TRIGONIA TATEI Neumayr.

1867. Trigonia cassiope R. Tate, Quart. Journ. Geol. Soc., vol. xxiii., p. 158.

1881. Trigonia tatei M. Neumayr, in E. Holub and M. Neumayr, Denkschr. d. k. Akad. Wiss., Math.-Nat. Cl., Band xliv.,

p. 275, pl. ii., fig. 3.

Occurrence.-A very imperfect and ill-preserved fragment of a costate Trigonia occurs in hard limestone with Pleuromya baini from Grass Ridge, three miles east-north-east of Uitenhage (335). In all probability this represents T. tatei.

Remarks.-Although no complete or satisfactorily determinable specimens of this well-characterised form are included in the collection under examination, it may be useful to draw attention to one or two points of interest in reference to the occurrence of this shell, the only member of the section Costatæ hitherto found in the Uitenhage beds. In 1877, Lycett cast doubt upon the correctness of Tate's identification of this South African form with the European Oolitic shells named T. cassiope by d'Orbigny, and Neumayr subsequently saw the necessity of applying a new name. T. tatei certainly cannot be united with any other known costate form, and although the general outline and nature of the ribbed flank has a close parallel in several familiar European Costatæ, yet the narrow area and elongated escutcheon, the delicate and little-prominent carinæ and inter-carinal ridges, and the relatively very delicate beaded ornamentation of area and escutcheon, are very distinctive features.

Two specimens preserved in the collection of the Geological Society of London are labelled "Zwartkop River" (H. Longlands) and "McLoughlin's Rest" (Major Rocke) respectively, and the former specimen appears to have been the one upon which Tate's identification was based. The length is relatively great compared with the height; the cardinal margin is elongated, while the siphonal margin is short. The area is slightly convex in form, without a marked median carina or groove; the escutcheon is large, and ornamented by raised lines of granules running parallel to the ridges of the area. There are about 18 ribs on the flank of the larger specimen. The elongated form, the very delicate carinæ, the fine intercarinal sculpture, the convex area, and the elongated granular escutcheon, are all characters which at once recall the

* Lycett (3), p. 172.

† d'Orbigny (4), vol i., p. 308.

same features in T. tenuis, from the Oomia beds in Cutch.*

This, however, is strongly distinguished from T. tatei by the very crowded and delicate costate ornamentation of the flank, and by the slight convexity of the valve.

In view of the comparative rarity of the Costatæ in the Cretaceous rocks, the occurrence of so typical a member of the section in the Uitenhage Series might appear at first sight to lend some support to the view of those who have maintained that a part, at least, of these beds must be ascribed to the Upper Jurassic. It is clear, however, that in any attempt to uphold such a conclusion, less weight can now be attached to the presence of Costata than when our knowledge of the distribution of this division of the Trigonie was founded principally upon European occurrences. In Europe itself, representatives of the section are sparsely present in the Cretaceous, and these mostly show deviations which at once distinguish them from the typical Jurassic forms. Trigonia peninsularis Coquand, from the Aptian of Spain, exhibits a marked degeneration of characters in its later growth-stages, while T. carinata Agassiz,‡ from the Neocomian and Aptian, which may be brought into the most intimate connection with the Costatæ, shows equally farreaching modifications, although an examination of Lycett's figured specimens and other well-preserved individuals fails to reveal any characters which can be taken to justify Lycett's separation of this form under a separate sectional heading.§ The typical features of the section Costatæ are exemplified, however, in a small Trigonia described by E. Ascher from the Hauterivian of Silesia.||

Although these European forms may be looked upon as lingering representatives of a section which had passed its maximum development, we must look further afield in order to complete the history of this strongly characterised and long-lived division of the genus. In the marine Oomia beds of Cutch, which may now be regarded as of Lower Cretaceous rather than of Upper Jurassic age, aberrant derivatives of the Costatæ provide a striking feature in the molluscan fauna; but here also have been found two representatives, T. tenuis Kitchin and T. parva Kitchin, which retain in perfect manner the typical characters of the section. South America has also furnished another unmodified Cretaceous costate form in T. anguste-costata, described by Behrendsen from strata which he regards as Upper

* Kitchin (1), p. 35, pl. iii., figs. 5, 6.

+ Coquand (1), p. 129, pl. xxiii., fig. 3. Agassiz (1), p. 43, Tab. vii., figs. 7-10; Lycett (3), p. 179, pl. xxxv., figs 3-6, (1877). § See also Collot(1).

|| Ascher (1), p. 159 [25], pl. xiii. [ii.], fig. 10. ¶ Behrendsen (1), p. 6, pl. 3, fig. 7.

Cretaceous, at Caryilauhue (Argentine); this is accompanied by a typical member of the Cretaceous section Scabræ, T. transatlantica Behr. T. anguste-costata is a small triangular shell, which in the delicate character and close spacing of the flank-ribs recalls the Indian T. parva Kitchin, from which, however, it is widely distinguished by the very different outline and the delicate ornamentation of the area. In the perfect development of these longitudinal ridges of the area, T. anguste-costata retains in typical manner an essential feature of the section, a differentiation of the valvesculpture which so strongly and constantly characterises all the Costatæ. With reference to the occurrence of the costate Trigonie in Cretaceous rocks, Behrendsen cites, in addition to T. peninsularis Coquand and T. carinata Agass., the following shells: T. longa Ag., T. pennata Sow., T. cardissa Ag., and T. indica Stoliczka. This list, however, is misleading, as may be ascertained from a careful examination of these forms. T. longa and T. pennata certainly cannot be included in the section Costatæ, while it is doubtful whether T. indica stands in very close connection with this division. T. cardissa, on the other hand, is a typical representative of the section, but it has been shown to be Jurassic, and not Cretaceous,

as at first suggested on insufficient grounds by Agassiz.

GENUS CARDITA J. G. Bruguière.

CARDITA NUCULOIDES Tate.

Plate VII., figs. 5, 5a, 5b.

1867. Cardita nuculoides R. Tate, Quart. Journ. Geol. Soc., vol. xxiii., p. 162, pl. vii., figs. 7a-7d.

Occurrence. Tate's figured specimen, numbered 11028 in the collection of the Geological Society, came from the Sunday's River. A specimen obtained by Mr. Rogers is from the left side of the Coega Valley, half a mile down from the railway (466g).

Remarks. The specimen found by Mr. Rogers is a well-preserved left valve which differs slightly in outline from Tate's figured type: it is a little more drawn out obliquely, and the convex fold of the valve which runs obliquely from the umbonal region to the posteroventral corner is rather more pronounced than in the original type. Tate's specimen, however, although having both valves in place, is not so perfectly preserved, and some allowance may also be made for individual variation. The general form of the shell,

and the complete agreement in the sculpture, leave no doubt that the specimen from Coega Valley must be identified with C. nuculoides.

The form of the shell is that of a four-sided figure with rounded angles. The anterior margin is short, the posterior margin, on the other hand, very extensive. The umbonal region is relatively weakly developed. The surface is beautifully ornamented by numerous, minute, radial striæ which cannot be seen with the naked eye. The intercrossing of the stria with concentric growthlines results in a delicate cancellation.

GENUS ASTARTE J. Sowerby.

ASTARTE LONGLANDSIANA Tate.

1867. Astarte longlandsiana R. Tate, Quart. Journ. Geol. Soc., vol. xxiii., p. 158, pl. viii., figs. 5a, 5b.

Occurrence. Specimens in the collection of the Geological Society are from the Zwartkop's River. Mr. Rogers obtained an immature example of this form in the Coega Valley east of the railway, one mile up the line from Coega station (477g).

Remarks.--The immature specimen from the Coega Valley measures only 19 mm. in height. It has both valves in position, and the umbonal region of the right valve is perfectly preserved. The umbo is acutely pointed and is ornamented by closely spaced concentric ribs up to the apex. Tate says that the valves are ornamented with "slightly elevated ridges of growth," but it would be more correct to say that the ornamentation consists of well-raised concentric ribs. The ribs show some little irregularity of spacing. The surface between the rib-summits frequently shows finer concentric lines, which appear here and there to have the regularity of definite sculpture, though in places they resemble ordinary ridges of growth. The escutcheon is narrow, steep-sided, and deeply excavated, and the ribs of the flank terminate abruptly at the acute margin which bounds the escutcheon.

SUB-GENUS ERIPHYLA F. Stoliczka (? W. M. Gabb).

ASTARTE (ERIPHYLA) HERZOGI (Goldfuss).

1810. Cytherea herzogii (Hausmann) A. Goldfuss, Petrefacta Germaniæ, Band ii., Lief. 7, p. 239, Tab. cxlix., fig. 10.

1843. Astarte capensis F. Krauss, Amtlicher Bericht über die zwanzigste Versammlung der Gesellsch. deutsch. Naturforscher und Aerzte zu Mainz im Sept., 1842, p. 130.

1850. Astarte herzogii F. Krauss, Nov. Act. Acad. Cæs. Leop.-Carol. Nat. Cur., vol. xxii., pt. 2, p. 447, Tab. 47, figs. 2a-2e. 1905. Astarte herzogi A. W. Rogers, An Introduction to the Geology of Cape Colony, p. 291, fig. 25 (1).

Occurrence. Specimens before me are from the uppermost red bed in a kloof east-north-east of Red House on Zwartkop's River (326, 327), and from a krantz near Picnic Bush, north-east of Red House (328). Messrs. Rogers and Schwarz also found this shell in the cutting on the road running from the farm Perseverance on to the plateau, and leading to the Salt Pan. Stow obtained specimens at McLoughlin's Bluff and between the Addo and Modder Drifts, on the Sunday's River. Hertzog's collection, including this shell, was obtained in the Sunday's River district about eighteen. miles from Enon. Krauss collected specimens on the left bank of the Zwartkop's River, below Uitenhage.

Remarks.-Krauss furnished such an accurate description of this shell that it will only be necessary to supplement this by a discussion of its narrower relationships. Astarte herzogi cannot be looked upon as a typical representative of its genus, and it is by no means a simple matter to assign it to its correct position among recognised sub-generic groups. The principal characters to be borne in mind. in this connection are as follows. The shell has a lenticular form and frequently an almost circular outline; it is ornamented by crowded concentric ribs and sulcations forming a well-developed sculpture. The lunule is short, but is sharply bounded and of very deep and concave form; the escutcheon is very narrow and elongated, almost entirely occupied by the long ligament space, and very sharply marked off from the flank. In the right valve there is a distinctly developed posterior lateral dental process, situated behind the elongated external ligament, and an anterior (sub-lunular) depression in the hinge-plate for the reception of an anterior lateral process of the left valve. The pallial margin of the valve is strongly notched on its inner side; the pallial line is posteriorly rather weakly impressed.

We are therefore dealing with an Astarte in which lateral hinge processes are definitely developed. The evidence for the presence or

* See Hausmann (1), p. 1459 (as Cytherea).