16*1 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 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 Gleu 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 be 
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 
I 
