ment, were nevertheless peculiarly local in their occurrence, even within a relatively restricted area. The greater, then, is the necessity for caution in generalising from scanty data regarding the insufficiently explored littoral Neocomian deposits with which we are dealing.

V. DESCRIPTIONS, CRITICAL NOTES, AND LISTS OF FOSSILS.

In the records of occurrence accompanying the following descriptions, it will be understood that when no collector's name is mentioned, and no other indications are given, the specimens in question were obtained by Mr. A. W. Rogers and Mr. E. H. L. Schwarz in 1900 or by Mr. Rogers in 1905. The numbers quoted in parentheses refer to numbers printed on labels affixed to the specimens. All the specimens obtained in 1900 by Messrs. Rogers and Schwarz, and some also sent to me from the collection in the South African Museum, are labelled with plain numbers printed on yellow paper. Those collected in 1905 by Mr. Rogers have blue labels bearing a number followed by an alphabetical letter. A few of the specimens from the South African Museum and all those comprising the collection obtained by Miss M. Wilman at Coega are without numbers.

With the exception of Holcostephanus baini, H. modderensis, and H. wilmanæ, all the fossils fully dealt with in these pages are represented in the collections submitted to me by Mr. Rogers; but it need scarcely be remarked that these only include examples of about twothirds of the species of invertebrates known to occur in the Uitenhage Series, and it may be added that the published accounts of several types figured or described by Sharpe and Tate call for critical revision at some future time. To deal exhaustively with all the invertebrate forms hitherto recorded from the Uitenhage beds is beyond the scope of this memoir; and since a single compiled list of the whole fauna, including names taken without criticism from other works, would be open to obvious objection, it will be found that lists of species with localities given at the close of this descriptive section, contain names which, except those of the ammonites just mentioned, refer only to specimens entrusted to me by Mr. Rogers. Additional notes of occurrences, however, frequently accompany the following descriptions and comparisons, and are based on specimens preserved in the collection of the Geological Society of London or in the British Museum (Natural History). A few forms not dealt with

in detail below have already been briefly noticed in the second section of this paper, in so far as it seemed necessary to draw attention to their significance in reference to the question of geological age: the names of these, and the remainder of the invertebrate fossils of the Uitenhage Series which have hitherto been recorded, are brought together in the supplementary list and brief accompanying notes with which the present section of this memoir concludes.

In those few instances in which Uitenhage forms are referred to European species, I have refrained from burdening the subjoined accounts with full synonymic lists, but have given a reference to the original description and, where possible, to a recent work in which fuller guidance to the literature of the species may be obtained. Throughout the following pages, however, nomenclatural references are restricted to those works which contain such information as to insure, in my belief, the truly synonymic value of the citations.

In the description of the Gasteropoda a conventional orientation is employed for the sake of clearness, and when use is made of the terms "above" and "below" in this connection it is assumed that the specimen be held with the apex directed vertically upwards. The terms "nepionic" and "neanic," occasionally employed with reference to the young or immature stages in some of the lamellibranchs described below, are so well known and so frequently used as to call for no explanation here.*

For an account of the available geological information in connection with the occurrence of the specimens obtained in 1900 reference should of course be made to the Report by Messrs. Rogers and Schwarz, but this may be supplemented by a brief note contained in a letter written to me by Mr. Rogers, to the following effect: "The specimens from Dunbrodie and Blue Cliff are from the lower beds of the Uitenhage Series, those from the Clay Pit near Rawson Bridge from the lowest marine beds in the Zwartkop's River section. Those from the Grass Ridge, Uitenhage, and from the kloofs near Red House and Picnic Bush belong to the highest beds we found, and the specimens from the Graaff-Reinet railway section and those from the main line up-side of Rawson Bridge are from the middle portion of the marine beds." I am informed that the collection obtained at Coega by Miss Wilman was made at a locality on the farm of that name, though outside the river valley, while the label "Coega River" refers to a section in the river valley on the same farm, but probably on a rather lower horizon in the Marine Beds. * See Hyatt (1); Jackson (1), p. 293; Buckman and Bather (1); Hyatt (2), p. 94. Rogers and Schwarz (1); also Rogers (1), pp. 281–292.

In the case of the specimens from the collection of the South African Museum labelled " Sunday's River," no more detailed account of locality is available, but these are all typical Mollusca of the Marine Beds or Sunday's River Beds. Of all the fossils examined, the only forms which indicate fresh-water conditions are the Unio from the Wood Beds of the Bezuidenhouts River, below Blue Cliff station, and a single specimen of Limnæa from the section at Buck Kraal, Sunday's River. Whatever may be the exact relation of the fossiliferous beds exposed below Dunbrodie (occurring below a band containing plant impressions) to the main part of the "Wood Bed" series, the fauna from Dunbrodie is essentially a marine one: as already stated in the second section of this paper, there is no reason on palæontological grounds to suppose that this small marine assemblage, characterised by the prevalence of Gasteropoda, is materially older than the fauna yielded by the Trigonia-bearing Marine Beds.

The collection obtained by Mr. Rogers from the Marine Beds of the Coega River and Sunday's River valleys, in 1905, includes some interesting additions to the fauna. For full information concerning the occurrence of these and commoner associated forms, the recent report by Mr. Rogers should be consulted.* This work adds materially to our knowledge of the Sunday's River Beds, particularly with regard to the vertical distribution of many of the Mollusca in the extensive sections examined; but the results in no way strengthen the hope that a scheme of zonal subdivision of the Marine Beds may soon be within reach of attainment. On the contrary, the evidence obtained by Mr. Rogers, as already mentioned, seems to emphasise the striking similarity in the aspect of the fauna throughout the whole thickness of beds exposed.

The few specimens found by Mr. Rogers in a patch of marine Uitenhage beds at Knysna Estuary only represent the product of a hasty search, and it is believed that careful collecting at this new locality may yield good results.

CLASS ANTHOZOA.

GENUS THAMNASTRÆEA Lesauvage.

THAMNASTRÆA sp.

There are several specimens of a Thamnastrea from the locality between milestones 24 and 24 on the railway between Uitenhage

*

Rogers (2), pp. 22-33.

Schwarz (2), pp. 50, 74.

For remarks on the correct application of this generic name see Gregory (2),

p. 131.

and Graaff-Reinet (345-349). These occur in a hard limestone matrix, and the coral itself is replaced by crystalline carbonate of lime and is in a condition unfavourable for detailed study. The corallum is relatively slender, subcylindrical and branching in form. The calicinal centres are situated at about 2 mm. from one another.

Prof. J. W. Gregory has seen a specimen of this form, and considers that it may be correctly assigned to the genus Thamnas træa. In view of the scanty material so far obtained, and its imperfect condition, a fuller description and comparison with described species may be deferred for the present.

CLASS ANNELIDA.

GENUS SERPULA Linnæus.

SERPULA cf. CONCAVA (J. Sowerby).

Plate II., figs. 1, 1a.

Cf. 1814. Vermicularia concava J. Sowerby, The Mineral Conchology of Great Britain, vol. i., p. 125, Tab. 57, figs. 1–5.

,, 1836. Vermetus concavus J. de C. Sowerby, Trans. Geol. Soc. Lond., ser. 2, vol. iv., p. 343, pl. xviii., fig. 10. 1884. Vermicularia concava R. Damon, Geology of Weymouth, Portland and Coast of Dorsetshire, 2nd edition, p. 128, fig. 48.

Description. The tube is wound in the form of a very flat spire, widely umbilicated, with the apical part not projecting above the outside whorl when viewed in lateral profile. The whorls are in close contact, or slightly embracing. The tube is of slightly flattened cylindrical or oval section, the flattening at right angles to the axis of the spire. After the third whorl the tube ceases to be coiled and becomes free. The surface of the tube is marked by numerous irregular transverse wrinkles and furrows.

241-24 on the railway between Uitenhage and Graaff-Reinet (332), in the railway cutting.

Remarks.-The specimen described in all probability has not attained its full growth, and the manner in which the tube for about the last 2 mm. of its length has grown free from the coil suggests that we have only the commencement of an uncoiled stage illustrated in this individual. The subsequent growth of the tube was probably in a more or less nearly straight line as in Serpula concava, and it is impossible to say what dimensions the detached portion of the tube might attain.

In general aspect this Serpula very closely resembles S. concava (Sow.) (Upper Greensand), and agrees in the dimensions of the coiled stage, but without a sufficient number of specimens for critical comparison nothing further can be said regarding its actual affinities. A similar form from the Neocomian of France was figured by Leymerie as Serpula lituola. In the general habit and mode of growth there is also resemblance to S. damesi Noetling, † from the Cenomanian boulders of North Germany, but the African form differs in the smaller number of whorls, the smaller dimensions, and the thinner walls of the tube.

SERPULA PINCHINIANA Tate.

1867. Serpula (Vermilia) pinchiniana R. Tate, Quart. Journ. Geol. Soc., vol. xxiii., p. 163, pl. ix., figs. 10a-c.

The large cylindrical tubes of this form are sometimes seen attached to massive lamellibranch-shells such as Exogyra imbricata Krauss, or one of the pseudo-quadrate Trigonia. The adherent stage is irregular in the direction of its growth: it sometimes follows a sinuous course, and in some cases the tube is bent sharply back upon its path and grows over itself. The generally smooth surface of the tube is occasionally marked by irregular annular thickenings.

Mr. Rogers collected specimens from the Cliff on Buck Kraal, Sunday's River, attached to Trigonia herzogi (122h), and at the left side of the Coega Valley, half a mile down from the railway (458g, on Trigonia holubi). Another example is attached to a valve of Exogyra imbricata from the Sunday's River (303), belonging to the collection of the South African Museum.

* Leymerie (3), pl. 6, fig. 5.

↑ Noetling (1), p. 10 [206], Taf. i., figs. 8-10.