156 GEOLOGY OF THE LOTHIANS. 



The junctional appearances of the granite and sandstone, 

 to which we refer, occur in the island of Arran, and are only 

 to be observed in a stream which enters the sea near the 

 village of Corry. At this point, when at a distance from 

 the granite, strata of slate-clay and red sandstone are found 

 dipping S. S.E. at 30°, the sandstone frequently passing in- 

 to conglomerate, and containing rolled masses of quartz- 

 rock. On advancing from the sea to the mountain, how- 

 ever, the rocks progressively assume a greater inclination, 

 till at last, near a mural escarpment of granite, they assume 

 a nearly vertical position ; the stratified arrangement of the 

 sandstone also, which is in general perfectly distinct, be- 

 comes then very much obliterated, and the red colour of 

 the strata entirely disappears. At the immediate junction 

 of the sandstone and granite, which is only visible for about 

 four feet, the former passes into a perfect granular quartz- 

 rock ; the granite also exhibits characters completely dif- 

 ferent from those which it has when at a distance from the 

 sandstone, and instead of being a distinct crystalline ag- 

 gregate of quartz, felspar, and mica, it becomes a rock 

 composed entirely of the two first, which are not arranged 

 in distinct granular concretions, but, on the contrary, are 

 blended intimately the one with the other. From the great 

 thickness of the series of clay and chlorite slates, which 

 in every part of Arran, with the exception of a short dis- 

 tance along the base of the hills which rise above Corry, 

 lies always between the granite and the secondary rocks, it 

 is vain to seek for junctions of the granite and the sand- 

 stone in other parts of the island. The one, however, which 

 we were fortunate enough to find, though of limited extent, 

 renders the fact that the granite has been protruded after 

 the deposition of the sandstone sufficiently evident. In a 

 paper published by Messrs Sedgwick and Murchison, in 

 the Transactions of the Geological Society of London, "On 



