1863.] JAMIESON PARALLEL KOADS OF GLEN EOT. 259 



to the areas they drain often drew my attention, and the wetness 

 of the climate is (experto crecle) something remarkable. During the 

 glacial period the west side of Scotland may have also had a greater 

 relative elevation, which would further increase the size of the 

 glaciers. 



The clearness of the evidence in Lochaber leads me to think that 

 those accumulations in the glens of Braemar which I examined and 

 described in 1859, and of whose origin I then felt doubtful, cannot 

 be marine, but must be attributed to freshwater action and the 

 agency of glaciers*. 



§ 8. Recapitulation. 



To recapitulate, then, the following are the conclusions I have 

 been led to by my examination of Lochaber : — 



1st. That the Parallel Roads are the beaches of freshwater lakes. 



2nd. That these lakes seem to have arisen from glaciers damming 

 the mouths of the valleys and reversing their drainage. 



3rd. That the date of these lakes is posterior to the great land- 

 glaciation of Scotland. 



4th. That neither the sea nor any diluvial catastrophe has, since 

 the time of the lakes, approached the 850-feet line. Therefore the 

 chief submergence of the glacial period must have preceded the 

 formation of the roads, or else not have been so extensive as to 

 reach them. 



5th. The glens of Ben Nevis do not appear to have been occupied 

 by the sea since the glaciers finally left them. 



6th. The 40 -feet raised beach of Argyleshire extends to Fort 

 "William, and is later than the large glaciers. 



7th. The Mollusca of this old 40 -feet coast-line were of a more 

 northern character than those now inhabiting our shores. 



I hope some geologists who have studied glacier-action may be 

 induced to visit this most interesting tract, and either confirm or 

 disprove the above conclusions. 



For the information of intending visitors, I may mention that there 

 is an inn at Spean Bridge, and another at the east end of Loch Lag- 

 gan ; also one of smaller size at Bridge of Boy. The locality can be 

 best approached by leaving the Caledonian Canal steamer at Gair- 

 lochy, near the mouth of the Spean, and walking or driving up to 

 Spean Bridge, a distance of three miles. There are good hotels at 

 Bannavie and Fort William. 



* Even the deep mass of stratified matter on the flank of Meal Uin, near 

 Killiecrankie, described by me in the Quart. Journ. Geol. Soc. vol. xvi. p. 359, 

 and which I thought a good evidence of marine action, from the insuperable 

 difficulties of supposing any ordinary freshwater lake to have existed in that 

 locality capable of explaining it, may possibly be accounted for by supposing it 

 to have been lodged in a deep pool filling the gully, and confined between the 

 mountain and the side of a large glacier occupying the valley of the Tummel. — 

 See Charpentier's Essai sur les Glaciers, p. 64, for an explanation of similar 

 occm'rences in the Alps ; also Ly ell's Antiquity of Man, p. 245 ; and Agassiz, 

 Etudes sur les Glaciers, pp. 217-288. 



