528 REV. R. B. WATSON ON THE GREAT DRIFT-BEDS WITH SHELLS 



boulder-clay is very hard. Through it there runs a stratum of fine clay 3 or 

 4 inches thick. Above the boulder-clay is a great bed of sand, in some places 

 35 feet thick, but diminishing rapidly in depth as the bank slopes downwards to- 

 wards the sea. 



At the mouth of Glen Ashdale, the boulder-day beds lie deep over the whole 

 hill side to the north. They are also present, but in a very ruinous state, on the 

 south. 



Between Whiting Bay and the Torlin Burn they are everywhere to be seen, 

 but I did not examine them minutely. 



In the Torlin Burn, and especially in the Cloinoid branch of it, they are im- 

 mensely developed, and present the best sections I have seen in Arran. The beds 

 also contain shells. 



At the farm of Torlin, on the edge of the sea cliff, the boulder-clay rises from 

 the beach to 110 feet above the sea. On the road above Lag, at the schoolhouse, 

 it is 150 feet above the sea. This is just above the edge of the great red banks, 

 which rise steep and broken from the burn, and run on uninterruptedly for a couple 

 of miles. The first place where I found shells in these banks was on the east 

 side of the burn, 120 feet above the sea (Plate XXL, fig. 1), and about 15 or 20 feet 

 below the top of the bank, which is here 50 or 60 feet high. 



Just below the Church of Kilmorie, the burn is crossed by a little wooden 

 bridge. Immediately below the bridge, on the west side of the burn, 80 feet 

 above the sea, is an extremely interesting section. The bank is 100 feet high, but 

 is much obscured by sludge. The boulder-clay, however, can be made out in detail 

 nearly to the top of the bank. At the edge of the burn course, the sandstone is 

 laid bare. It is very considerably hardened by a greenstone dyke, which lies here 

 in the burn course. The face of sandstone slopes quietly up from the level of the 

 burn for 4 or 5 feet. If it Avas ever striated, the burn has effaced the markings, the 

 whole surface having been evidently exposed for a considerable time. Its upper edge 

 is perpendicularly broken off on an irregular line ; and at the back of this edge, the 

 curious succession of beds shown in the accompanying sketch can be made out. 

 (Plate XXL, fig. 2). The impression which they produced on my mind was, that 

 the under beds to No. 6 or 7 had been formed by running water under a glacier, 

 and had been jammed in at the back of the rock by the ice moving downwards, 

 not directly in the line of the present burn course, but obliquely across it from the 

 north-west, while the other beds above, from No. 8 onwards, were deposited in 

 the sea. In any case the presence of the sea during the formation of beds Nos. 

 10 and 11 is certain, from the presence of shells in both of them. In No. 10 I 

 found a few unbroken Ledas in pairs ; and in No. 1 1 , besides fragments of Ledas 

 two broken Turritellas, and a small bit of a Litorina litorea. This last bed is 

 harder and darker than No. 13 ; and the stones, which are well striated, are fewer 

 and smaller, but both beds are distinctly boulder-clay. Bed No. 10 seems to dip 



