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).

The collection of Fossil Vertebrata in the National Museum at Washington is at present insignificant; and the only type-specimens observed by the writer are the fish-remains described by Prof. Leidy under the names of Clupea humilis, Cladocyclus occidentalis, Phareodus acutus, and Lepidosteus simplex, besides some fragmentary specimens from the Hamilton Group made known by Prof. J. M. Clarke in the Bull. U. S. Geol. Survey, No. 16 (1885). The palæontologist interested in the lower vertebrates, however, finds much to occupy him in the collection of recent fish skeletons made by Prof. Theodore Gill, who has contributed perhaps more than any other ichthyologist to our knowledge of those parts with which the palæontologist is alone able to deal. At the time of the writer's visit, Prof. Gill was occupied with an investigation of the skeletal anatomy of the eels; and a large number of beautiful drawings of the cranial osteology of various great groups of bony fishes, as yet in the Professor's portfolio, are intended for the basis of a forthcoming general work, to which all who are interested in palajichthyology will anxiously look forward.

Of late years the Cambrian Conglomerates have received a considerable amount of attention, as it has been shown that much information concerning the nature and condition of the Pre-Cambrian rocks can be obtained by the careful examination of the materials composing the conglomerates in different areas. It is evident that rocks similar to the rolled fragments in the Conglomerates must have been present in pre-Cambrian times to yield these fragments, and if in certain areas special rocks occur abundantly or otherwise, the characters of the pre-Cambrian rocks in these areas may be to a great extent determined. The Cambrian Conglomerates in Wales and Shropshire have been very carefully examined by Prof. Hughes, Dr. Callaway, and myself, and the materials collected have been submitted to Prof. Bonney and Mr. T. Davies for microscopical examination.

Mr. R. Storms has recently described (Bull. Soc. Beige Géol. vol. iii. p. 163, 1889) the vertebras of a large Tunny from the Antwerp Crag, which he has named Thynnus Scaldesii, and Mr. A. Smith Woodward, in the April number of the Annals and Magazine of Natural History, records the same species from the Coralline Crag of Suffolk; it is especially interesting, therefore, to be able at this time to notice the occurrence of the common Tunny (T. thynnus) in the Crotner “Forest Bed.”

During the past summer I had the pleasure of studying the Miocene and Upper Oligocene beds at various places in the Bordelais, mostly under the guidance of the amiable Professor of Geology in the Faculté des Sciences in Bordeaux, Monsieur E. Fallot; and the following notes are mainly intended to give an idea of the present appearance of the classical Miocene sections in that district, and to say something concerning their classification and that of the other Tertiary beds of the Gironde, following the most recent researches on the subject.

Fossil Mammalian remains from Olivola were already known in the last century. Giovanni Targioni Tozzetti describes and figures several bones from that locality, which he refers to some species of Tricliechus or Phoca, but which, as far as the figures permit of a judgment, belonged to Ruminants. In this century, the deposit was mentioned by Pareto, and by Cocchi, who from stratigraphical considerations ascribe it to the Pleistocene.

Now that so close attention is being given to the microscopic investigation of rock structures, it is somewhat remarkable that no one should yet have questioned the validity of the views currently received regarding the exact constitution of limestone. Taking account only of those limestones whose original structure has not been obliterated by subsequent changes, the general view isthat nearly the whole mass, in the great majority of cases, is either directly, or indirectly, due to organic agencies. This view is even maintained in the cases where a microscopic examination of the rock fails to reveal more than a few traces of any structure that can be regarded as organic.

Of “those precious specimens called ‘types’ which must be appealed to through all time to determine the species to which a name was originally given,”Bristol Museum contains one hundred and eighty six distinct fossil forms. With the exception of a single Coal-measure plant, these are all the remains of animals, ranging in the zoological scale from the Reptiiia to the Actinozoa, and stratigraphically from the Silurian to the Cretaceous epochs.

The proofs of a much greater elevation of the American continent at no very distant geological date, which have been communicated to the Geol. Mag. by Prof. J. W. Spencer and Mr. W. Upham, are very interesting, and Mr. Upham's suggestion that this great elevation occurred in Pliocene and early Pleistocene time is a taking one. He thinks the culmination of the uplift coincided with the Glacial period, and was to a large extent the cause of that period; if he is right, we are forced to infer that there has been a post-Glacial submergence to the extent of over 3000 feet over the whole region, including the Gulf of Mexico. There is, however, a difficulty in this supposition, to which I beg to call Mr. Upham's attention.

My paper on the Culm-measures at Bude has elicited two communications, from Messrs W. Maynard Hutchings and Alfred Harker, on which I desire to offer a few comments.

I take this opportunity of saying that I am extremely glad to find that the conclusion at which I arrived regarding the impotence of pressure alone to produce metamorphism is in accord with the published views of my friend Mr. J. J. Harris Teall. “Pressure” alone, he states, in a footnote at p. 410 of his valuable work, British Petrography, “produces no effects on rocks—work must be done upon rocks before change takes place.” This footnote escaped my memory at the time of writing my paper, or I should have called attention to it.

I cannot conclude this paper without remarking that none of the views therein are held dogmatically, and expressing the hope that former observers will renew their attention, and fresh ones take up the investigation of this complicated, yet interesting area. The difficulties are great, among which is the origin of the banded structure, in the rocks herein dealt with, which in my next paper I shall try to explain on the grounds of segregation, arising from, or taking place during the cooling of the common magma out of which all these rocks seem to me to have been formed.

As Dr. Callaway has asked in a recent Number of the Geological Magazine for the grounds on which I suggest that some of the volcanic rocks of Shropshire may perhaps be classed as Cambrian, I take this opportunity for bringing before your readers the present state of the inquiry into the nature and classification of the earliest sedimentary rocks in this country. This inquiry has been spoken of by Dr. Callaway as the “Archæan controversy”; but we must not necessarily call everything that is earlier than the Cambrian “Archasan,” any more than in old days it was right to call everything Precarboniferous “unfossiliferous greywacké”; nor should the inquiry be considered a controversy in its present stage, but rather a search for more accurate knowledge.

The interesting phenomenon exhibited in some glassy rocks, such as obsidians and pitchstones, known as the perlitic structure, consists of a series of rectilinear and curved cracks. It has been produced artificially in Canada Balsam, and described by Mr. Grenville A. J. Cole, F.G.S.

Hitherto, any attempts of mine to produce the curved or secondary cracks on a glass plate were unsuccessful (the only result being primary cracks and appearances of air films between the glass and balsam); until noticing their occurrence on a rough mounting plate, it became evident that a roughened glass surface was the requisite thing in order to secure perfect cohesion. It is probable, therefore, that the specimen which Mr. Cole produced occurred on a ground portion of the glass plate.

Mr. Sorby, in his Address as President of the Eoyal Microscopical Society in 1877, dwelt very forcibly on the interest and value attaching to researches into the original nature of the materials composing sedimentary deposits, and stated that, so far as he was aware, but little had been done in this direction by means of the microscope (Monthly Microscop. Journal, vol. xvii.).

Crystallized silicate of zinc, Willemite, has frequently been observed, artificially formed, in metallurgical operations, but so far as I am aware no case has been recorded of its crystallizing out from a magma of slag of a different composition, of which the zinc silicate formed only a comparatively small proportion.

In Davidson's Monograph of the British Carboniferous Brachiopoda (1857), p. 60, he gives the following specific characters of Spirifera glabra:—“Very variable in shape and proportions; transversely oval, rarely as long or longer than wide. Valves almost equally convex, with a mesial elevation or fold in the dorsal, and a sinus in the ventral valve. Hinge-line much shorter than the greatest width of the shell; cardinal angles rounded; beaks rather approximate, that of the larger or ventral valve prominent, incurved, and of moderate dimensions. A hinge-area in the dorsal valve, that of the ventral one triangular and of moderate dimensions, with its lateral margins more or less sharply defined; fissure partially covered by a pseudo-deltidium. The mesial fold in the dorsal valve is either slightly and evenly convex, rising gradually from the lateral portions of the valve, or abruptly elevated, with a longitudinal depression along its middle, which is also at times reproduced in the sinus of the ventral one. The spiral appendages are large, and occupy the greater portion of the interior of the shell. Surface of valves in general smooth, but sometimes a few obscure rounded ribs may be observed on their lateral portions”