. Elements of geology. Geology. a. Microconchus Cypris inflata, natural carbonarius. size, and magnified. h. var. of same, nat. Murchison.* size, and magnified. of plants, including a bed of limestone, varying from two to nine feet in thickness, which is cellular, and re- sembles the lacustrine lime- stone of France and Ger- many. It has been traced for 30 miles in a straight line, and recognized at more distant points. The charac- teristic fossils are a small bivalve, having the form of a cyclas, a small cypris, (Fig. 245.) and a miscrosco- pic shell, (microconchus) of an extinct genus. But i
. Elements of geology. Geology. a. Microconchus Cypris inflata, natural carbonarius. size, and magnified. h. var. of same, nat. Murchison.* size, and magnified. of plants, including a bed of limestone, varying from two to nine feet in thickness, which is cellular, and re- sembles the lacustrine lime- stone of France and Ger- many. It has been traced for 30 miles in a straight line, and recognized at more distant points. The charac- teristic fossils are a small bivalve, having the form of a cyclas, a small cypris, (Fig. 245.) and a miscrosco- pic shell, (microconchus) of an extinct genus. But in the lower coal-measures of Coalbrook Dale, the strata, according to Mr. Prestwich, often change completely within very short distances, beds of sandstone passing horizontally into clay, and clay into sandstone. The coal-seams often wedge out or disappear; and sections, at places nearly contiguous, present marked lithological distinctions. In this single field, in which the strata are from 700 to 800 feet thick, between 40 and 50 species of terrestrial plants have been discovered, besides several fishes and trilobites; the latter distinct in form from those occur- ring in the Silurian strata. Also upwards of 40 species of mol- lusca, among which are two or three of the freshwater genus Unio, and others of marine forms such as Nautilus, Orthoceras, Spirifer, and Productus. Mr. Prestwich suggests, that the inter- mixture of beds containing freshwater shells with others full of marine remains, and the alternation of coarse sandstone and conglomerate with beds of fine clay or shale containing the re- mains of plants, may be explained by supposing that the deposit of Coalbrook Dale, originated in a bay of the sea or estuary into which flowed a considerable river subject to occasional In the Edinburgh coal-field at Burdiehouse, fossil fishes, mol- lusca and cypris, very similar to those in Shropshire and Staf- fordshire, have been found by Dr. : In the coal-field
Size: 1226px × 2039px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlyellcharlessir17, bookcentury1800, booksubjectgeology
