330 Dr. MacCullocho///^ Parallel Roads of Glen Roy. 



unworn nature of the fragments, and their identity with the rocks 

 above, appears evidently to have resulted from the wearing down 

 of the summits. But the terraces themselves at the top of the 

 glen vary in composition, and though often composed of the same 

 sharp fragments that overspiead the general declivity, they occa- 

 sionally also exhibit various rolled and transported matters. The 

 conoidal hillocks] which I have just mentioned, as occurring between 

 Glen Fintec and Glen Glastric, are "of a very different composition. 

 Numerous sections of them are to be seen, the result in some cases 

 of a road lately made, in others of the action of water. By these 

 they are shown to consist of deposits of fine sand, gravel, clay, and 

 rolled stones of different sizes, disposed in a manner irregularly 

 stratified, and in a direction more or less horizontal. The terraces 

 and hillocks which occupy positions much inferior to this all the 

 way along the course of the Spean to its entrance into the Lochy, 

 are of the same materials. 



I could perceive no traces of any lines on the left hand, from 

 Glen Glastric downwards, for a space of about two miles. No 

 reason for this deficiency appears, either in the form or compo- 

 sition of the ground. On the contrary it possesses that gentleness 

 of slope and curvature, and that uniformity of alluvial surface on 

 which, in the upper parts of the glen, the lines are always most 

 deeply marked. Nor does it give rise to any streams to the action 

 of which their loss and disappearance might be attributed. Were 

 it not that a similar interruption occurs at a lower point down the 

 glen, as well as in the other vallies connected with it, we might at 

 first suppose that the acting cause had here terminated. It is in no 

 respect different from many of the upper parts of the glen on which 

 the roads are marked, except in the gentleness of its slope. Yet 

 this is insufficient to account for the deficiency, as the appearance 



