30 Rev. A. Sedgwick and Mr. Murchison on the Geological 



merate from each other, and to arrang^e them with the analogous members of 

 English geology. In one respect, however^ these deposits differ materially 

 from those of the same age in England, since there appear to have been no 

 disturbing forces to interrupt the continuity and conformity of the beds from 

 the base of the older conglomerate, through the carboniferous series, up to the 

 highest beds of the new^ red conglomerate ; — these several formations being 

 not only parallel to, but actually graduating into each other. 



Carboniferous Series. 



At the north end of the village of Corry we meet with beds of white sand- 

 stone and grit, similar in the ascending order to those which have been de- 

 scribed in the sections of the descending series as interposed between the old 

 red sandstone and the mountain limestone ; but here they occupy a much less 

 breadth, which may easily be accounted for by the thinning out of the shale 

 and coaly beds, and the omission of those large interpolated masses of trap 

 which occur at Groggan Point. At Corry the mountain limestone succeeds, 

 and is extensively quarried for several hundred yards along the hill side, from 

 caverns which are excavated upon the dip, which is S.S.E. 40^ The beds are 

 of strong and nearly compact grayish blue limestone, much veined, about 

 twenty in number, from eight to ten inches thick, and separated by bands of 

 red shale, the whole surmounted by a magnesian limestone of four feet in 

 thickness. Beds of precisely the same magnesian composition are very com- 

 mon in all formations of mountain limestone, and are here simply worthy of 

 remark, because they are found in the same position in other quarries of lime- 

 stone in Arran. 



Among the fossils, specimens of the large Producta Scotica are so abundant 

 as entirely to form the lower layer of many of the beds ; being arranged very 

 symmetrically in the exact position of the living shale, with their convex valves 

 downwards, and pressed into the red shale. Among the fossils are also Spirifer 

 striatus, encrinital stems of large size, Cardimn alceforme, and the madrepo- 

 rites so common in the mountain limestone. 



The limestone is overlaid by a succession of strong beds of freestone, which 

 have been much worked, but are now in disuse, the finest qualities of flagstone 

 having been extracted : a series of specimens might however be derived from 

 these quarries identical with the common grits of the English coal-measures; 

 and the existence here of several coal plants in a position similar to those de- 

 scribed at the salt-pans completes the analogy. To the south of Corry com- 

 mences a series of dislocations marked by corresponding advances of the granite 

 from the central ridge, each of which seems to have produced an upcast in the 



