56 MR SMITH ON THE CHANGES 



Argyleshires, about double that distance ; the granite blocks 

 must have been transported from still greater distances. 

 Beyond the Kilpatrick Hills the trap and white sandstone 

 boulders disappear, and are replaced by greywacke, clay- 

 slate, and red sandstone, whilst those of granite and mica- 

 slate become numerous. Near Helensburgh, twenty-three 

 miles to the north-west of Glasgow, the granite strongly re- 

 sembles that of Ardnamurchan. At Roseneath, I have 

 seen rolled fragments of a compact reddish granite so much 

 resembling that of Inverary, as to leave little doubt of its 

 identity. In all of these cases, the bearing of the supposed 

 original rocks is north-west, but in all of them the interven- 

 ing space is intersected by deep arms of the sea and steep 

 precipitous mountain ranges. It appears to me, therefore, 

 that the till is as ancient as the period of their elevation, and 

 was most probably caused by the violent geological action 

 by which it was accompanied. 



It is, at all events, in Scotland anterior to the marine al- 

 luvia which I am describing, and which have been observed 

 reposing upon it in many places. It is proper, however, to 

 observe, that in some instances we find stratified alluvium 

 below the till. I have observed this near Glasgow, and on 

 the west coast of Ireland ; and Mr Bald, in describing that 

 of the Forth, remarked, that in one case, when t was cut 

 through to the depth of 162 feet, the lower bed appeared to 

 have been deposited in water in the most quiescent state, as it 

 was divided into the finest laminae. In neither of these cases 

 were marine remains detected, but Mr Mantell has describ- 

 ed an ancient beach as passing under the elephant bed in 

 Sussex, and Sir Philip Egerton found a bed of shells under 

 the ordinary sand diluvium of Cheshire.* These facts do 



* Proc. Geol. Soc. vol. ii. p. 190. 



