I Have not hitherto seen any specimen so Satisfactorily and finely illustrative of the affinity of Strophodus to Cestracion as that figured in Plate VII. and which is now in the British Museum. It consists of the major part of the dental covering of a jaw, including the posterior part of the symphysis, and shows that the principal or largest, as in Cestracion. These are followed by two rows (at least) of smaller crushing teeth, and are preceded by rows of teeth both smaller and more produced at the middle of their working surface, and in the same degree changing from the crushing molar to the conical prehensile type. This dental coating or armature is imbedded in a block of the fine Oolitic building-stone from Caen, which has taken the place of the dissolved cartilaginous support of the teeth, so as to maintain and exhibit the curve of the arch (fig.1a) by which the teeth obliquely overspanned the jaw to which they were originaly attached.

It is now generally recognised that the power which forces up lava from a depth of miles through narrow and crooked fissures broken across the solid crust of the globe, is no other than steam, developed in the interior of the lava by vaporisation of water intimately disseminated throughout its substance. I am not aware that previously to the publication of my volume on Volcanos in 1825. But I had derived a conviction of 1822, and a study of Etna and Stromboli in the years 1819–21. This was subsequently confirmed by the discoveries of Sorby, Scheerer, and others, of the existence of water in intimate molecular combination with the crystalline or granular minerals that compose the granitic rocks from the fusion of which lava is supposed to proceed. I had expressed my belief that the aqueous particles so confined, whether in a liquid or a solid state, would upon the occurence of increased heat, or diminished pressure, exert an elastic separating force upon the solid crystals of granules, in the manner of a flux, and thus assist the liquefaction of the mass, and drive it up any fissure that might open for its passage, in a pasty or semi-liquid state, short of complete fusion; so that on reaching the outer air, and parting with the contained steam, together with the heat which the expansion of this element would carry off in a latent from, its surface would consolidate instantly; and the solidification extending rapidly inwards by the formation of crevices giving an outlet to further vapour, the resulting rock would exhibit a cellular or porous structure, and a granular or crystalline texture, in lieu of the compact and glassy one which, if completely fused, it should possess.

Having in my last communication presented the most recent views entertained by M. Coquand, I now proceed to mention those held by Monsieur Hébert, a most experienced observer, who has made the “Cretaceous system” a subject of particulat study. M. Hébert considers that M. Coquand has sepatated the period into too many definite divisions (étages), and in two papers published in the Bullettin of the Geological Society of France (Vol. 16 and 20, 2nd series), his views upon that topic have been fully recorded. He had not, however, drawn up any complete scheme of classification, but this he has now kindly done at my request. (See Table of Classification.)

The existence of Post-pliocene deposits in this neighbourhood has until lately been quite unknown, nothing of the kind having been detected either by the Geological Survey or subsequent observers. However, in tlie winter of 1866, a small section was exposed in a brick-field situated on a low rising-ground at the first milestone out of Shaftesbtiry towards Gillingham, and known as Hawkers' Hill. The clay here dug for brickmaking is Kimmeridge, presenting fossilized bones of the Pliosaurus and Icthyosaurus, and very friable remains of an Ammonite, etc. The attention of the writer was first attracted to the Drift on observing, above part of the Kimmeridge clay, a thin section of soil of an ochreous tint due to oxide of iron, and somewhat resembling the loose stratum of chert and sand which caps the neighbouring Green-sand rock. He learnt on inquiring of the labourers that they had recently found some large bones in this deposit, but thinking them of no use they had wheeled them off with the rubbish, in which they then lay, efiectually re-buried. Much interested at this announcement, he induced the men again to remove the rubbish, and found that the bones were some vertebræ of a large mammalian animal, together with fragments of the ribs and leg-bones. They were, of course, not at all fossilized, and their original weak state had been sadly aggravated by a second burial and disinterment. Nothing more was turned out that winter, and it was not until the end of 1867, that digging was resumed. Further portions of the same skeleton were now found, including another instalment of vertebræ, and portions of the skull and jaws. With the latter were several teeth in a suffciently entire state to show that the creature weis undoubtedly a Hippopotamus; numerous fragments of the tusks affording further proof of this. The writer now frequently visited and watched “the diggings,” and after a short time two horn-cores, considerable portions of the skull, and some fragments of the leg-bones of Bison priscus of unusual size came to light. The more perfect horn-core is 18 inches long and 14: inches in diameter at the base.

In the Geological Magazine of December, 1868, appears an article on this subject by Mr. J. R. Gregory, declaring the whole story of the Cape diamond discovery to be “false,” “an imposture,” “a bubble scheme,” got up to promote the expenditure of capital in in searching for this precious substance in the colony; and stating that, from the geological character of the district which he had lately very carefully and thioroughly examined, it was impossible that diamonds had been or could ever be found there.

The occurence of certain of the Lower Silurian Rocks of the Lake-district beneath the Scar Limestone of Yorkshire, on a line between Ingleton and Settle, has been long known, and has been noticed both by Professor Phillips (Trans. Geol. Soc. 2nd series, vol. iii. p.1), and by Professor Sedgwick (Quart. Journ. Geol. Soc. vol. viii. p. 35). More recently the rocks in question have been shortly descrobed in a paper by Mr. Hughes, of the Geological Survey (Geol. Mag. Vol. IV. p. 346). Having had the opportunity of visiting Ingleton in company with Professor HArkness, and subsequently alone, I have collected the following brief notes of the Silurian strata which are seen in that locality, and which belong to the Green Slates and Porphyroes of the Lake-district.