38 Mr. J. Bryce's Notices of a late Visit 



ledges the " singular distinctness " of the shelves in this loca- 

 lity ; yet his theory affords no explanation of a phenomenon 

 so remarkable. But this argument has been so ably handled 

 by Mr. Milne in his reply to Mr. Darwin (Ed. N. Phil. Journ., 

 vol. xliii. p. 437), that it is unnecessary to insist further 

 upon it. 



The faint and higher markings on the south side of Glen 

 Spean, which Mr. Chambers lays so much stress upon as sup- 

 porting his view, I did not notice. " The whole," he says, 

 " might appear doubtful to many persons ; in an unfavourable 

 light, a hasty observer might pass them by altogether unno- 

 ticed." These may have been my circumstances, and I do 

 not therefore question the existence of such markings ; but I 

 cannot regard the conclusion as warranted by the facts — the 

 existence, namely, " in Glen Spean of a body of water at 

 levels above the barriers assigned to it by M c Culloch, Lauder 

 and Milne." Are not these and similar slight and local mark- 

 ings best explained on the received theory, — the action of cur- 

 rents upon the submerged land, or the occasional pauses in 

 the process of elevation ? 



While thus dissenting from the theoretical conclusions at 

 which Mr. Chambers has arrived, I cannot forbear to express 

 my high admiration of his patient and active research, — his 

 clear, truthful, and eloquent descriptions, — and of the service 

 he has rendered to geology by his many exact measurements, 

 and by proposing a theory which will lead to a more careful 

 study of phsenomena of this class. 



The lake theory has gained immensely of late by the ad- 

 vocacy of Mr. David Milne. His paper, already referred to, 

 is perhaps the most able which has been written upon the 

 Parallel Roads. The evidence in support of his own views has 

 been collected with the greatest sagacity, and the arguments 

 founded upon it conducted with consummate skill ; while he 

 appears to me to have completely demolished both the theory 

 of Mr. Darwin, and the glacial theory, in the form proposed 

 by M. Agassiz. The agency assigned by Agassiz will not 

 explain all the phsenomena, and is positively inconsistent with 

 many facts. But it does not hence follow that glacial action 

 is to be rejected, as explaining the blocking up of the mouths 

 of the glens, — for it is required for this purpose alone. May 

 not a form be given to the theory which will adapt it to all 

 the exigencies of the case, and thus remove from the lake 

 theory the one great remaining objection — the origin and the 

 disappearance of the enormous earthy barriers at the mouths 

 of the glens? Since Agassiz wrote, the question has been 

 placed on a very different footing. The first glacialist in 



