42 Dr. Berger on the Isle of Man, 



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 entrochitcC, large trochitas and terebratulje, the 

 latter varying from two inches to half an inch in diameter, large 

 entrochi, small fragments of minute trochitse. 



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 



* This is an expression I beg leave to introduce, and refer to the judgment of 

 Geologists. AH the stratified rocks, but particularly those that have been deposited in 

 a rather horizontal situation, are divided by rents perpendicular to tliLir direction, 

 corresponding therefore with their dip, into solids of dimensions more or less regular, 

 and usually similar in the same individual strata. Thus if the structure of a rock be 

 «iddle thick-slaty, it will divide itself spontancoHsly into rectmisular solids. Whca 



