212 FKAGMENTS OF SCIENCE. 



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-Lander, 

 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 itself 

 that the parallel roads were formed by the sea ; that 

 this whole region was once submerged and subsequently 

 upheaved ; that there were pauses in the process of up- 

 heaval, 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 Eoy roads from 

 Glen Gluoy, where the mountain flanks are quite as im- 

 pressionable as in Glen Roy. It would not account for 

 the absence of the shelves from the other mountains in 

 the neighbourhood, 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 



