. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 452 TRIAS OF THE UNITED STATES. [Ch. XXH, But tne plants upon the whole are considered by Professor Heer to have the nearest affinity to those of the European Keuper. When Sir Charles Bunbury compared them in 1847 to the fossil plants of Neueweld near Basle, and of other plant-bearing rocks near Baireuth, he supposed, as linger had done before him, that those localities were Liassic, whereas geologists afterwards determined them to be of Upper Triassic date. The foss
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 452 TRIAS OF THE UNITED STATES. [Ch. XXH, But tne plants upon the whole are considered by Professor Heer to have the nearest affinity to those of the European Keuper. When Sir Charles Bunbury compared them in 1847 to the fossil plants of Neueweld near Basle, and of other plant-bearing rocks near Baireuth, he supposed, as linger had done before him, that those localities were Liassic, whereas geologists afterwards determined them to be of Upper Triassic date. The fossil fish are Ganoids, some of them of the genus Catopterus, others belonging to the Liassic genus Tetragonolepis [^Echmodus), see fig. 452 p. 421. Fossil mollusca are very rare, as usually in all coal- bearing deposits, but two species of Entomostraca called Estheria are in such profusion in some shaly beds as to divide them like the plates of mica in micaceous shales (see fig. 490). Fig, a. Estheria ovata. b. Young of same. Oolitic coal-shale, Eichniond, Virginia. These Virginian coal-measures are composed of grits, sandstones, and shales, exactly resembling those of older or primary date in America and Europe, and they rival or even surpass the latter in the richness and thickness of the coal-seams. One of these, the main seam, is in some places from 30 to 40 feet thick, composed of pure bituminous coal. On descending a shaft 800 feet deep, in the Blackheath mines in Chesterfield County, I found myself in a chamber more than 40 feet high, caused by the removal of this coal. Timber props of great strength supported the roof, but they were seen to bend under the incumbent weight. The coal is like the finest kinds shipped at New- castle, and when analysed yields the same proportions of carbon and hydrogen—a fact worthy of notice when we consider that this fuel has been derived from an assemblage of plants very distinct specifically, and in part generically from those whic
Size: 1890px × 1322px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
