THE PARALLEL ROADS OF GLEN ROY 225 



which the middle and lowest roads are fairly shown. The 

 principal stream running through the glen turns at a cer- 

 tain point northward and loses itself among 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 Roy 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 detrital 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 discovery. 



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 itseK — ^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 account for the absence of the second and 

 third Glen Roy roads from Glen Gluoy, where the moun- 

 tain flanks are quite as impressionable as in Glen Roy. 

 It would not account for the absence of the shelves from 



