A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) ... / With 7 plates and 96 textfigures.

British Museum (Natural History). Department of Geology

Date:: 1911

Credit: A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) ... / With 7 plates and 96 textfigures. Source: Wellcome Collection.

166/218 page 138

$Gallery VIII. Table-case 14. Table-case 15. 138 GUIDE TO THE FOSSIL INVERTEBRATE ANIMALS. beds of Beer, in Devonshire, and Westbury, near Bristol. ylviculd coutuvld is the best known, as giving a name to a widely distributed horizon of Bhaetic Age. like the Bhaetic shells generally, it is relatively small, perhaps in conse- quence of brackish water. Monotis decussala and Chlamys vcdoniensis are also important. There is a small but inter- esting series from the Keuper Marls of Warwickshire. The Conchyliau Age has no shell-bearing rock in this country. Permian. This Epoch is represented by marine shells from the Magnesian Limestone of Durham and the red marls near Manchester. Note Monotis speluncuria and Byssoarca striata from the former, and the tiny llissoa and Tarho from the latter. Bakcvxllia antiqna comes from both localities, and from Tyrone as well. Fig. 73.—Recent and fossil shells of Pleurotmiaria. a, P. Quoyana, now living in the West Indies; b, P. plahjspira from the Middle Lias of France. The slit s receives the projecting anus, and, as the shell grows forward, is filled up by shell-substance. Both figures are less than natural size. Carboniferous. The shells of this Epoch come mainly from the C(jal Measures and the Mountain Limestone, the rocks of Middle Carboniferous or ]\Ioscovian age having yielded few mollusca in this country. The Coal Measures, though largely of fresh or brackish water origin, contain many marine bands ; the Lower Carboniferous rocks are all marine. The fossils have not here been separated according to age or rock or habitat. It will, however, be noticed that the Coal Measure fauna, and particularly the freshwater elements in it, occur among the lamellibranchs, whereas the gastropods are almost all from the Mountain Limestone. Among the Coal i\Ieasure fossils are many described by Sowerby in Prestwick’s classical memoir on Coalbrookdale, and many described by Dr. Wheelton Hind in the Mono- graphs of the Palaeontographical Society. The fresh-water forms include Anthracomya and Carbonicola \Antliracosia\$