TWO GLENS AND THE AGENCY OF GLACTATION. 199 



especially to the peaks, conies, and precipices of Ben Buie, which rises to the height of 

 3100 feet. If local glaciers had been formed anywhere in the whole district, they must 

 have been formed on the tops and flanks of this mountain — and they must have moved 

 down Glenshira if they had acted as all such bodies do elsewhere. Two very deep and long- 

 ravines, each of them draining large surfaces of mountainous slopes and moors, fall into the 

 head of Glenshira : and it is quite impossible that, if local glaciers were ever formed in 

 Glenaray, they should not have been also formed, and in much greater volume, at the top 

 of Glenshira. There is, indeed, no comparison between the extent and elevation of the 

 gathering ground at the head of Glenshira and the comparatively trifling area capable of 

 serving the same purpose in the case of Glenaray. The conclusion is inevitable that the 

 agency which seems to have been present in great force in Glenaray, and to have been 

 cither wholly absent or else very subordinate in Glenshira, must have been something 

 entirely different from a local glacier — something to which Glenaray was much exposed, 

 and from which Glenshira, on the contrary, was much sheltered. 



The question is then forced upon us — whether there is any distinctive feature in the 

 physical geography of the two glens which can afford any explanation to this apparent 

 mystery. But the moment this question is asked, we are guided to a most significant reply. 

 There is one, and only one, great distinction between the two glens — namely, this : that 

 Glenaray terminates in a low pass or watershed only 480 feet above the level of the sea, 

 over which the road passes from Loch Fyne to Loch Awe, and that it gapes as with a 

 bell-mouthed opening to the valley of Loch Awe in the directions of N. to N.E. Glen- 

 shira, on the other hand, is a glen completely closed in that direction by successive ridges 

 of mountains, which rise from 1800 and 1600 to at least 2000 feet above the same 

 level, and present no pass at all from the valley of Loch Fyne to the valley of Loch Awe. 

 Looking up Glenaray from the town of Inveraray, we see a low horizon and the peaks of 

 Ben Craachan, on the other side of Loch Awe, fully exposed to view. Looking up Glen- 

 shira from a corresponding point at its mouth, our view is bounded by steep mountainous 

 ridges, which close it completely, and behind these ridges by a high screen of elevated 

 moorland, which constitutes an horizon line of at least 1500 feet high. In short, the 

 one circumstance in which the two glens differ is this — that the one is completely open 

 and unprotected to an agency moving from beyond it in a north-easterly direction, 

 whilst the other glen is completely protected from any such agency by a lofty protecting 

 wall of mountains. Of course, the significance of this great difference is immense the 

 moment we connect it with the idea that the glaciating agency was floe ice floating 

 in a sea which at one time rolled over all our hills up to the level of from 1500 to 

 2000 feet, and which, in both its rising and in its falling stages, must, of course, have been 

 deflected in its currents by many lower elevations, which would afford complete shelter to 

 some glens from the scour to which others, with a lower watershed, were exposed. It 

 seems to me that all the differences and peculiarities of these two glens, with reference to 

 the marks left by the glacial ages in the one, as compared with the other, are explained 

 by the corresponding distinction between them with reference to the physical geography 



