162 FRAGMENTS OF SCIENCE. 



loses itself among the hills too high to offer any outlet. But 

 another branch of the glen turns to the southeast; and, 

 following up this branch, Mr. Milne-Home reached a col, 

 or watershed, of the precise level of the second Glen Eoy 

 road. When the barrier blocking the glens had been so 

 far removed as to open this col, the water in Glen Roy 

 would sink to the level of the second road. A new lake of 

 diminished depth would be thus formed, the surplus water of 

 which would escape over the Glen Glaster col into Glen 

 Spean. The margin of this new lake, acting upon the dc- 

 trital matter, would form the second road. The theory of 

 Sir Thomas Dick-Lauder, as regards the part played by 

 the cols, was re-riveted by this new and unexpected dis- 

 covery. 



I have referred to Mr. Darwin, whose powerful mind 

 swayed for a time the convictions of the scientific world in 

 relation to this question. His notion was and it is a 

 notion which very naturally presents itself that the par- 

 allel roads were formed by the sea; that this whole region 

 was once submerged and subsequently upheaved; that there 

 were pauses in the process of upheaval, during which these 

 glens constituted so many fiords, on the sides of which the 

 parallel terraces were formed. This theory will not bear 

 close criticism; nor is it now maintained by Mr. Darwin 

 himself. It would not account for the sea being 20 feet 

 higher in Glen Gluoy than in Glen Roy. It would not ac- 

 count for the absence of the second and third Glen Roy 

 roads from Glen Gluoy, where the mountain flanks are 

 quite as impressionable as in Glen Roy. It would not ac- 

 count for the absence of the shelves from the other moun- 

 tains in the neighborhood, all of which would have been 

 clasped by the sea had the sea been there. Here then, and 

 no doubt elsewhere, Mr. Darwin has shown himself to bo 

 fallible; but here, as elsewhere, he has shown himself equal 

 to that discipline of surrender to evidence which girds his 

 intellect with such unassailable moral strength. 



But, granting the significance of Sir Thomas Dick- 

 Lauder's facts, and the reasonableness, on the whole, of 

 the views which he has founded on them, they will not 

 bear examination in detail. No such barriers of detritus as 

 he assumed could have existed without leaving traces be- 

 hind them; but there is no trace left. There is detritus 

 enough in Glen Spean, but not where it is wanted. The 



