Ancient Moraines in Argyleshire. 195 



little doubt that striated surfaces may be found, when more 

 carefully sought for ; but from the position of the strata, in 

 reference to the direction of the valley, we cannot expect them 

 to be numerous. Striae and groovings are most deeply cut 

 and best preserved on schistose rocks, when the line of glacier 

 motion runs across the edges of the strata, while in Glensluan 

 it coincides with the strike. 



In the form, then, of these mounds, in the materials com- 

 posing them, and in the position which they occupy, we have all 

 the essential features of the terminal moraine, and in the valley 

 above, we have the mould in which the ancient glacier was cast, 

 and in which a glacier would certainly be again found, were 

 the necessary climatic conditions to recur. 



If we reject the glacier hypothesis, the existence of these 

 mounds cannot be accounted for. The small stream of the 

 valley has done something to destroy them, but neither it nor 

 a much larger stream could possibly produce them ; and the 

 effect of debacles, oceanic currents, and similar cosmical 

 agents, in whatever way employed, would be, not to raise such 

 objects, but to level them. These oddly-shaped and oddly- 

 placed piles of gravel must have remained a puzzle, if the icy 

 regions of the Alps had not furnished a key to explain them. 



Immediately above the upper mound a, in Fig. 4, a smaller 

 one, x, will be observed. It is the lower end of a ridge of the same 

 materials (gravel and clay) which ascends from two to three 

 hundred feet on the western declivity. It projects two or 

 three yards from the surface of the hill at the head, and thick- 

 ens to 30 or 40 feet at w, the foot. It has a large conspicuous 

 boulder resting on its upper end, and there is a similar ridge 

 running parallel with it, immediately above it in the valley. 

 They are probably portions of a lateral moraine, passing here 

 into a terminal one. 



Glensluan joins Glen Eck, and it is possible that the lowest 

 portion of the mounds may belong to the latter. Similar de- 

 posits of gravel and sand are found on both sides of Glen Eck. 

 They are peculiarly abundant from Whistlefield to Strachur, 

 and, though not in the distinct form, are probably the rem- 

 nants or wrecks, of lateral moraines. At the junction of the 

 two glens, the materials would be mingled, and it may be dif- 



