340 Dr. Mac Culloch on the Parallel Roads of Glen Roy. 



Fortunately it is not material with regard to the general results that 

 must follow from considering the phenomena of Glen Roy, since 

 these will be still nearly the same although these glens had not ex- 

 isted. The glen of Loch Eil however, which I have examined, re- 

 quires a more detailed description, as it is probably implicated in the 

 consequences which will follow from one of the theories that must 

 be had recourse to in explaining the appearances of Glen Roy. 



The valley of the Spean and that of the western branch of Loch 

 Eil may be considered as opening into the great Caledonian valley 

 by a common wide mouth ; while the southern bend of Loch Eil 

 lies in a valley comparatively narrow, formed by the skirts of Ben 

 Nevis on one side, and the hills of Ardgowar on the other. It is 

 necessary to keep this circumstance in mind till the probable causes 

 of the lines in Glen Roy are brought under review. A valley of a 

 dead level extends to the head of Loch Eil, which being little higher 

 than the loch is of course elevated but a few feet above the sea, of 

 which its water forms a branch. From the head of this loch another 

 gentle rise conducts to the head of Loch Shiel, a fresh water lake, 

 which occupying a narrow prolonged valley, at length descends by 

 a gentle declivity into the sea at Loch Moidart. I cannot give the 

 elevation of Loch Shiel, which is nearly the highest point of this 

 level, but from an estimate formed on the ground, which at any rate 

 cannot be so far in error as to affect the question, conclude it to be 

 inferior to all the lines of Glen Roy, the lowest of these being 976 

 feet above Loch Eil. Water therefore, if we could now imagine 

 it raised to the levels of the lines of Glen Roy, would run to the 

 sea at Loch Moidart, as well as at Loch Eil, and at the Moray 

 Firth.* 



Returning to the head or eastern communication of Glen Roy, 



* Pi. 19. 



