GENTLEMEN, In conformity with your expressed wish, I forward to you the accompanying drawing (Pl. XVII) of the fossils from Snowdon and its vicinity; and shall now proceed to offer you my opinion, or rather my conjectures, upon the nature of each one in particular, first observing that scarcely any of them possess sufficient character to enable me to-speak with any tolerable degree of certainty. Several of them must remain undecided, until more perfect specimens can be obtained; because they are destitute of those parts from which generic characters are taken. Almost all the organic remains to be traced in these specimens appear to me to be bivalve and principally terebratuloid shells. The specimen numbered 1 and 2 in the drawing appears to be a cast of the inside of the deep valve of a Productus,* of which fig. 1 shows the back, and fig. 2, the hinge: it has distinct but rather flat ribs, and it is compressed in a direction from the back to the hinge. Fig. 3 is a view of another specimen, which I believe to be the same species, but which is compressed laterally, so that the ribs are much more prominent. Figs. 4 and 5 are two views of an entirely detached little cast which is rather concave on one side, and convex on the other. I think this may decidedly be referred to the genus, if indeed it be a distinct genus, described under the name of hysterolites, which we are informed in the Dictionnaire des Sciences Naturelles are only found in the oldest beds. As a species, it differs from the only one I had before seen in having distinct longitudinal diverging ribs. Fig. 6 is a representation of a fossil which I thought at first was probably the flat valve of a productus; but judging from its principal features, I am now rather disposed to think it may also be an hysterolite. It is a very flat impression, and it has two sets of diverging ribs, only distinct towards the margin, one set smaller than the other, and interposed between the larger. The fragments represented in fig. Il appear to me to belong to the same; they are compressed in various directions. There is another impression upon the same stone as fig. 6. I have numbered it 7, and I cannot help expressing some doubt about the real nature of this impression; if it be that of a shell, it is certainly an impression of the outside of an avicula. Fig. 8 is probably the impression of the outside of the opposite valve of the same kind of shell as fig. 6. The fossil represented at fig. 9 is, perhaps, the most singular of all; it appears to be a cast of the inside of a terebratuloid shell, and like many of them it has several strong diverging ribs, most prominent towards the * I make use of this name because it is at present generally adopted. I am perfectly aware of the impropriety of using a Latin adjective as a generic appellation, and am consequently happy to learn from a gentleman who has lately taken much trouble in investigating these fossils, that the use of this appellation will be superseded, and a name which has the right of priority, adopted in its stead. In using the term Productus, I do not venture an opinion upon the real nature of these fossils. margin; but it is principally remarkable for a strongly prominent three-sided projection, something like an irregular, ill-shaped tetrahedron, one point of whose base is exactly at the point of the umbo of the hinge, and the two others are directed towards the two corresponding sides of the margin. I strongly suspect that this projection has been rendered unnaturally prominent by being rather laterally compressed. Fig. 10 is an indistinct fragment of the impression, probably of the lower valve of an hysterolite. Fig. 12, a bit of slate, which contains some pyrites, and upon which is an impression very much like that of the scale of the cone of some species of pinus; but it is quite impossible for me to decide whether it is an animal or vegetable remain. Fig. 13 has the appearance of the outside of a bivalve shell, but it is extremely indistinct, and I dare not venture a conjecture upon it. Fig. 14, part of an impression of the outside of one valve of a bivalve shell, but to what genus it is referrible, I do not know; probably a Venus or a cytherea. Fig. 15, a very indistinct section of a madrepore. I am, Gentlemen, yours, &c. G. B. SOWERBY, ARTICLE II. On the Ultimate Analysis of Vegetable and Animal Substances. By W. Prout, MD. FRS. (To the Editor of the Annals of Philosophy.) DEAR SIR, Southampton-street, Nov. 15, 1822. In the second part of the Phil. Trans. for the present year, just published, there is a paper by Dr. Ure on the Ultimate Analysis of Vegetable and Animal Substances. In this paper, Dr. Ure states that he has constantly found about three per cent. more of carbon in sugar than what I obtained, and that the results of his analysis of urea differ very considerably from M. Berard's and mine, especially in the proportion of azote. The chief object of this notice is to endeavour to throw some light on these differences; and first with respect to sugar. Dr. Ure states that he employed the best refined sugar of commerce. I used fectly white and pure crystallized sugar-candy, under the imperpression that this would be more likely to be fixed and definite in its composition, than the imperfectly crystallized sugar in common use, I have indeed, with other views, once or twice operated on common sugar, but without much attention to accuracy; so that I cannot with certainty state whether coincide with those of Dr. Ure. With respect to urea, what I my results employed was perfectly pure, in which state it exists as a beau tifully white crystallized substance (very like oxalic acid in appearance), permanent in ordinary states of the atmosphere, and without any remarkable taste or smell. I may remark, that the above two substances were among the first I analysed, and that the analyses were made with a charcoal apparatus much less capable of precision than the lamp apparatus which I subsequently employed. The views which I published some years ago respecting the atomic theory, seem to be now generally known in this country. These views at the time led me to others which I was exceedingly anxious to verify; and as I was interested, for other reasons, in the composition of organic substances, it struck me that by submitting these substances to analysis, I might not only obtain a knowledge of their composition, but by investigating the laws which might regulate the union of their elements, hydrogen, carbon, oxygen, and azote, be able to obtain an insight into the laws which regulate the union of other elementary principles. With these views, therefore, I set to work, and after very great labour, and no trifling expence in apparatus, &c. succeeded, as I supposed, in analyzing more or less perfectly almost every well-defined and crystallized organic substance that I could procure. A few of my earlier results were published, perhaps, prematurely, but the great mass, as is well known to several of my friends, still remains by me, nor have I, for various reasons, the least inclination to publish them at present. In the mean time, however, it may be stated, that the substances analyzed were dried at 212° in vacuo with sulphuric acid, by means of an apparatus described by me several years ago for that purpose, that every precaution (including those mentioned by Dr. Ure as well as others), were taken to insure accuracy, that, with the exception of sugar, and one or two other substances, every substance analyzed by Dr. Ure and myself in common appears by the charcoal apparatus to contain less carbon than by the lamp apparatus.* I am, dear Sir, yours, &c. WILLIAM PROUT. * In making this remark, I by no means wish to insinuate that Dr. Ure's results are erroneous; my object is merely to show that the lamp apparatus is as capable in many instances of oxidizing carbon as the charcoal apparatus. It is probable that several of the substances examined by Dr. Ure could only be analyzed by some such means as those he employed; but for the analysis of most substances containing azote, I do not hesitate to say that I prefer the lamp apparatus. ARTICLE III. Remarks on the Geology of Lindisfarn, or Holy Island. By N.J. Winch, Esq. Honorary Member of the Geological Society of London, and of the Mineralogical Society of Dresden. With a Plate. (No. XVIII.) (To the Editor of the Annals of Philosophy.) SIR, Newcastle-upon-Tyne, Nov. 1, 1822. PREVIOUSLY to attempting a description of the geological structure of Lindisfarn, it may not be amiss to mention a few leading particulars respecting the island, which will at least save the trouble of referring to printed authorities on the subject. The venerable Bede, who wrote in the eighth century, calls Lindisfarn a semiisland, being surrounded by the sea twice every 24 hours; and a popular poet of the present day delineates this striking phenomenon in the following lines: "The tide did now its flood-mark gain, Of staves and sandal'd feet the trace." Ages have passed away since the time of Bede, and but little alteration seems to have taken place during the long interval, either on the western side of Holy Island, or on the opposite coast of Northumberland-a clear proof of the sea having made no considerable inroads for centuries on the indented shore of this part of England, and warranting the supposition that the Farn islands and Staples must have been divided from the main land by the agency of a temporary current of water sufficiently strong to break up and remove the adjoining strata of limestone, shale, and sandstone, but not powerful enough to destroy the more obdurate masses of basalt which have been thus left in their present isolated situations. The length of the island from north to south including a peninsula called the Snook, is about two miles and three quarters; its breadth from east to west, a mile and a half. The town contains about 500 inhabitants, of whom 70 are fishermen, usually engaged in the white-fish or herring fisheries, but acting occasionally as pilots, many of them being legally authorized by the Trinity House at Newcastle. The harbour is extensive and safe, except during heavy gales of wind from the westward; it has eight feet water on the bar at low water, and twenty-two 1 |