Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/52

42 This secondary limestone is accompanied by the magnesian limestone, but I cannot say that the one overlies the other. They rather seem to occur by separate beds, or sometimes by patches, the one within the other. The magnesian limestone does not put on that regular stratified appearance which is so conspicuous in the other, nor have I observed in it any organic remains but in one single instance, and they are similar in their composition to the stone itself.

Mr. Parkinson has most obligingly furnished me with a list of the organic remains contained in the limestone of the Isle of Man, and he farther remarks, that the whole much resemble those found in Westmoreland, Cumberland, Durham, and, as far as he can judge, those of Kilkenny in Ireland.

The following are the organic bodies contained in the specimens that were submitted to his examination.

A large madrepore from two to three inches in diameter with distinct branches, a small madrepore with distinct branches, minute madrepores and entrochitæ, large trochitæ and terebratulæ, the latter varying from two inches to half an inch in diameter, large entrochi, small fragments of minute trochitæ.

The limestone of Castle-town, Scarlet, Pool-vash, and Ball-Fhallack is of a grey, or more generally of a dark grey colour: the texture compact with some lamellar concretions. It is traversed by slender veins of calcareous spar, and the dip-joints are coated