var. bipatens (1) and of Didymograptus taylori (1) with Caryocaris marri, C. wrighti, Hymenocaris bensoni, and Rhinopterocaris bulmani.

A band of carbonaceous slate 70ft. higher in the series (Locality 4) yielded Clonograptus spp., B. (?) antiquus var. inusitatus (2), B. hunnebergensis (1), T. decipiens (2), D. taylori (1), and Caryocaris wrighti.

So far there can be no doubt that the fauna corresponds with that characterising the Middle Lancefieldian or L3 zone of the Victorian succession. The correlation in regard to the immediately succeeding beds is less definite.

The fossiliferous slate of Locality 4 is followed by fine-grained greywacke-mudstones displaying slumped bedding-planes on weathered surfaces, and yielding place to more or less shattered massive bands of quartzite rising from the shore in small stacks; they are seamed with irregular quartz-veins and include bands of black or grey unfossiliferous slates. At Locality 5, about 1800ft. above the base of the section, a narrow band of black slate yielded Clonograptus tenellus var. kingi² var. nov. (1), C. rigidus (2), T. decipiens (1), T. quadribrachiatus (3), and indeterminate forms. Of these forms the second, third, and fourth may occur in either the L3 or the L2 beds of Victoria, though the last, which is characteristic of higher beds, is very rare in the L3 zone. C. tenellus var. kingi seems, however, to be confined to the higher portion of the Lancefieldian Series, as will appear below. The bed at Locality 5 containing this small group of graptolites will, therefore, be assigned to the L.2 zone, rather than the L3, but must occur near the lower limit.

There follows on this a thickness of nearly 1000ft. of greywacke and greywacke-mudstone with several thin bands of black slate which have yielded no fossils. The highest band of slate is grey, pyritous, and almost vitreous. A marked fracture now crosses the section, and along its course the sea has cut a channel, “the Valve,” which extends up to the base of the coastal cliff, and can be crossed only when the tide is low. A sharp change of dip across this fracture-zone suggests that a noteworthy displacement of strata has occurred here. The beds immediately to the south have a distinctive Lower Bendigonian fauna. It thus appears that the thousand feet thickness of apparently unfossiliferous beds exposed north of “the Valve” comprise the strata that are coeval with the L2 zone of Victoria, together with any that are the equivalent of the L1 zone. Fortunately, in the second continuous section, that south of Preservation Inlet, the beds extending for a thousand feet below the horizon of the basal Bendigonian fauna, contain a distinctive fauna (differing from that of the L3 zone), which may subsequently be found throughout the supposedly L2 beds on Cape Providence.

The sequence of beds traced south-eastwards from “the Valve” includes a thickness of about 800ft. of strata with rapidly changing faunas displayed in rocky bars jutting obliquely from a boulder-beach. Careful surveying will be necessary before accurate measurements can be made of the thicknesses of the zones present, so that the figures given herein have but a qualitative accuracy.

Immediately south of “the Valve” are massive quartzite, dark unfossiliferous pyritous slate and siliceous greywacke, in all about 100ft. thick. Then at Locality 6 a thin band of black slate yielded Clonograptus tenellus (1), B. simplex (2), B. cf. lapworthi (1), Tetragraptus approxanatus (4), T. decipiens (1), T. fruticosus with four branches (3), T. quadribrachiatus (1), Didymograptus latus (1), D. extensus and early transients towards D. nitidus (4) (cf. Elles 1933), D. simulans (2), D. cf. taylori (2), and Phyllograptus sp. an association of species indicative of the lowest Bendigonian zone (B5) of Victoria.

Quartzite and greywacke with a few thin bands of slate following on this zone have yielded no fossils in situ, but from their massive seaward-projecting extension may have come a pebble in which field-determinations indicated the presence of T. fruticosus 4 br., with T. quadribrachiatus, T. pendens, Goniograptus macer, and Didymograptus aureus, an association characteristic of Zone B4 in Victoria. Unfortunately, this pebble was mislaid, and has not been critically re-examined. That the B4 zone should occur, and be confined within narrow limits is rendered very probable by the presence of the B2 fauna at Locality 7, stratigraphically about 300ft. above the B5 beds at Locality 6.

The B2 beds of Locality 7 contain the following forms: Goniograptus macer (1), Sigmagraptus laxus (2), T. fruticosus 3 br. (12), T. fruticosus 2 br. (2), T. harti (1), T. pendens (1), T. serra (3), T. similis (6), D. extensus (5), D. nitidus (7), Phyllograptus angustifolius (6), and P. spp. (3) with Diplograptus (?) cf. inutilus (1) and Cryptograptus (?) antennarius (1). There is a small

indefinite form which is perhaps an early stage of Isograptus caduceus, though it is impossible to separate it with certainty from the Tetragraptids.

About a hundred feet above the fossiliferous bed at Locality 7 there occurs another at Locality 8 which yielded a very different and interesting assemblage containing several species either new or hitherto unknown in the Australasian region. The latter are marked with an asterisk in the following list: Clonograptus abnormis (1), Goniograptus sp., Sigmagraptus laxus (1), T. fruticosus 3 br. (10), T. harti (8), T. pendens (3), T. serra (6), T. similis (3), T. taraxacum* (1), T. whitelawi (9), Didymograptus artus* (1), D. extensus (2), D. gracilis (1), D. harrisi sp. nov. (1), D. nicholsoni var. aotea var. nov. (1), D. nicholsoni var. planus* (1), D. nitidus (4), D. nitidus-patulus (1) a transient form (cf. Elles 1933), and small obscure forms resembling in some respects Isograptus caduceus var. primula (2), together with Hymenocaris lepadoides and Rhinopterocaris maccoyi. Though D. protobifidus has not been found here, this fauna is sufficiently distinct from that at Locality 7 to justify its relegation to the B1 zone.

Above this fossiliferous bed there succeeds about a hundred feet of alternating greywacke and slate on which there rests at Locality 9 a band of slate containing the following forms: Sigmagraptus sp. (1), Tetragraptus amii (1), T. fruticosus 3 br. (55), T. fruticosus 2 br. (1), T. harti (1), T. quadribrachiatus (5), T. serra (19), T. similis (4), T. whitelawi (1), Didymograptus protobifidus (3), D. ellesi (1), D. extensus and transients (13+), D. nitidus (1), Isograptus caduceus var. primula (?) (a very doubtful determination), Phyllo-graptus angustifolius (5), P. cf. typus (2), P. spp. (16), together with Caryocaris sp., Lingulocaris cf. acuta and Rhinopterocaris maccoyi. This association is clearly that of the B1 beds of Victoria.

Rather less than a hundred feet stratigraphically above this there occurs at Locality 10 a fauna characteristic of the lowest portion of the Castlemainian Series in Victoria, Zone C5. It therefore appears that the whole thickness of the Bendigonian Series on Cape Providence must be comprised within about 500–600ft. of strata. Though this is much less than the thickness of the strata in the type-district of Bendigo in Victoria, it has been shown that three and probably four of the five zones in the Bendigonian Series are recognisable at Cape Providence.

The slates at Locality 10 have yielded the following forms: Clonograptus sp. (1), Didymograptus artus (2), D. protobifidus (6), Isograptus caduceus var. primula (1), Phyllograptus spp. (5), Caryocaris cf. marri, and an indefinite possibly orbiculoid brachiopod. The abundance of D. protobifidus is characteristic of the C5 zone. The immediately adjacent fossiliferous bed at Locality 10a, however, has not yielded this form, but only a small and indeterminate assemblage, viz., Bryograptus sp. (1), Tetragraptus serra (1), T. similis (1), Isograptus caduceus var. primula? (1), and Phyllograptus spp. (4).

A thickness of about a hundred feet of siliceous greywacke covering these beds is succeeded by fossiliferous slate which at

Locality 11 yielded the following forms: Dichograptus octobrachiatus (2), Tetragraptus similis (4), Didymograptus affinis (2), D. bidens (1), D. ellesi (1), D. nitidus-patulus (1), a transient form, D. protobifidus (1), Isograptus caduceus var. primula (5), Phyllograptus angustifolius (3), and Strophograptus trichomanes (1), an association which, as will appear, seems to be indicative of the higher portion of the C5 zone.

About fifty feet above the last bed there were obtained at Locality 12 the following: Tetragraptus quadribrachiatus (2), T. similis (3), T. woodi (1), Didymograptus dependulus (1), Isograptus caduceus var. lunata (6), Phyllograptus angustifolius (4), Diplograptus cf. longicaudatus (2) and Climacograptus (?) sp. together with Caryocaris marri, Hymenocaris (?) sp., and Rhino-pterocaris maccoyi. This association of graptolites is indicative of a middle Castlemainian age about the equivalent of the C4 zone (cf. Harris and Keble 1932). It lies closely adjacent to the axis of a northerly pitching syncline and is the highest of the fossiliferous beds exposed on the western side of Cape Providence.

Verbal accounts kindly given by Professor Park indicate that the bulk if not all of the collection of graptolites made by him on Cape Providence (Park 1922, Keble 1927) was derived from the cliffs behind the storm-beach near the synclinal axis, approximately at the point P on the map (Fig. 1). This collection ¹ comprised the following forms: Clonograptus sp. (2), Goniograptus sp. (1), Dichograptus octobrachiatus (2), Tetragraptus amii (3), T. pendens (?) (3), T. quadribrachiatus (2), T. serra (13), T. similis (6), T. whitelawi (3), Didymograptus adamantinus (4), D. bidens (2), D. sp. nov.? aff. bidens (1), D. extensus (6), D. cf. gracilis (1), D. procumbens (5), D. protobifidus (17), Isograptus caduceus var. primula (22) and var. lunata (2), Phyllograptus cf. angustifolius (3) P. spp. indet. with Caryocaris marri, C. wrighti, Rhinopterocaris bulmani and R. maccoyi. Possibly (according to Professor Park) some of these fossils may have been obtained from pebbles on the beach, for it is noteworthy that D. adamantinus has not hitherto been found in situ in so high a zone as is indicated by the rest of the assemblage. The nature of the matrix in which this form is preserved gives, however, no suggestion that it was derived from a different band from that containing the remainder of the collection. The abundance of I. caduceus in association with D. protobifidus may be taken as indicating that this assemblage was derived from the upper portion of the C5 zone (approximately the horizon of Locality 11) rather than the C4 zone to which it was formerly assigned.

About four hundred yards south-east of the synclinal axis, after a stretch of obscuring beach, the fossiliferous beds of the B1 zone reappear dipping to the north-west. A collection made at Locality 13, seventy yards east of the little creek shown on the map (Fig. 1) contains the following:—Bryograptus sp. (1), Goniograptus crinitus (1), G. macer (2), T. amii (1), T. fruticosus 3 br. (12), T. pygmaeus (1), T. quadribrachiatus (1), T. serra (4), T. similis (4), T.

taraxacum (1), Didymograptus artus (1), D. extensus and transients into D. nitidus (11), and D. protobifidus (1). A comparable fauna was obtained at Locality 14 about 20yds. distant in beds strati-graphically 40ft. below those at Locality 13. The fauna at these two localities when taken together is clearly comparable with that at Locality 9. On plotting to scale the recorded information, it appears that the syncline must be broken by a fault with a downthrow on the south-east amounting to several hundred feet.

The lower members of the Bendigonian Series may eventually be found south-east of Locality 14, though this portion of the sequence seems to be crossed by a more or less meridional fault, the position of which has not been determined. This portion of the coast was, however, examined very rapidly, and no graptolites were seen in the few slaty bands among the massive greywackes and quartzites near the point of Cape Providence.

The Preservation Inlet Section. The shores of Preservation Inlet westward from Kisbee Beach across Otago's Retreat to Coal Island exhibit a somewhat dislocated succession of beds, which furnish a sequence in a large measure complementary to that exhibited on Cape Providence (Fig. 2). This is the region wherein McKay first noted the presence of graptolites. The position of the granite boundary shown in the map and section is taken from McKay's map, and the structure indicated for a mile westward thereof is largely hypothetical. The observed section commences at the anticline by the southern end of Kisbee Beach, and continues uninterruptedly westward to Powell's Beach, exposing slate bands 30–100ft. thick interlaminated with thin bands of quartzite, and alternating with thicker bands of siliceous greywacke or quartzite. The dip varies between 25° and 70° to the west, and the strike between N.10°W. and N.20°W. Fossils have been found at four localities, viz., 20, 21, 22, and 23, respectively 1200, 600, 400, and 200ft. stratigraphically below the base of the Bendigo Series, near the fossiliferous bed at Locality 24. Thus the strata between Localities 20 and 23 are probably equivalent to the thousand feet of apparently unfossiliferous rocks immediately below the Bendigonian rocks on Cape Providence, which follow above the fossiliferous Middle Lancefieldian (L3) zone forming the northern portion of that section. It is therefore noteworthy that these higher Lancefield rocks at Kisbee Beach contain an assemblage of forms distinctly different from that in the Middle Lancefield beds of Cape Providence. The distribution of the forms as tabulated on page 260 shows that the higher Lancefield beds are characterised by the abundance of Clonograptus tenellus var. kingi and Bryograptus hunnebergensis, which though occurring but rarely in the Middle Lancefield beds, form matted aggregates in the Upper Lancefieldian. B. (?) antiquus var. inusitatus var. nov., also rare in the Middle Lancefield beds, is more abundant in the Upper Lance-fieldian, in which B. simplex also enters. There is, however, no trace of Tetragraptus acclinans or T. approximatus, the entry of which marks the L1 beds of Victoria. It will therefore be assumed that our higher Lancefield beds are the equivalent of the L2 zone of Victoria, and that the L1 zone if present is thin and as yet unrepresented by fossiliferous strata.

At Locality 24 is a dark grey fissile slate containing within a thickness of six inches abundant and well-preserved fossils comprising the following:—Bryograptus clarkei (2), B. spp. indet. (3), Tetra-graptus acclinans (8). T. approximatus (17), T. chapmani (3), T. decipiens (8), T. decipiens var. bipatens (9), T. fruticosus 4 br. (17), T. fruticosus var. conferticosus (3), T. pendens (1), T. postle-thwaitei (33), T. quadribrachiatus (85), T. spp. indet. (14), Didymograptus cf. aureus (2), D. bartrumi sp. nov. (1), D. extensus and a transient towards D. nitidus (2), D. latus (1), D. cf. simulans (1) and D. taylori (1). This overwhelmingly Tetragraptid fauna containing only the four-branched form of T. fruticosus is definitely referrable to the B5 zone of the Victorian sequence.

Above this basal Bendigo bed are flinty argillites and siliceous greywackes within which there is a sheared zone resulting from slipping along a bedding-plane, probably connected with the folding of the adjacent syncline. This shear-zone or “back” has been much mineralised with partial replacement of the finely granulated friction-breccia by finely laminated quartz, associated with calcite, pyrites, limonite, and wad. West of this there follows massive grey quartzite seamed by small irregular veins of quartz, exposed for over 200yds. along the shore, forming the small islet, and bent into a sharp syncline of which the western limb dips at 75° eastward.

The westward sequence of beds is then obscured for 500yds. by Powell's Beach, but on the western side of this there is a sharp anticline near the axis of which, at Locality 25, there were obtained forms classed in the field as Bryograptus sp. and Clonograptus sp. They were unfortunately mislaid, but the containing bed may, nevertheless, be assigned with considerable probability to the L2 zone.

At the headland between Powell's Beach and Te Oneroa the argillite is invaded by a sill of dolerite about 30ft. thick, with a fine-grained chilled margin visible at the eastern contact, but cut off on the west by a fault which brings siliceous greywacke against the dolerite. A second fault occurs about a hundred yards further west, bordering a sharp syncline, on the limits of which siliceous beds alternate with argillites containing indistinct traces of grapto-lites. A very massive band of siliceous greywacke forms the bluff immediately north-east of Te Oneroa Beach, and seems to be cut off on its southern side by a steeply-dipping fault running to the E.N.E., the northern wall of which has been laterally displaced eastwards. The sluiced floor of Berg's Claim nearby shows spotted silicified or hornfelsic greywacke enclosing thin bands of pyritic slate dipping E.N.E. at 50°.

At a horizon possibly somewhat lower than the last rocks a fossiliferous bed is exposed at Locality 26 in the lowest adit of the Morning Star Mine (about 170ft. above Te Oneroa Beach). From the mine-dump a small but very interesting collection of forms was obtained, viz., Clonograptus cf. flexilis (1), C. tenellus (1), Bryograptus victoriae (5)¹¹, Tetragraptus decipiens (4), Didymograptus taylori (2), and Triograptus otagoensis sp. nov. (13). This last species belongs to a rare three-branched genus hitherto known only in

Norway. With these is a small brachiopod Leptobolus novae-zealandiae sp. nov. The horizon of this fossiliferous bed is probably within the upper portion of the L3 zone. It is perhaps the bed in which McKay noticed the presence of graptolites. It is probable also that Mr J. S. Nicol's small collection of graptolites, presented to the Otago University Museum and described by Hall (1915), comes from near this zone. It comprised Bryograptus “sp. nov.” (= B. hunnebergensis), Clonograptus tenellus, C. tenellus var. callavei, C. sp. nov. and Tetragraptus decipiens. In the Canterbury Museum, a few specimens, also obtained from this neighbourhood (Te Oneroa Beach), and presented by Mr Nicol in 1902, comprise a water-worn Clonograptus cf. rigidus (or sp. nov. of T. S. Hall), and obscure traces of T. decipiens and Bryograptus sp.

The succession of beds is concealed by Te Oneroa Beach for nearly a thousand yards further west, but is then continued by a sharp syn-cline composed of shattered quartzite and thin bands of argillite in which, at Locality 27 near a large bluff, there was obtained the following collection: Bryograptus (?) antiquus var. inusitatus (1), B. hunnebergensis (12), B. victoriae (10), Tetragraptus decipiens (3), Didymograptus cf. pritchardi (1), and indefinite fragments of a small Dictyonema. On account of the abundance of Bryograptids the bed may be assigned to Zone L2. No other fossils were found on the eastern side of Otago's Retreat, though perhaps this zone extends southwards to the head of Sealer's Creek where McKay found fossils, and northwards into Crayfish Island. A great quartzite-bluff 1200yds. south-west of Te Oneroa Beach is directed towards the north-eastern end of Coal Island, but apparently there has been considerable dislocation of the strata beneath Otago's Retreat, for it does not reappear on this island. On Coal Island there is a fossiliferous bed at Locality 28 near Moonlight Point, which contains T. decipiens as the only determinable form, together with indeterminate specimens of Bryograptus and Clonograptus. Probably this bed belongs to the L2 zone, for it appears to lie less than a thousand feet below the base of the Bendigonian.

For a short distance westward the succession is obscured by Moonlight Beach, at the back of which there is a gravel-terrace about fifty feet high. At the western end of the beach thin fossiliferous bands occur at Localities 29 and 30, which are separated by about twenty-five feet of quartzite. Together they contain Clonograptus sp., Goniograptus thureaui (2), G. sp. indet., Tetragraptus fruticosus 3 br. (13), T. pendens (1), T. serra (7), T. similis (4), Didymograptus similis (9), a small form resembling Isograptus caduceus var. primula (2), Phyllograptus anna (5), P. cf. typus (2), and Diplograptus (?) cf. inutilus (1). The horizons to which these bands must be referred are probably close to that occupied by the beds at Locality 7 on Cape Providence, i.e., in the B2 zone.

To the north-west of these beds is a rather disturbed strip of country, and at Locality 31, two hundred yards away in a direction almost along the strike, and therefore probably but little higher in the sequence, a small collection of graptolites was obtained from a contorted band of slate in which T. serra (1), T. whitelawi (1), and D. nitidus (2) were the only recognisable forms. This strip

extends into a little point, and about a hundred yards further west is a small promontory marked as Locality 32. Here an extensive collection was made from a richly fossiliferous bed, the following forms being obtained: Tetragraptus amii (12), T. harti (2), T. serra (26), T. similis (18), T. taraxacum (3), Didymograptus cf. euodus (1), D. extensus (2), D. cf. gracilis (1), D. mundus (3), D. nitidus (3), D. protobifidus (92), D. similis (2), Isograptus caduceus var. primula and forms tending towards var. lunata (30), Phyllograptus angustifolius (54), P. cf. ilicifolius (1), P. cf. typus (1) and Diplograptus (?) cf. inutilis, together with Hymenocaris (?) sp. and Rhinopterocaris maccoyi. The abundance of D. protobifidus indicates that this bed belongs to the lowest Castlemainian zone C5, approximately coeval with the bed at Locality 10 on Cape Providence, but probably slightly older than that which yielded Professor Park's collection in which Isograptus caduceus is more abundant than D. protobifidus.

The beds which overlie this fossiliferous band are concealed beneath a gravel beach west of Locality 32, and are followed by quartzites alternating with argillites appearing here and there above the storm-beach. A hasty examination failed to reveal any fossiliferous beds among them. If they are all of Castlemainian age, a thickness of about 1800ft. of this series is present in Coal Island.

The Northern Shore of Preservation Inlet. Traced westwards from Cavern Head, the rocks are normal greywackes, argillites or fissile slates, though there is an increasing tendency towards a phyllitic habit. The beds have been bent into a major anticline and syncline with a general southward pitch, and these folds have been complicated by minor puckerings, and broken by several faults and shatter-zones. Te Whara, a group of islets at the end of a long sand-spit (Locality 18), consists chiefly of quartzite, but a band of slates therein contains indeterminate Tetragraptids. On the mainland at Locality 19, adjacent to these islands, two large masses of rock nearly twenty feet in diameter, but not in situ, yielded a fauna characteristic of the L2 zone, viz., Clonograptus tenullus var. kingi (8), Bryograptus hunnebergensis (10), B. simplex (3), Dichograptus octobrachiatus (1), Tetragraptus decipiens (7), Didymograptus eocaduceus (2) and Rhinopterocaris maccoyi var. tumida var. nov., together with small obscure obolid brachiopods.

Traced north-eastwards from Cavern Head to the granite in Brokenshore Bay, the rock is chiefly more or less siliceous greywacke. Argillites are present in very small amount, and have not been found to contain any fossiliferous layers. Nor have fossils been found in the argillites which, interstratified with greywacke, compose many of the islets in Preservation Inlet. The structural and petrographical features of these rocks have already been discussed in Parts I and III of this series.

Gulches Peninsula. The Lancefield rocks just described and those on the eastern side of Southport seem to be represented in more metamorphosed form in the Garden Islets. These are separated by an important fault from the northern point of Gulches Peninsula, so that the slightly altered greywacke and argillite which occur in

the latter may belong to a higher stage in the stratigraphical sequence than the Lancefield rocks further east. The sheared argillites of the north-eastern shores of the peninsula yielded Caryocaris sp. and Rhinopterocaris sp., whilst those on the north-western shore (Locality 17) contained (with a few indeterminate graptolite-remains) Caryocaris marri, C. minima sp. nov., C. wrighti, Rhinopterocaris bulmani and R. maccoyi together with traces of a sponge probably allied to Megastylia¹. These do not, however, afford much information as to precise age of the containing beds.

The Eastern Coast of Cape Providence. The Cape itself, and the “Sugarloaf” stack standing out from it are constituted by a thick bar of quartzite which is fractured by joint-planes usually running about E.10°N., and contains thin veinlets of quartz either parallel or perpendicular to this direction. The dip and thickness of this bar of quartzite have not been ascertained, nor is its relation to the adjacent feature mapped as a “probable fault” yet clear, but it is assumed that the strike of the bar is about N.N.W. The beach to the east of the main cape conceals the outcrop of alternating argillites and greywackes about 400ft. thick, in the lower portion of which is a bed projecting seaward as a reef which contains an abundance of fossils (Locality 15), the most notable form obtained being a specimen of Dictyonema macgillivrayi which must originally have been over fourteen inches in diameter. In addition to this, the following species were collected: Clonograptus flexilis (1), C. tenellus var. kingi (6), Bryograptus divergens (3), B. divergens var. subsimus (3), B. hunnebergensis (12), B. victoriae (2), Tetra-graptus decipiens (27), T. decipiens var. bipatens (6), and T. postle-thwaitei (2) together with Protospongia cf. oblonga and Caryocaris wrighti, C. spp. indet., and Rhinopterocaris maccoyi. For reasons discussed below this assemblage is indicative of a low horizon in the L2 zone. The containing beds dip at 70° to the W.S.W., so that they lie just above the band of quartzite sixty feet thick that makes up the eastern bluff of Cape Providence, where it is pierced by a natural archway.

About 300ft. stratigraphically below this quartzite there occurs at Locality 16 a second fossiliferous layer, a sooty, imperfectly fissile slate, in which the only striking form noted was a large but indeterminable Clonograptus, the few remaining forms being badly preserved, but apparently indistinguishable from those at Locality 15. Unfortunately the collections from Localities 15 and 16 were not kept separate, so that any determinable form from Locality 16 will have been recorded in the above list from Locality 15.²

If the succession of beds which follows to the north-east of Locality 16 be not broken by faulting, there must be present here a thickness of about 1200ft. of Middle Lancefield beds dipping steeply to

(H. and K.), forms displaying features indicative of a rather later development than the two species first named (fide Dr. Elles), and which occurring together with Staurograptus diffissus (H. and K.) characterise the lowest fossiliferous zone (L4) at present recognised in the Lancefield Series in Victoria (Harris and Keble 1928). We may provisionally define it as the zone of D. campanulatum and D. scitulum, extending from the horizon of entry of Staurograptus to that of the entry of Tetragraptus, which in its lowest occurrence is associated with the paracmaie expression of Staurograptus diffissus.

The L3 zone, which is very widespread in Victoria, is the oldest yet recognised in New Zealand. It is characterised in New Zealand by the relative abundance of Tetragraptus decipiens, the zone fossil, in association with Dictyonema macgillivrayi, Bryograptus (?) antiquus, and B. (?) antiquus var. inusitatus, B. clarkei, B. hunnebergensis, and rarely B. cf. lapworthi, Clonograptus cf. flexilis, C. magnificus, C. tenellus, C. tenellus var. callavei, T. decipiens var. bipatens, and Didymograptus taylori are also present in this zone. For a brief period probably in the higher portions of the series there flourished in New Zealand the interesting form Triograptus otagoensis, a species of a genus hitherto known only in the neighbourhood of Oslo, Norway. A thickness of over a thousand feet of strata exposed on Cape Providence belongs to this zone.

The distinction between the L3 and L2 zones is not clearly marked in Victoria, where it is indeed a matter of some difficulty (Harris and Keble 1932, p. 27). In our region, however, the entry in abundance, sometimes in densely matted aggregates, of Bryograptus hunnebergensis and Clonograptus tenellus var. kingi, the zone fossils, satisfactorily characterises the L2 zone. B. divergens, B. divergens var. subsimus, and B. simplex also appear, while B. (?) antiquus, B. (?) antiquus, var. inusitatus and B. clarkei remain subordinate, T. decipiens and its variety bipatens continue, while T. quadribrachiatus and T. postlethwaitei make their appearance scantily. Clonograptus rigidus, Dichograptus octobrachiatus, Didymograptus eocaduceus, and D. cf. pritchardi also occur sparsely in this zone. Dictyonema macgillivrayi, here as in Victoria, extends into the lower portion only of this zone. The sharpness of its distinction from the underlying L3 zone may be gathered from Table I herewith. A thickness of over a thousand feet of strata both at Cape Providence and near Kisbee Beach, Preservation Inlet, belong to the L2 zone, which has recently been found to occur also in the north-western extremity of the South Island of New Zealand.

The L1 zone in Victoria comprises the strata lying between the horizon of entry of Tetragraptus approximatus and that of T. fruticosus. T. acclinans also enters into this zone, whilst Clonograptus tenellus and T. decipiens continue, but the Bryograptids have become much less numerous. No such assemblage of forms has yet been proved to occur in New Zealand, the typical L2 assemblage without T. approximatus being present up to within 200ft. of the beds characterised by the basal Bendigonian fauna. It appears, therefore, that the L1 zone is either very thin, or unrepresented in the New Zealand succession.

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The Bendigo Series. Bendigonian rocks are well developed in south-western New Zealand, and are characterised pre-eminently by the presence of Tetragraptus fruticosus. The beds are displayed both on Cape Providence and in Preservation Inlet, but are in all only 500–600ft. thick. The lowest or B5 zone is marked by the association of T. approximatus with early four-branched members of T. fruticosus characterised by the widely spread position of its stipes. At Locality 6 on Cape Providence these forms are associated with Clonograptus tenellus, Bryograptus simplex, T. decipiens, and T. quadribrachiatus, which have come up from the Lancefieldian, the

last being still subordinate, and early extensiform Didymograptids appear sparingly. Lying perhaps¹ at a slightly higher horizon is the richly fossiliferous bed at Locality 24, in which T. quadribrachiatus has become the dominant form with T. postlethwaitei, which had appeared in L2, second in order of abundance. The four branched T. fruticosus now exhibits its mature pendent form, and has given rise to a new variety, conferticosus. A group of other species including T. acclinans, T. chapmani, T. pendens, and a few horizontal Didymograptids, D. cf. aureus, D. bartrumi sp. nov., D. latus, D. cf. simulans, and transitions between D. extensus and D. nitidus. T. decipiens makes its last appearance in this zone, and the Clonograptids and Bryograptids are now rare.

The B5 zone, which may be defined as that of T. approximatus and T. fruticosus, is apparently not more than 200ft. thick in the region studied, and is characterised pre-eminently by the concentration of the horizontal Tetragraptids.

The B4 zone in New Zealand is so far represented by a pebble only. It is marked in Victoria by the entry of reclined Tetragraptids and Phyllograptids, the great increase in extensiform Didymograptids and the appearance of Goniograptids. Neither T. acclinans, T. approximatus, nor T. decipiens have been found in this zone. D. aureus, which in Victoria has not been found above B5, is present in the single New Zealand fossiliferous slab which has been assigned to this zone.

The B3 zone in Victoria is marked by the entry of the three-branched form of T. fruticosus, and may be defined as the zone of T. fruticosus 4 br. and 3 br. No sign of its presence in New Zealand has been recorded, a fact which makes it difficult to characterise satisfactorily the lower limit of the succeeding Zone B2.

From a negative standpoint the B2 zone may be defined as the zone of T. fruticosus 3 br. without either T. fruticosus 4 br. or Didymograptus protobifidus. The first absence betokens a disappearance which is far less significant than the second. Positive criteria are not so obvious. There are present in the beds assigned to this zone in New Zealand Goniograptus thureaui, Sigmagraptus laxus, T. fruticosus 3 br. and 2 br., T. harti, T. serra, T. similis, D. extensusnitidus transients, Phyllograptus angustifolius, and P. cf. typus, but these also occur in the B3 zone in Victoria. D. similis, which in Victoria makes its first appearance in the B2 beds, has also been found together with Phyllograptus anna and P. ilicifolius, which have not yet been recorded from that state. The thickness of the beds on Cape Providence which have been assigned to this zone is less than 200ft.

Zone B1 has been defined by the Victorian geologists as that characterised by T. fruticosus 3 br. and Didymograptus “bifidus” [“bifidus” (T. S. Hall non J. Hall), since described as D. protobifidus Elles], but this definition requires discussion. On the view hitherto held in Victoria, the upward limit of T. fruticosus marks

the close of the Bendigonian Series. On theoretical grounds, since an upward limit is indefinite, the horizon of entry of a new and important species should rather be chosen as marking a significant stratigraphical subdivision, and accordingly Dr. Elles (1932) suggested that the entry of the form she later described as D. protobifidus (Elles 1933) should signalize the commencement of the Castlemaine Series. This would result in the transference of all the strata hitherto included in the B1 zone to the base of the Castlemaine Series. There are, however, reasons for the retention of these beds within the Bendigo Series. The Victorian records have not hitherto emphasised the fact that D. protobifidus is present in but small proportion in the fauna of the zone in question, which still remains characterised by a concentration of pendent and reclined tetragraptids and of extensiform Didymograptids (see Table III, p. 263). If, as Dr. Elles has emphasised (1925, 1933), it is not the mere entry of a form that is the factor determining the commencement of a new faunal zone, but its entry in abundance into the fauna, with a consequent significant change in the concentration of the faunal elements, it seems appropriate still to retain the B1 beds in the Bendigonian. The very definite change in faunal concentration which occurs directly above this zone will then form the appropriate criterion for the recognition of the base of the Castlemaine Series.¹

The following table illustrates this contrast qualitatively, exact quantitative statement being precluded by the sporadic development particularly of the horizontal Tetragraptids and Phyllograptids, and the rarity of preservation of the proximal portions of the extensiform Didymograptids and consequent indeterminate character of the majority of these abundant forms. The latter were therefore omitted in calculating the percentage figures hereunder.

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x Almost entirely T. fruticosus.

y T. pendens.

z Almost entirely D. protobifidus.

The beds of the B1 zone have been observed on Cape Providence, where they are about 100ft. thick, and are probably present on the northern coast of Coal Island. The entrants into the fauna at this stage are Goniograptus crinitus, Tetragraptus pygmaeus, T. taraxacum and T. whitelawi, * the declined Didymograptids D. harrisi, D. nicholsoni var. aotea, and var. planus, the more or less horizontal forms D. adamantinus,* D. cf. ellesi, and D. gracilis, and the dependent forms D. artus and D. protobifidus in very small numbers. The forms marked by an asterisk are, however, present in the B2 beds in Victoria. Of the forms ascending from the lower zone, T. fruticosus 3 br. is by far the most abundant. T. harti is relatively more abundant than before, and the reclined Tetragraptids are particularly plentiful. The extensiform Didymograptids have evolved a little beyond the D. nitidus stage towards D. patulus.

The Castlemaine Series. This series comprised those beds in which the Tetragraptids which dominated the Bendigonian have become subordinate to the Didymograptids. The lowest zone (C5) is sharply distinguished from the underlying beds by the expansion of D. protobifidus, which quickly becomes by far the most abundant and characteristic form, while small forms of Isograptus caduceus (var. primula) now form a significant element in the assemblage. In the upper portion of the zone, the expansion of I. caduceus overtakes that of D protobifidus; the latter form then decreases in abundance, and is not known to occur above this zone in either Victoria or New Zealand. D. bidens, which is probably a local product of D. protobifidus, appears in the upper part of the zone. The extensiform Didymograptids are still very abundant and have almost reached the stage of D. patulus. D. affinis, D. mundus, and D. procumbens make their entry into the New Zealand fauna, but the first two of these are present in the B1 beds in Victoria. The horizontal and reclined Tetragraptids, though diminishing, are still abundant, but the dependent forms have greatly decreased, and in particular T. fruticosus has disappeared. The biserial forms are still very scarce. Beds belonging to this zone occur on the northern shore of Coal Island, and the western side of Cape Providence, where they are rather less than two hundred feet thick. The zone is present in the north-western extremity of the South Island of New Zealand (Shakespear 1908, Hall 1915).

The overlying C4 zone is so far known only on the western side of Cape Providence, and the score of forms collected are insufficient to allow of broad generalisation. It appears that D. protobifidus has been replaced by a possibly descendant form, D. dependulus, as in Victoria (Harris and Keble 1932); I. caduceus has increased in relative abundance and in size, the lunata stage being characteristically developed, and Tetragraptus woodi and Diplograptus longicaudatus enter the New Zealand fauna at this stage.

Less than a hundred feet of beds are known to occur in situ above the C5 zone, but on the eastern side of Cape Providence are pebbles containing abundant large Isograptids, I. caduceus var. victoriae and I. hastatus, together with Loganograptus logani, characteristic of the higher Castlemainian C2 or C1 zones of Victoria.

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It seems necessary to recast this as follows, incorporating the additional information now available:—“Polypary tenuous, consisting of two stipes diverging at an angle of °180 from a sicula under 1.0 mm. long, which gives off two thecae that are relatively short compared with those subsequently developed, and constitute the initial thecae of the two primary stipes. In some exceptional polyparies, after twenty or more thecae have been developed bifurcation takes place, giving rise to a stipe of the second order, which so far as has been observed, remains undivided. The subsequent thecae contrast strongly with the initial thecae. They are about 1.8 mm. long (four times their maximum width), about 0.1 mm. wide for half their length, thence expanding to 0.5 mm. by concave curvature of their ventral walls. They overlap 1/5 of their length. Apertural margins straight or slightly concave, subnormal to axis of the thecae. Thecae 7 in 10 mm.”

The generic position of this form calls for discussion. Hall's placing of the form was not without foundation, as Lapworth's original definition of Leptograptus admits of the occurrence of a secondary branch. It reads: “Polypary consisting of two simple slender flexuous monoprionidian branches proceeding in opposite directions from the major extremity of a well-marked persistent central sicula, which is sometimes developed into a third and central branch. Thecae of the form of those of Pleurograptus. Radicle and lateral spines usually invisible.” The thecae of T. S. Hall's form, although exhibiting unusual characters, are not unlike those of Pleurograptus. However, the amended description as given by Elles and Wood under Lapworth's editorship (Mon. Brit. Grapt. Pt. 3, p. 104, 1906), provided for two crossing canals, stipes diverging at angles exceeding 180°, and apertures situated in excavations and slightly introverted—features which exclude T. S. Hall's form from the Leptograptidae. Hall's form has, moreover, three peculiarities. The theeae following the initial ones are markedly more elongate, and overlap only a small fraction of their length. If the dichotomising character did not reassert itself occasionally in the distal thecae, the species might be relegated to the didymograptids. Elles and Wood's (Lapworth's) revised diagnosis of Bryograptus may, however, be wide enough to receive this form. Such species as B. divergens E. and W. and B. lapworthi Rued. exemplify the dormant dichotomising power and its reassertion in distal thecae.

B. antiquus (T. S. Hall) is a fairly common species in the Victorian rocks of the L3 and L2 zones. In our New Zealand area there are a few forms which seem indistinguishable from this species.

Localities: 2 (1), 3 (2); Zone L3.

23, (2); Zone L2 (high).

Bryograptus (?) antiquus var. inusitatus¹ var. nov. (Plate 30, figs. 17, 18).

Holotype: Specimen 468 (6); Paratype: Specimen 468 (5).

Polypary tenuous, consisting of two stipes diverging from a sicula under 1.0 mm. long, which gives off two thecae shorter than the subsequent thecae. These initial thecae give rise to two stipes

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which diverge at 180°. A stipe of the second order may arise from a distal theca. The thecae after the first are set 6–7 in 10 mm.; approximately 0.1 mm. wide for 4/5 of their length, then expanding to 0.5 mm. by a markedly concave curvature of the ventral wall. Apertural margins concave, supernormal to the axis of the thecae, subnormal to that of the branch. Thecae overlap for only a small fraction of their length.

The bifurcation of stipe is exhibited by Specimen 444 of our collection, but in the absence of a sicula, it cannot be seen at what theca the division occurs. This form appears in this highest part of L3 and extends throughout the L2 zone.

Localities: 3 (1), 4 (2); Zone L3 (high).

23 (6), 27 (1 cf); Zone L2.

Associates: B. (?) antiquus, B. clarkei, B. divergens var. subsimus, B. hunnebergensis, B. simplex, Clonograptus tenellus var. kingi, Tetragraptus decipiens.

Bryograptus clarkei T. S. Hall 1898.

B. clarkei T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), 1898, pl. 165, p. 165, pl. 17, fig. 3, 4.

Range in Victoria L3 to L2; a comparable form appears at a higher horizon in New Zealand.

Localities: 3 (6); Zone L3.

22 (2); Zone L2.

24 (2 cf.); Zone B5.

Bryograptus cf. divergens Elles and Wood 1902.

B. divergens Elles and Wood, Mon. Brit. Grapt., pt. 1, 1902, p. 90, pl. 12, fig. 2.

This species was described from a single specimen in Zone 2 of the British sequence. It has not been found in Victoria. Three examples of a comparable form were collected at Cape Providence.

Locality: 15 (3); Zone L2 (low).

Bryograptus divergens var. subsimus¹ var. nov. (Plate 30, fig. 39; Plate 33, fig. 4).

Holotype: Specimen 310 (1).

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Two stipes 0.5 mm. wide diverge at an angle of about 150° from a relatively inconspicuous sicula about 1.3 mm. long, and after three or more thecae have developed, these stipes bifurcate, giving rise to four stipes of the second order. Thecae 10–12 in 10 mm., inclined at an angle of 20°-30°; length about 1.2 mm., three times as long as wide; overlap 1/3 -½; ventral margins straight or slightly concave; apertural margins straight, oblique to the axis of the theca.

Remarks. The relation existing between this form, B. divergens, and B. lapworthi Rued, may be tabulated thus:—

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The angle of divergence of the stipes is much greater in var. subsimus than in B. divergens, but in most other points there is general agreement, and if this apparent angle be of distinctive importance and not due to the mode of preservation, the recognition of a new variety may be justifiable. The thecae are wider and more closely set than those of B. lapworthi, which has about the same angle of divergence as var. subsimus, and, broadly speaking, the bifurcation of the stipes in B. divergens and var. subsimus is relatively proximal, while that of B. lapworthi is relatively distal. The form of the aperture of var. subsimus varies according to the aspect and condition of preservation; it is generally oblique in the reverse aspect, and normal in obverse. Its associates are those enumerated for B. (?) antiquus var. inusitatus.

Localities: 15 (3), 22 (1), 23 (3); Zone L2 (low).

Bryograptus hunnebergensis Moberg 1892 (Plate 30, figs. 1–11, 14, 15).

B. hunnebergensis Moberg, Sveriges Geol. Undersöking., Serie C, No. 125, 1892, p. 92, pl. 2, fig. 5–7.

Westergård, Meddl. Lunds Geol. Faltklubb., Ser. B, No. 4, 1909, p. 64–66, pl. 5, fig. 10–20, 22.

Stubblefield, Geol. Mag., 1929, pp. 273–8, fig. 2.

This form was found by us in considerable abundance and was denoted by us in Part I of these papers under the name of B. pauxillus sp. nov. as a species characteristic of the L2 zone. Dr. Bulman has, however, pointed out to us the difficulty of separating from Moberg's species our rather imperfectly preserved forms. They fail to show any bithecae, but that is also true of the majority of Swedish examples. The form of the polypary, mode of branching, angle of divergence and shape of the thecae in the New Zealand forms agree with those characteristic of B. hunnebergensis, but in some of our specimens the thecae are rather more closely set (14 in 10 mm.) than is typical of this species, and the thecal overlap appears to be rather less. In others of our forms, as shown in the illustrations, agreement with B. hunnebergensis is complete in this respect also. The sicula in our examples is sometimes a little smaller than in the Swedish, though usually about the same size.

This was among the first New Zealand bryograptids to be studied. It was figured without description or determination by the late Dr. T. S. Hall (1915, Figs. 5 and 6) from material derived from the

neighbourhood of the Morning Star Mine, Otago's Retreat (Locality 26). It enters the L3 zone in small numbers, apparently becomes more abundant in its upper portions, and reaches its maximum in the L2 zone. It occurs in the Clonograptus tenellus shales of Sweden, and the higher Tremadoc (Zone 2) beds of Britain.

Localities: 3 (1), 4 (1), 20 (1), 26 (8); Zone L3

15 (12), 19 (10), 22 (28), 23 (4), 27 (12); Zone L2.

Bryograptus cf. lapworthi Ruedemann 1904.

B. lapworthi Ruedemann, Grapt. N. York, pt. 1, 1904, p. 639, pl. 165, fig. 1–18.

This American species occurs in Zone 5a and b, of the Deep Kill section, New York, and has not hitherto been noted in Europe or Australia, though it was recognised by Mrs Shakespear (1908) in material from the Castlemainian beds of North-west Nelson, New Zealand. The forms we here compare with this species come from older formations.

Localities: 3 (2); Zone L3.

6 (1); Zone B5.

Bryograptus simplex Tornquist 1904 (Plate 30, figs. 12, 13).

B. simplex Tornquist, Lunds Univ. Arsskrift, Bd. 40, Afdeln 1, No. 2, 1904, pp. 3–4, pl. 1, fig. 1–4.

We are again indebted to Dr. Bulman for the recognition that certain of our Bryograptids appear to agree with Tornquist's species in all essential particulars, notably the large size, acutely tapering shape, and oblique aperture of the sicula, the habit of branching, and the frequent retention of the didymograptid stage of development. Our figures, however, illustrate an inclination of the thecae rather less than is typical, and consequent smaller width of stipe, but possibly this may be the result of the accident of preservation. B. simplex occurs in the Tetragraptus phyllograptoides zone in Sweden, where it is associated with T. acclinans¹ (?). It occasionally occurs with the latter in the B5 zone in New Zealand, but is more often seen at a lower horizon.

Localities: 19 (3), 21 (1), 22 (2), 23 (4); Zone L2.

6 (2); Zone B5.

Bryograptus victoriae T. S. Hall 1898.

B. victoriae T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), 1898, p. 165, pl. 17, fig. 1, 2.

This form ranges through Zones L3 and L2 in Victoria, and has a similar distribution in New Zealand.

Localities: 3 (3), 20 (1), 26 (5); Zone L3.

15 (2), 22 (2), 27 (10); Zone L2.

Genus Clonograptus Hall and Nicholson 1873.

Clonograptus abnormis (J. Hall) 1857 (Plate 32, fig. 8).

Graptolithus abnormis J. Hall, Rep. Geol. Surv. Canada, 1865, Grapts. Quebec Group, p. 165, pl. 2, fig. 1–5.

Clonograptus abnormis T. S. Hall, Rec. Geol. Surv. Vict., vol. 3, 1912, p. 210, fig. 4.

This species, which occurs in Zone 1 at Quebec (Clark 1924), ranges in Victoria through Zones B1 and C5. Our specimen is from Cape Providence, Locality 8; Zone B1 (low).

Clonograptus flexilis (J. Hall) 1857.

Graptolithus flexilis J. Hall, Rept. Geol. Surv. Canada, 1865, Grapts. Quebec Group, p. 103, pl. 10, fig. 3–9.

Clonograptus flexilis T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), p. 169, pl. 19, fig. 20.

This species, which occurs in the lowest graptolite bed at Port Lévis, Quebec, ranges throughout the Zone L3-L1 in Victoria. Our material contains a poorly preserved sample from the Morning Star Mine, Locality 26, Zone L3 (high) and a larger and better preserved one from Cape Providence, Locality 15, Zone L2 (low).

Clonograptus cf. magnificus Pritchard 1891.

C. magnificus. G. B. Pritchard, Proc. Roy. Soc. Vict., vol. 4 (n.s.), 1891, p. 58, pl. 6, fig. 1–3. Ibid., vol. 8, 1895, p. 29.

This species ranges in Victoria from L3 to B5. Our three examples are from Cape Providence, Locality 2, Zone L3.

Clonograptus rigidus (J. Hall) 1857 (Plate 32, fig. 2).

Graptolithus rigidus J. Hall. Rept. Geol. Surv. Canada, 1865, Grapts. Quebec Group, p. 105, pl. 11, fig. 1.5.

Clonograptus rigidus T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), 1898, p. 170, pl. 19, fig. 21.

This form occurs at the lowest bed at Port Lévis, Quebec, and ranges through Zones L3 and L2, and possibly L1 in Victoria. Our example comes from Cape Providence, Locality 5, Zone L2 (low). A water-worn specimen, possibly comparable with this species, was obtained by Mr J. S. Nicol from Te Oneroa Beach near Locality 26 (? Zone L3 high), and is in the Canterbury Museum.

Clonograptus tenellus (Linnarsson) 1871 (Plate 32, fig. 4).

C. tenellus. Elles and Wood, Mon. Brit. Grapt., pt. 1, 1902, p. 83, pl. 11, fig. 2a-c.

T. S. Hall, Trans. N.Z. Inst., vol. 47, 1915, p. 411, pl. 8, fig. 1–2.

This species is confined to Zone 2 in the British sequence. In Victoria it ranges from L3 to the base of B4. Hall recognised it in a small collection of forms obtained by Mr J. S. Nicol from near the Morning Star Mine near Loc. 26 (L3, high), but our only specimen was derived from Cape Providence, Locality 6, Zone B5.

Clonograptus tenellus var. callavei Lapworth 1880.

C. tenellus var. callavei Elles and Wood, op. cit. supra, p. 84, text-fig. 47, p. 11, fig. 3a-3.

T. S. Hall, op. cit. supra, p. 411, pl. 8, fig. 3.

This form occurs in Zone 2 in the British sequence. It was recognised by Hall, in material collected by Mr J. S. Nicol from the vicinity of the Morning Star Mine (Zone L3, high), but was not obtained by us.

Clonograptus tenellus var. kingi var. nov. (Plate 32, fig. 3-5). Holotype: Specimen 306 (1).

Stipes thread-like about 0.2 mm. wide. Thecae close-set, 17–21 in 10 mm., inclined at about 30°, overlapping ¼; ventral walls concave, apertural margins straight and normal to the axis of the thecae. Sicula about 0.8 mm. long.

Remarks. This form differs from the parent, C. tenellus, in that its thecae are more closely set, the thecal apertures are not

Tetragraptus approximatus Nicholson 1873 (Plate 33, fig. 22).

T. approximatus Nicholson, Ann. Mag. Nat. Hist., ser. 4, vol. 11, p. 136, fig. 2.

(?) Tornquist, Lunds Universitets Arsskrift, Bd. 40, Afdeln 1, No. 2, 1904, p. 6, pl. 1, fig. 11–12.

Keble, Rec. Geol. Sur. Vict., vol. 4, 1920, p. 195, fig. 61, pl. 33, fig. la—c.

This distinctive form, first described from the lowest beds at Port Lévis, Quebec, occurs also on an unknown horizon in Arkansas and perhaps in the T. phyllograptoides beds in Sweden, in which certain of the forms referred to this species by Tornquist appear transitional towards, if not actually referrable to, the form subsequently described by Keble as T. acclinans. The species characterises the L1 and B5 zones of Victoria.

Localities: 6 (4), and 24 (17); Zone B5.

Tetragraptus chapmani Keble and Harris 1934.

T. chapmani Keble and Harris, Mem. Nat. Mus. Melb., No. 8, 1934, p. 169, pl. 22, fig. 3a–b.

This distinctive form occurs in Victoria in Zones L2–B5. Our three specimens are from Locality 24, Zone B5.

Tetragraptus decipiens T. S. Hall 1899.

T. decipiens T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), 1899, p. 168, pl. 17–18.

T. S. Hall, Trans. N.Z. Inst., vol. 47, 1915, p. 410, pl. 8, fig. 7.

Keble, Rec. Geol. Sur. Vict., vol. 4, 1920, p. 200, text-fig. 4, pl. 34.

This form was among the first Lancefieldian graptolites found in New Zealand, being part of a small collection from the Morning Star Mine, Preservation Inlet, described by Hall. It extends in Victoria from the L3 Zone into the B5, and is most abundant in the middle portion of its range. The occurrence in New Zealand is similar.

Localities: 1 (5), 2 (2), 3 (17), 4 (2), 26 (4); Zone L3.

5 (1), 15 (27), 19 (7), 22 (5), 23 (1), 27 (3), 28 (6); Zone L2.

6 (1), 24 (8); Zone B5.

Tetragraptus decipiens var. bipatens Harris and Keble 1934.

T. decipiens var. bipatens Keble and Harris, Mem. Nat. Mus. Melb., No. 8, 1934, p. 170, text-figs. 2–3.

This variety has the same range as the parent species in New Zealand as in Victoria. Our specimens come from: Locality 3 (1); Zone L3. Locality 15 (6); Zone L2 (low). Locality 24 (9); Zone B5.

Tetragraptus fruticosus (J. Hall) 1857 (Plate 30, fig. 41; Plate 33, figs. 25, 27).

T. fruticosus Elles and Wood, Mon. Brit. Grapt., Part. I, 1902, p. 61, text-fig. 37, pl. 6, fig. 2a, b.

Ruedemann, Grapt. N. York, Part I, 1904, p. 649, pl. 9, fig. 11–14, pl. 10.

Harris and Keble, Proc. Roy. Soc. Vict., vol. 44, 1932, p. 35, pl. 4, fig. 1, 5.

This species is characteristic of the Bendigonian rocks in Australia as in New Zealand, and was the first graptolite to be specifically recognised in the latter country (in Nelson Province).¹ In the B5

zone it is usually represented by small four-branched forms, in which the stipes are often widely spread and rarely more than 15 mm. long. The mature, larger and pendant habit was developed a little later. The three-branched forms appear first in the B3 zone in Victoria. In the higher zones, B2 and B1, the species is much more abundant, the stipes reach a length of 35 mm., bending outwards about 20–30 mm. from the sicula. In these zones only three-branched or occasionally two-branched forms are present.

Localities: Four-branched forms:

6 (3), 24 (17); Zone B5.

Three-branched forms:

7 (12), 29 (4), 30 (9); Zone B2.

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8 (10), 9 (55), 13/14 (12); Zone B1.

Two-branched forms:

7 (2); Zone B2. 9 (1); Zone B1.

Tetragraptus fruticosus var. conferticosus var. nov. (Plate 33, figs. 23, 24, 28).

Holotype: Specimen 169 (1).

This variety differs from the parent species in (a) the closer setting of the thecae, which number 9 or 10 in 10 mm. in place of the normal 6–8; (b) the ventral margins are more nearly straight, producing rather more acute denticles with the apertural margins; and (c) the increase in width of the stipe is more gradual. Our specimens do not display the proximal region clearly, and the details of the initial thecae are obscure. The holotype suggests an unsymmetrical distribution of the stipes, which is, however, probably the result of distortion. In this specimen the width of the stipe is 0-4–0-5 mm. near the sicula, but increases to about 1–5 mm. near the ninth thecae, beyond which further increase is scarcely perceptible. Our three specimens are from Locality 24, Zone B5.

Associates: T. acclinans, T. approximatus, T. decipiens, T. postlethwaitei, T. quadribrachiatus.

Tetragraptus harti T. S. Hall 1914 (Plate 33, figs. 2, 3;? fig. 10).

T. harti T. S. Hall, Proc. Roy. Soc. Vict., vol. 27 (n.s.), p. 113, text-figs. 5 and 6.

This form, which differs from T. quadribrachiatus chiefly in the narrowness of the stipe, ranges in Victoria from Zone B3 to C3. Our forms occur thus: Localities 7 (1), Zone B2; 8 (8), 9 (1), Zone B1; 32 (2), Zone C5. What may be a variety of this species or of T. quadribrachiatus is illustrated by Plate 33, fig. 10. It occurs with T. pendens and D. protobifidus in a pebble (Specimen 1455) found by Mr Charles Yunge on Cape Providence. The thecae in this form appear more closely set than those of T. harti, and of rather different form, but the fossil is too distorted to admit of description.

Tetragraptus pendens Elles 1898 (Plate 33, fig. 26).

T. pendens Elles and Wood, Mon. Brit. Grapt., Part 1, 1902, p. 61. pl. 6. fig. 2a–b.

Ruedemann, Grapt. N. York, Part 1, 1904, p. 653, pl. 11, fig. 17–20.

This species ranges through Zones 5 and 6 in Great Britain, Sub-zones C2-D1 (of Clark 1924) in Quebec, and Sub-zone 6a in New York. It appears to have entered at little earlier into the

Victorian sequence, where it ranges from L1 to C4. Our forms occur in Localities 24 (1 cf.), Zone B5; 7 (1), 30 (1), Zone B2; and 8 (3), Zone B1; in association with T. cf. harti, and D. protobifidus in the above-mentioned pebble from Cape Providence probably derived from the C5 zone; perhaps also in Professor Park's collection from the upper portion of the C5 beds of Cape Providence (3).

Tetragraptus cf. postlethwaitei Elles 1898 (Plate 30, fig. 40; Plate 31, fig. 15; Plate 33, figs. 14, 15).

T. postlethwaitei Elles and Wood, Mon. Brit. Grapt., Part 1, p. 64, pl. 6, fig. 1.

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Our form consists of four stipes over 17 mm. long, which in the uncompressed condition were probably symmetrically declined, but which, perhaps because of the stoutness of the sicula, have usually been twisted on compression so that the outer stipes may be in a slightly reclined position. In regard to the dimensions and form of the sicula, the maximum width of the stipe, and the spacing, inclination, dimensions, form, and overlap of the thecae, our forms are inseparable from T. postlethwaitei. The width of the stipe increases from 0–9 mm. at the sicula to 1–6 mm. by the twelfth theca, beyond which it remains constant. Elles and Wood cite uniformity of width as a feature distinguishing T. postlethwaitei from other declined forms, but their figure seems to show some widening, though uniformity commences at an earlier stage than in our form. In view of the fact that their diagnosis was based on a much smaller number of forms than are in our collection, it seems better to extend the limit of variability of the species to include our specimens, than to erect a new variety. T. postlethwaitei, according to information kindly given by Dr Elles, occurs in the Skiddaw District near the base of Zone 4 or just below it, horizons closely comparable with those occupied by our specimens which were found at Locality 15/16 (2), Zone L2 (low), and Locality 24 (33), Zone B5.

Tetragraptus pygmaeus Ruedemann 1904 (Plate 30, fig. 16).

T. pygmaeus Ruedemann, Grapt. N. York, Part 1, 1904, p. 664, pl. 12, fig. 11–14.

This species is unrecorded in Britain, and has not hitherto been found in the Australasian region. It occurs in Zones 5 and 6 in New York State. Our single specimen was found at Locality 13, Zone B1.

Tetragraptus quadribrachiatus J. Hall 1857 (Plate 33, figs. 5, 6, 21).

T. quadribrachiatus Elles and Wood, Mon. Brit. Grapt., Part 1, 1902, p. 57, pl. 5, fig. la-d.

Ruedemann, Grapt. N. York, Part 2, 1904, p. 645, pl. 11, fig. 1–4.

This cosmopolitan form extends in Britain through Zones 3, 4 (maximum) and 5, in New York State through Zones 2 (maximum) to 4a, and in Victoria from Middle Lancefieldian L3 to the close of the Darriwillian with a strongly marked maximum in the Lower Bendigonian. The range in New Zealand appears to be similar. About a quarter of the forms occurring in the horizon of maximum concentration, the B5 zone, have thecae slightly more closely spaced than is normal, 10–12 in 10 mm. in place of 8–10, and consequently

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a rather greater overlap, ½–1/3 in place of ¼, also slightly smaller inclination 25°–35° in place of 30°–40°. These forms are illustrated by figs. 5 and 6 of Plate 33, but seem better considered as the extreme of a variable species, rather than a distinct variety.

Localities: 5 (3); Zone L2. 6 (1), 24 (85); Zone B5.

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30 (1); Zone B2. 9 (5), 13/14 (1); Zone B1.

Park's collection, Cape Providence (2); Zone C5 (high).

12 (2); Zone C4.

Tetragraptus serra (Brongn.) 1828, emend. Elles and Wood 1902.

T. serra Elles and Wood, Mon. Brit. Grapt., Part 1, 1902, p. 65, pl. 6, fig. 4a-f.

Ruedemann, Grapt. N. York, Part 1, 1904, p. 653, pl. 11, fig. 8–10.

For the reason indicated when discussing T. amii, it would appear that Victorian geologists were strictly correct in utilising the name T. bryonoides J. Hall for some at least of the forms now referred to this species, but also that Lapworth's usage of the name has now become established as the general practice. The range of this cosmopolitan form is through Zones 4 (maximum) and 5 in Britain; it is rare in Zone 1, abundant in Zone 2, and extends with modification to Zone 5 in New York State; in Victoria it appears in Zone B4, and is abundant in the higher Bendigo and the Castlemaine beds, and extends to the upper Darriwillian (D2).

Localities: 7 (3), 29 (4), 30 (3); Zone B2.

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8 (6), 9 (19), 13/14 (4), 31 (1); Zone B1.

10a (1), 32 (21); Zone C5.

Park's collection, C. Providence (13); Zone C5 (high).

Tetragraptus similis (J. Hall) 1857 (Plate 30, fig. 19).

T. bigsbyi Elles and Wood, Mon. Brit. Grapt., Part 1, 1902, p. 68, pl. 6, fig. 6a-c.

T. similis Ruedemann, Grapt. N. York, Part 1, 1904, p. 658, pl. 11, fig. 2–10.

There appears to be no general consensus as to the correct name for this cosmopolitan form. Because of the greater similarity of the New Zealand faunal assemblage to the Victorian than to any other, we have here followed the Victorian usage, though it might have been preferable to adopt the British. The form ranges through Zones 4 and 5 in Britain, is abundant in Subzone 5b and rare in 6a in New York State, and in Victoria extends from Zone B4 to the top of the Castlemaine beds. It has been found in abundance in North-west Nelson (Shakespear, 1908), in beds probably referable to C5 (Hall, 1915), but in our collections it has been derived from nearly as wide a range of beds as in Victoria.

Localities: 7 (6), 29 (1), 30 (3); Zone B2.

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8 (3), 9 (4), 13/14 (4); Zone B1.

10 (4), 10a (1), 32 (22); Zone C5.

11 (4), Park's collection, C. Providence (6); Zone C5 (high).

12 (4); Zone C4.

Though these have more affinities with D. artus than with any other described species, some of the features of D. murchisoni var. geminus are suggested. D. artus has not yet been recognised in Australasia; it occurs in Zone 6 in Great Britain. Our specimens were derived as follows:—

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Localities: 8 (1), 13/14 (1); Zone B1. 10 (2); Zone C5.

Didymograptus cf. aureus T. S. Hall 1914.

D. aureus T. S. Hall, Proc. Roy. Soc. Vict., vol. 27 (n.s.), 1914, p. 105, pl. 17, fig. 4.

This form ranges in Victoria from Zone L1 into B5. Our two examples which were found in situ were derived from Locality 24, Zone B5. The presence of this form was also noted in a provisional study of a pebble obtained near Locality 6 on Cape Providence, in which it was associated with T. fruticosus 4 br. and Goniograptus macer, but the material was mislaid before critical examination was possible. It was probably derived from Zone B4.

Didymograptus bartrumi sp. nov. (Plate 31, fig. 19).

Holotype: Specimen 52.

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Stipes diverge at an angle of 140° from a stout sicula 2.0 mm. or more in length and furnished with a nema. At their origin they are 0.8 mm. wide, but expand to over 2.0 mm. at their distal ends. In length they reach 24 mm. or more. Thecae are from 13 to 15 in 10 mm.; relatively narrow tubes four or five times as long as wide and overlapping 2/3-¾ of their length; ventral margins straight, inclination 45°; apertural margins straight or slightly concave and rather oblique.

Remarks. Out of the many thousands of specimens of Victorian didymograptids examined by one of us (Keble) none appears to be exactly similar to this form. Its closest ally among the declined forms is perhaps D. simulans, but many points of distinction therefrom may be detected. Some forms that have been referred to D. nitidus are also rather like D. bartrumi, but the general robustness of the polypary as well as other features serve to distinguish the latter form. Our single specimen comes from Locality 24, Zone B5.

Associates: T. acclinans, T. approximatus, T. decipiens, T. fruticosus 4 br., T. postlethwaitei, and rarely D. extensus.

Didymograptus bidens Keble 1927.

D. bidens Keble, Trans. N.Z. Inst., vol. 58, 1927, p. 157, fig. 1, 2.

This species was originally described from Professor Park's collection from the Upper C5 beds on Cape Providence. We have since obtained an additional example from Locality 11, which is closely adjacent to Prof. Park's locality, and about the same horizon.

Didymograptus dependulus Harris and Keble 1932 (Plate 31, fig. 16).

D. dependulus Harris and Keble, Proc. Roy. Soc. Vict., vol. 44 (n.s.), 1932, p. 46, pl. 6, fig. 1–2.

This form is characteristic of the C4 Zone in Victoria. Our single specimen agrees with the Victorian form in all essential features, save that the thecae (12 in 10 mm.) are rather more closely set than is normal (10–11 in 10 mm.).

Locality 12; Zone C4.

Didymograptus cf. ellesi Ruedemann 1902 (Plate 31, fig. 14).

D. ellesi Ruedemann, Grapt. N. York, Part 1, 1904, p. 682, text-figs. 75–76, pl. 14, fig. 22–24.

This form is here recorded for the first time in Australasia. It occurs in Sub-zone 6a in New York State.

Localities: 9 (1); Zone B1. 11 (1); Zone C5 (high).

Didymograptus eocaduceus Harris 1933 (Plate 30, fig. 20).

D. eocaduceus Harris, Proc. Roy. Soc. Vict., vol. 46 (n.s.), 1933, p. 109, pl. 6, fig. 8a-b.

This form, which resembles certain aspects of T. similis, has been recently described by Harris from the Lower Bendigonian zones of Victoria. Our examples come from rather lower beds.

Localities: 19 (2), 22 (1); Zone L2.

Didymograptus cf. euodus Lapworth 1875

D. euodus Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 21, pl. 1, fig. 10a-b.

This species occurs in Zone 7 of the British sequence, and an allied form occurs throughout the Darriwil beds of Victoria and the base of the Upper Ordovician (Cobb Beds) of Nelson Province (Keble and Benson, 1929). It is, therefore, unlikely that the single specimen derived from the C5 beds at Locality 32 should belong to this species, though (perhaps as a result of the accident of preservation) it resembles D. euodus more closely than it does any other known form.

Didymograptus extensus Series.

D. extensus-hirundo series, Elles, Summ. Prog. Geol. Sur. Grt. Britain for 1932, Part II, 1933, pp. 99, 111, figs. 6–12.

D. extensus (Hall) Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 8, pl. 1, fig. 1a-b.

Elles, Op. cit. supra, 1933, p. 111, fig. 7; non Tornquist, Lunds Universitets Arsskrift, Bd. 37, Afdeln 2, No. 5, 1901, p. 14–15, pl. 1, fig. 25–30 (an extensus-nitidus transient, fide Dr Elles).

D. nitidus (Hall) Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 10, pl. 1, fig. 2a-c.

Elles, Op. cit. supra, 1933, p. 111, fig. 8.

D. patulus (Hall pars) Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 13, pl. 1, fig. 8a-c.

Elles, Op. cit. supra, 1933, p. 111, f. 9; non Tornquist, Lunds Universitets Arsskrift, Bd. 37, Afdeln 2, No. 5, 1901, p. 15–17, pl. 2, fig. 1–6.

Dr. Elles (1933) has shown that the three species noted above are the early members of an evolving series of extensiform graptolites, appearing in regular sequence, and connected by many intermediate or transient forms. In Britain the series commences with relatively few and small forms in the lowest sub-zone (a) of Zone 4 (the D. extensus zone). The typical D. extensus occurs abundantly in sub-zone (b) associated with transients towards D. nitidus. D. nitidus s. str., with early nitidus-hirundo transients (D. patulus) appear in association with D. protobfidus and a few small forms of Isograptus gibberulus (caduceus) in sub-zone (c). In the highest sub-zone (d), later nitidus-hirundo transients, D. patulus, D. suecicus and D. praenuntius occur with large and abundant forms of I. caduceus. In Victoria D. extensus and allied forms extend from B3 to C4, and are most abundant in the higher Bendigonian zones. A form referred perhaps erroneously to D. nitidus has been recorded in B4, and the

species extends up to C2. It has also been recognised in C5 and C1 beds in Nelson, New Zealand (Shakespear 1908, Hall, 1915). D. patulus has not hitherto been recognised in Australasia. The members of this series present in our collections have not yet been critically studied in regard to their evolutionary stages, and we are indebted to Dr. Elles for placing those which we have illustrated. They are distributed as follows:—

D. extensus and closely allied extensus-nitidus transients (Plate 30, fig. 26, Plate 31, figs. 2, 6, and (?) 7 = D. extensus s. str. Plate 31, figs. 8, 9 = D. extensus-nitidus).

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Localities: 6 (4), 24 (2); Zone B5. 7 (5), 29 (1); Zone B2. 8 (2), 9 (9), 13/14 (6); Zone B1. 32 (2); Zone C5 (low). Prof. Park's collection, Cape Providence (6); Zone C5 (high).

D. nitidus s. str. and closely allied transients (Plate 31, fig. 3 = D. nitidus s. str. Fig. 1 = an early nitidus-patulus transient).

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Localities: 7 (7); Zone B2. 8 (5), 13/14 (5), 31 (2); Zone B1. 32 (3); Zone C5 (low). 11 (1); Zone C5 (high).

D. patulus-nitidus (not quite D. patulus s. str.) (Plate 31, fig. 4).

Locality: 11 (1); Zone C5 (high).

Didymograptus gracilis Tornquist 1891.

D. gracilis Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 24, pl. 2, fig. 2.

Ruedemann, Grapt. N. York, Part 1, 1904, p. 679, pl. 14, fig. 15–21; non McCoy, Prod. Pal. Vict., Dec. 2, 1875, p. 35.

This species ranges in Britain through Zones 4–6, occurs in Sub-zone 6a in New York State, and extends from Zone B3 to D4 in Victoria. Our two specimens are from Locality 8 (1?), Zone B1, and 32 (1), Zone C5.

Didymograptus harrisi sp. nov. (Plate 31, fig. 21).

Holotype: Specimen 831.

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The polypary is contained within angle of 120°. The stipes are 0.5 mm. wide at the sicula, and rapidly attain a width of 0.8 mm., which is maintained thereafter. The greatest stipe in our single specimen is 22 mm. long. The sicula is slightly more than 1.0 mm. long and relatively broad. Thecae 8 in 10 mm.; distal thecae uniformly 0.75 mm. wide, three times as long as wide, ventral margins slightly concave, inclined at 20°; apertural margins straight and normal to the axis of the stipe; overlap 1/3.

Remarks. The origin of the first theca is in the apertural half of the sicula and is suggestive of Bryograptus (?) antiquus. The species is distinguished from D. nicholsoni by the wider spacing of the thecae, and in particular from D. nicholsoni var. aotea by the absence of denticulate apertural margins and the slight concavity of the ventral margins. Stipes referrable to D. harrisi have often been noted by one of us (Keble) in Victorian beds on a rather higher horizon than that containing our form. Though a single specimen only is available, it appears worthy of specific recognition

We have pleasure in naming it in honour of our friend Dr. W. J. Harris of Victoria. It was obtained from Locality 8, Zone B1.

Associates: T. amii, T. harti, T. serra, T. similis, D. extensus, D. nitidus, and D. protobifidus.

Didymograptus latus T. S. Hall 1907 (Plate 30, fig. 31).

D. latus T. S. Hall, Rec. Geol. Sur. Vict., vol. 2, 1907, p. 141, pl. 15, fig. 7,

This form occurs in Zone B5 and perhaps the higher part of L1 in Victoria. Our two specimens are from Localities 6 and 24, Zone B5.

Didymograptus mundus T. S. Hall 1914 (Plate 31, fig. 22).

D. mundus T. S. Hall, Proc. Roy. Soc. Vict., vol. 27 (n.s.), 1914, p. 107, pl. 17, fig. 9.

This form, which is very closely allied to D. nitidus, ranges in Victoria from Zone B1 to C2. Our three specimens were obtained on Coal Island at Locality 32, Zone C5.

Didymograptus nicholsoni Lapw. var. aotea¹ var. nov. (Plate 30, fig. 35; Plate 31, fig. 17).

Holotype: Specimen 837 (1).

Two stipes diverge with a proximal angle of 150°, but, after the development of two or three thecae, assume a less open position so that the polypary is enclosed within angle of 110°. Stipes rapidly attain their characteristic width of 1.0 mm., and may be 36 mm. or more long. Sicula less than 2.0 mm. long. Thecae conspicuously denticulate; ventral margins strongly concave; apertural margins straight or slightly concave, generally normal to the axis of the stipe at the proximal end and to that of the thecae at the distal portions; overlap about ½; two or three times as long as wide, inclined at 30°-40°; 11–13 thecae in 10 mm.

Remarks. The sicula unfortunately is obscured by the stipe of another form, but is apparently about 1.5 mm. long, and certainly less than 2.0 mm. The holotype is not well preserved, but the essential characters are visible. The origin of the first theca seems more apical than suboral, and is probably similar to that of D. superstes, the figure of which given by Elles and Wood (Mon. Brit. Grapt., Part 1, 1901, Plate 1, fig. 9a) bears a distinct resemblance to our form, though there are many points of difference. The distal thecae are not unlike those of D. serratulus J. Hall, but again there are distinctive features. The stipes are a little wider and the inclination of the thecae a little greater, and their setting a little closer than that of D. nicholsoni, with which we have tentatively associated this form. It is noteworthy that nothing similar to this has been noticed among the thousands of stipes examined by one of us (Keble) from the Bendigonian beds of Victoria. Our specimen is from Locality 8, Cape Providence, Zone B1 (low).

Didymograptus nicholsoni var. planus Elles and Wood 1901 (Plate 31, fig. 20).

D. nicholsoni var. planus Elles and Wood, Mon. Brit. Grapt., Part 1, 1901, p. 29, pl. 2, fig. 5a-b.

This species, which occurs in Zone 5 of Great Britain, and Sub-zone 5b of New York State, has not hitherto been recognised in Australasia. Our specimen is from Cape Providence, Locality 8, Zone B1.

Didymograptus pritchardi T. S. Hall 1898.

D. pritchardi T. S. Hall, Proc. Roy. Soc. Vict., vol. 11 (n.s.), 1898, p. 167, pl. 17, fig. 7, 9; pl. 19, fig. 8–10.

This species ranges in Victoria through Zones L3 and L2. Our specimen is from Locality 27 on the eastern shore of Otago's Retreat, Zone L2?.

Text-Figure 3.—Didymograptus protobifidus Elles X 2.
a. Small early form. Specimen 255, Locality 10, Cape Providence; lower part of the C5 zone.
b. Specimen 753, Locality 32, Coal Island. Typical of the larger forms in the C5 zone.

Didymograptus protobifidus Elles 1933 (text-figure 3).

D. nanus Lapw. Elles and Wood (pars), Mon. Brit. Grapt., Part 1, 1901, p. 47, pl. 4, fig. 5d, non figs. 5a, b, c, e, g.

D. bifidus T. S. Hall non J. Hall, T. S. Hall, Proc. Roy. Soc. Vict., vol. 27, 1914, p. 108, pl. 17, fig. 11.

D. protobifidus Elles, Summary Progress Geol. Sur. Grt. Brit. for 1932, Part 2, 1933, pp. 98, 110, fig. 1–3.

The form termed D. “bifidus” or “D. bifidus (sensu latu)” in the first part of this series of papers must be referred to the new species instituted by Dr. Elles. It is identical with that formerly described by Victorian geologists as D. bifidus, and with that occurring in North-west Nelson which was referred by Dr. Shakespear (1908) to D. nanus, and by Dr. Hall to D. bifidus (1915). We are greatly indebted to Dr. Elles for examining not only all our bifid forms from Fiordland, but also the material from Nelson which had been studied by Dr. Shakespear. The identity of these forms with D. protobifidus is clear in every case. Since D. bifidus (J. Hall) s. str. and D. nanus Lapw. s. str. are in England associated with a distinctly later assemblage of species than those accompanying the Australasian bifid form, there has been a difficulty in correlation between Britain and Australasia (Harris and Keble, 1932) which has been removed by the identification of the Australasian form with D. protobifidus. The transition towards D. bifidus s. str. shown by increasing thecal overlap and width of stipes is never far advanced among our forms.