This species is represented by one cast and part of another, in red sandstone from Bucks Co., Pennsylvania, given to me not long before his death by my lamented friend, Professor Henry Carvill Lewis, F.G.S., etc., of Philadelphia.

In the Palæontology of the Vertebrata, so much has been accomplished on the American Continent within recent years, that any European interested in this line of research is naturally attracted to the Museums and collections across the Atlantic. Among others, the writer of the present notes has at various times been desirous of comparing certain American and Canadian discoveries with those now familiar to workers in the Old World; and this desire having lately been gratified, it may not be uninteresting to offer a few remarks on the collections of extinct Vertebrata in the New World, viewed from the standpoint of one who has had the privilege of visiting many of the corresponding collections in Europe.

It is I think, practically admitted that the present condition of the Weald is the result, firstly of marine, and secondly of subaerial denudation. A plain of marine denudation was first formed, and the valleys were carved out by subaerial action.

As a basis for the following observations on the classification of Tertiary and Post-tertiary strata, we submit a comparative view of the nomenclature adopted by various authors.

In a characteristic article by Prof. Blake, “On the Base of the Sedimentary Series in England and Wales,” in the July Number of the Geological Magazine, amongst other erroneous statements, there is one which I must beg leave to correct. At page 310, in referring to the rocks of St. Davids, he makes the following statement: “While accepting the later petrological descriptions of Dr. Hicks, he (Dr. Geikie) minimized the separation between this [the Pebidian] and the Cambrian conglomerate, and challenged Dr. Hicks to prove his statement that the latter is chiefly composed of fragments of the rock on which it lies. This Dr. Hicks has never been able to do, seeing that the most marked feature of the conglomerate is that it is not composed of such fragments; instead of doing so, he now attempts to show that the matrix might have been derived from granitoid rocks.”

In the “Palæontologia Indica,” ser. 10, vol. ii. p. 349, fig. 21, I described and figured a lower premolar from the Siwaliks of the Punjab, under the name of Hyænodon indius; the figure being reproduced in the accompanying woodcut (Fig. 1).

Few students of Geology can doubt that the elevation of the Weald has been the most important factor concerned in determining the present surface-geology of the south-east of England. It has been constantly before my own mind in all my studies of Tertiary Geology for the last ten years, as the problem to the solution of which many other preliminary questions required answers. In my first paper on Tertiary Geology, read before the Geologists' Association in 1883, I pointed out that the presence of Eocene pebble-beds in the Woolwich and Reading series and in the Bagshot series afforded strong evidence of the encroachment of the sea upon the Upper Chalk in Eocene times. This conclusion is accepted by our greatest authority on Tertiary Geology, Prof. Prestwicb. The fact alone furnishes a strong presumption that the elevation of the Weald had commenced before the close of the Eocene period; while the many outliers of the Woolwich and Reading beds at high altitudes on the N. Downs, taken along with the general absence of the London Clay there, seems to tell us that the initial elevation of the Weald hill-range had gone far enough for this to form a shore to the area of deposition of the London Clay. I have shown further, in a former volume of the Geol. Mag., that, though there is no absolute proof, there are grounds for believing, that certain outliers of sands on the N. Downs (at Chipstead, Headley, and north of Netley Heath) are more likely to turn out to be of Upper Eocene age, than of any age to which they had been hitherto assigned by different writers.

Amongst the specimens sent many years ago, from South Africa, by the late Mr. Andrew Geddes Bain, to the Geological Society of London, are two small blocks of greenish-grey hard mudstone or shale, very slightly calcareons; one bed-plane in each, specimen bears upon its surface numerous valves of one or more forms of small Lamellibranchs, closely resembling the shells of the genera Cyrena and Cyclas in contour.

There is some doubt as to this being the type. The specimen in the Bristol Museum so referred is stated to have come from “Warminster,” but Sowerby gives “Blackdown” as the locality of his type. The specimen in this Museum agrees very well with Sowerby's figure, and also with Davidson's reproduction of the same (fig. 31, supra), but not with fig. 32, the specimen stated by him to be in the Bristol Museum.