. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Schizodus Sc7ilothei?ni, Geinitz. The hinge of ScMzodus Mytilus septifer, King. Crystalline Limestone, Permian. truncatus, King. Syn. Modiola acuminata. Permian. James Sott. Permian crystalline lime- stone. These shells occur at Hartlepool and Sunderland, where the rock assumes an oolitic and botryoidal character. Some of the beds in this division are ripple-marked; aud Mr. King imagines that the absence of corals and the character of the shells indicate shallow wate
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Schizodus Sc7ilothei?ni, Geinitz. The hinge of ScMzodus Mytilus septifer, King. Crystalline Limestone, Permian. truncatus, King. Syn. Modiola acuminata. Permian. James Sott. Permian crystalline lime- stone. These shells occur at Hartlepool and Sunderland, where the rock assumes an oolitic and botryoidal character. Some of the beds in this division are ripple-marked; aud Mr. King imagines that the absence of corals and the character of the shells indicate shallow water. In some parts of the coast of Durham, where the rock is not crystalline, it contains as much as 44 per cent, of carbonate of magnesia, mixed with carbonate of lime. In other places—for it is extremely variable in structure—it consists chiefly of carbonate of lime, and has con- creted into globular and hemispherical masses, varying from the size of a marble to that of a cannon-ball, and radiating from the centre. Occasionally earthy and pulverulent beds pass into compact limestone or hard granular dolomite. The stratification is very irregular, in some places well defined, in others obliterated by the concretionary action which has rearranged the materials of the rocks subsequently to their original deposition. Examples of this are seen at Pontefract and Rip on in Yorkshire. The brecciated limestone (No. 2) contains no fragments of foreign rocks, but seems composed of the breaking-up of the Permian lime- stone itself, about the time of its consolidation. Some of the angu- lar masses in Tynemouth Cliff are 2 feet in diameter. This breccia is considered by Professor Sedgwick as one of the forms of the pre- ceding limestone, No. 1, rather than as regularly underlying it. The fragments are angular and never water-worn, and appear to have been recemented on the spot where they were formed. It is, therefore, suggested that they may have been due to those internal movements of t
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
