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Volume 56, 1926
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– 307 –

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.

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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).

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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.

(a.)

Lorne. Matrix of green foraminiferal calcareous clay:—

5.

Corbula canalicvlata = Eucrassatella sp., probably E. media n. sp. Fragmentary cast. The curvature of the beaks shows that we are dealing with a left valve, which in C. canaliculata is almost smooth, not ribbed as this shell is.
6.

Corbula sp. = Fossularca januaria n. sp. The matrix had not been cleared away from the hinge, and the back of the shell certainly looked like a Corbula.
7.

Crassatellites obesus = Eucrassatella media.
10.

Cymatium minimum = Austrotriton n. sp. Spire not so high as minimum, and only about half the number of ribs of A. maorium Finlay.
13.

Fusinus solidus = Fusinus n. sp. Closely related, but with 8 axial ribs instead of 12. Most of the specimen is an internal cast, so it is too poor for specific description. Another specimen of different matrix (b) was with this one.
14.

Glycymeris globosa = Glycymeris lornensis Marwick.
18.

Mitra inconspicua = Vexillum lornense n. sp. There are only 3 plaits on the columella, and the surface has obsolete cancellate sculpture. M. inconspicua is smooth and has 4 columellar plaits.
20.

Ostrea subdentata = Ostrea n. sp. cf. mackayi Suter, but of more irregular growth and thicker.
23.

Protocardia pulchella = Nemocardium semitectum n. sp.
26.

Serpulorbis sipho = Siliquaria senex n. sp.
32.

Turritella carlottae = T. lornensis n. sp.
34.

Venericardia difficilis benhami = Venericardia benhami (Thomson).
35.

Venericardia sp. = V. benhami. One specimen of a different species is set in matrix C.
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(b.)

Whitish calcareous matrix, sometimes richly foraminiferal, sometimes with considerable tufaceous matter (perhaps from more than one locality):—

1.

Cantharidus fenestratus = indeterminable. The specimen is a distorted internal cast, so it is difficult, if not impossible, to make certain of its relationship.
2.

Capulus sp. = an internal cast of a shell much more coiled than Capulus australis. It might be from a high-beaked Venericardia.
4.

Cardium sp. = Venericardia sp. A small shell of 10 mm. diameter with about 20 ribs.
12.

Daphnella sp. = Acamptochetus n. sp. Two distorted whorls only.
13.

Fusinus solidus = internal cast with smooth whorls, so not solidus.
15.

Hemiconus ornatus = internal cast of Conospira sp. Indeterminable.
16.

Leda semiteres = Nuculana sp. A small shell, 5 mm. long, closed and damaged.
17.

Lima paleata = Lima paleata.
19.

Mytilus huttoni = Lima? Distorted cast of closed individual; 21–25 strong ribs with equal interstices.
22.

Pleurotomaria tertiaria = internal cast of a shell, 40 mm. in diameter, 35 mm. high. May be a Pleurotomaria, but no sign of slit.
24.

Protocardia sera = Venericardia casts, strongly asymmetrical and incurved.
27.

Siphonalia conoidea = Aethocola sp. A fragment with 15 ribs on body, and strong spiral cords with wide interstices containing weak secondaries.
(c.)

Coarse whitish-brown sandstone (? locality):—

28.

Struthiolaria cincta = Monalaria concinna (Suter). The specimen is almost wholly a cast, but the characteristic winged aperture is plainly seen.
29.

Struthiolaria minor = Monalaria concinna (juvenile).
35.

Venericardia sp. = a small Venericardia of 8 mm. diameter; number of ribs uncertain, but apparently less than 20.
(d.)

Dark-brown rusty sandstone, probably from vicinity of Windsor or Tapui:—
3.

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).
9.

Cylichnella enysi = Bulinella n. sp. Casts not so cylindrical as enysi.
11.

Cytherea sp. ? = Eucrassatella sp. of quite characteristic shape.
21.

Panope orbita = Panope worthingtoni. Longer and more regular than P. orbita.
25.

Psammobia lineolata = a cast showing part of hinge of an equilateral shell with long well-developed laterals; probably Mactra.
29.

Struthiolaria minor = Monalaria concinna (juvenile).
30.

Struthiolaria tuberculata concinna = Monalaria concinna.
31.

Tellina eugonia? = Tellina n. sp. 25 mm. by 16 mm. Beaks only 11 mm. from posterior end; posterior dorsal margin well curved.
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(e.)

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.

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