Reports and Proceedings

42 Reports and Proceedings. Journal. Mr. Churchill suggests that the formation of Dolomite may be going on in coral reefs at the present day ; for the speci- mens of coral rock brought home by Dana from the raised island of Matea, or Aurora, were found to contain in one case 5 per cent., and in another as much as 38 per cent., of carbonate of magnesia. And if we suppose the Dolomite mountains of Carinthia to have been formed on a gradually subsiding basis, they may have grown up like the low islands of the Pacific, till the sea attained the depth of a thousand fathoms, preserving their original contour from first to last, the groups of corals, like a forest of tree-trunks without tops, rising upwards together, and becoming partially solid by lateral growth, or by filling up with sediment. We have no fossil coral-reef in England wherewith to compare the Dolomite Mountains. Our Magnesian limestone affords only Bryozoa, for it has not been suspected that the remarkably concentric and radiated concretions are metamorphosed corals. In our Silurian coral-reef of the Wenlock Edge and Dudley there may be masses of branching coral a yard across, and convex StromatoporcB (which are not corals) of nearly equal size. But the coral-beds are separated by clay partings, and never attain a great thickness. The Devon- shire marbles have much the appearance of coral-reefs, so far as respects the scattering of small masses over a region of argillaceous schists. In the Carboniferous Limestone layer above layer of branching corals may be seen in the lofty cliffs of Cheddar and the weather- beaten shores of Lough Erne. There the corals are slightly silicified, and stand out in relief, while the mass of the rock is composed of sediment with Foraminiferal and Encrinital debris. The Coral-rag forms a reef in some parts of Wiltshire, but it is rarely seen in section ; the corals are usually obtained as stones from the ploughed fields. The conversion of a limestone coral-reef into Dolomite becomes comparatively easy of belief, since Mr. Sorby has shown that coral (like nacre) has the constitution of aragonite, a much less stable compound than calcareous spar. Pearly shells are never preserved in calcareous rocks, unless in a metamorphic condition. And the corals of the Oolite formation are usually silicified, like those of Tisbury in Wiltshire and Nattheim in Germany, orreplaced by structureless calcite full of sparry cavities. It is now also well-known that the masses of annulated chalcedony, called ' Beekite,' found in the neighbourhood of Torquay, are Devo- nian corals more or less completely replaced by silica, for they are sometimes hollow, and in other instances contain a nucleus of fossil coral. EEPOETS .A-INTO PROCEEDIlvra-S. THE GEOLOGICAL SOCIETY OF LONDON. THE following communications were read, May 25, 1864 :— 1. ' On the Geology of part of the North-western Himalayas.' By Captain Godwin-Austen. With Notes on the Fossils ; by Messrs. T. Davidson, R. Etheridge, and S. P. Woodward. Reports and Proceedings. 43 The geological formations occurring in these regions were stated to be (1) a fluvio-lacustrine series, (2) a Siwalik series, (3) Nummu- litic Limestone, (4) Jurassic rocks, and (5) a Palaeozoic series. In reference to the fluvio-lacustrine strata, the author gave a resume of the conclusions respecting their physical features and mode of formation at which he had arrived in a former paper,* and in addition gave some details respecting their position and stratigraphical cha- racters, especially describing the mode of occurrence in them of some land and freshwater Shells, which were referred to in a Note by Mr. S. P. Woodward, as being all recent British species. The lakes in which the lacustrine deposits were formed were supposed by Capt. Godwin-Austen to have been produced in consequence of the mouths of valleys, into which rivers run, becoming blocked up by means of glaciers and otherwise, as now often happens in the same region. Stratigraphical details of the other series of rocks were then given, the Jurassic formation being supposed to belong to the Middle Division of the Oolites, and the Palasozoic limestone being described as Carboniferous Limestone, both of which determi- nations were confirmed by Messrs. Etheridge and Davidson in Notes on the Fossils, in which their striking resemblance to those of the same age in Britain was shown. The age of the clay-slate and mica- slate was stated to be very doubtful; and the author concluded by describing the localities in which granite rocks occur, but chiefly as forming the axis of the North-western Himalayas. 2. ' On the Cetacean Fossils termed Ziphius by Cuvier, with a notice of a new species {Belemnoziphius compressus) from the Red Crag.' By Prof. T. H. Huxley, F.R.S., F.G.S. The genus Ziphius, as originally constituted by Cuvier, contained three species described by him, namely, Z. cavirostris, Z. planirostris, and Z. longirostris; but it is probable that each of these really belongs to a distinct genus—the first to Ziphius, the second to Choneziphius, and the last to the author's genus Belemnoziphius. More recently M. Gervais has established a new species—Ziphius Becanii—from a specimen formerly considered to belong to Z. longirostris ; and this species, with that described in this paper, and Professor Owen's MS. species in the British Museum, were also considered referable to Belemnoziphius. Besides the foregoing conclusions respecting the affinities of the fossil Rhynchoceti, Professor Huxley discussed the relations of the recent genera and species of the same group, including the Ceta- cean of Aresquiers, which was considered by Gervais to belong to the genus Ziphius. He exhibited these relations in a tabular form, and concluded by stating that he had arrived at the following results :^— 1. Unless the Cetacean of Aresquiers be identical with Ziphius cavirostris, all the Ziphii of Cuvier belong to Cetacea generally distinct from those now living. 2. If the Cetacean of Aresquiers be identical with Ziphius cavi- * Quart. Journ. Greol. Soe., vol. xv. p. 221. 44 Reports and Proceedings. rostris, it is not certain that the latter is truly fossil; nor, if it be so, have we any knowledge of its strati graphical position. 3. Of the certainly fossil Ziphii, the stratigraphical position of Belemnoziphius longirostris is unknown; but all the other species of that genus, and Choneziphius planirostris, are derived from the English or Antwerp Crag, and are not known to occur out of it. 4. So that at present we are justified in regarding Belemnoziphius and Choneziphius as true Crag Mammals. The following communications were read, June 8, 1864 :— 1. ' On the Rhaetic Beds and White Lias of Western and Central Somerset, and on the discovery of a new Fossil Mammal in the Grey Marlstones beneath the Bone-bed.' By W. Boyd Dawkins, Esq., B.A., F.G.S. After describing the sections in the district, and showing the palaeontological relations of the White Lias to the Avicula contorta series and the zone of Ammonites planorbis, the author enunciated the following conclusions:—(1) That the true position of the White Lias is immediately above the Avicula contorta zone of Dr. Wright, and at the base of the Lower Lias shales ; (2) that it is entirely distinct from the Rhaetic beds, lithologically and palseontologically; and (3) from the discovery of Rhaetic fossils in the Grey Marls below the Bone-bed, that the latter belong to the Rhaetic formation. He then proceeded to describe a two-fanged mammalian tooth, which he had found in the Grey Marlstones below the Bone-bed, and which he considered to be the analogue of the trenchant four- ridged premolar of Hypsiprymnus, of the section to which H. Hun- teri belongs. Until additional remains be found, its affinities to Microlestes or to Plagiaulax cannot be determined ; Mr. Dawkins has, therefore, named it provisionally Hypsiprymnopsis Rhcelicus. In conclusion he traced the range of the Marsupials in space and time, showing that of the six families into which Van der Hoeven divides the existing Marsupials, two—the entomophagous and sarcophagous Dasyurina, and the phytophagous Macropoda. — had been repre- sented in England during the interval between the deposition of the Rhaetic Marlstones and that of the Purbeck beds. 2. ' On the Geological Structure of the Malvern Hills and ad- jacent District.' By Harvey B. Holl, M.D., F.G.S. The geological structure of these hills was described in detail, and it was concluded that the rocks hitherto treated of as syenite, and supposed to form the axis of the range, are in reality of metamorphic origin, consisting of gneiss (both micaceous and hornblendic), mica- schist, hornblende-schist, &c, all invaded by veins of granite and trap-rocks. It was then shown that the Hollybush Sandstone is the equivalent of the Middle Lingula-flags, and that the overlying black shales correspond with the Upper Lingula-beds, the whole being overlain, as in Wales, by Dictyonema-shales. These rocks, on the east of the Herefordshire Beacon, are altered by trap-dykes, which were shown to be of later date than those traversing the crystalline rocks before alluded to. Allusion was next made to the Upper Reports and Proceedings. 45 Llandovery strata which overlie unconformably the Primordial rocks just noticed; after which the several faults in the district were described in detail. Dr. Holl concluded with some remarks on the general relations of the rocks of the Malvern Hills with those of the surrounding districts, describing the successive physical changes supposed to have been consequent upon their deposition and their subsequent elevations and depressions.

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