1868. J ARGYLL — ARGYLLSHIRE. * 267 



Pass of Brander is, comparatively speaking, recent. It has been 

 opened across the lofty ridge that stretches from Kings House 

 through Ben Cruachan to the Sound of Jura." Every one reading this 

 description would suppose that this " lofty ridge " was one of toler- 

 ably equal elevation along its whole length, that the Brander Pass 

 had been cut across it in the middle, and that there was nothing to 

 indicate any particular rupture of continuity arising out of geological 

 structure at the particular point where this "deep gorge" occurs. 

 No one would guess that, instead of tying across a continuous ridge, it 

 occurs at the end and termination of the great mass of granitic moun- 

 tains which stretch vi^ith but little interruption from Loch llannoch, 

 through the region of Glencoe, and terminate in Ben Cruachan. 

 But there is nothing like a continuation of this ridge on the other 

 side of the Brander Pass. On the one side rise the highest mountains 

 in Argyllshire, and one of the highest mountains in Great Britain. 

 On the other side is a comparatively low range of hills, wholly dif- 

 ferent in geological structure. I do not say that this general fact is 

 conclusive against Mr.Geikie's theory; but at least it has some bearing 

 upon that theory, and ought to have been mentioned and explained. 

 Of course when a deep gorge occurs at the dividing line between two 

 different mineral systems, the idea is suggested to the mind that this 

 change of structure may possibly have something to do with the 

 fissure which marks its site. Still more clearly, when this deep 

 gorge marks the termination of great upheavals, or, at all events (to 

 use language which involves no hypothesis), marks the end of 

 mineral masses attaining a great elevation, the idea of this sudden 

 depression being due to subterranean force gains much additional 

 probability. But over both these significant facts Mr. Geikie passes 

 in perfect silence. And these broad facts being omitted, it was per- 

 haps hardly to be expected that other facts, requiring still more 

 detailed examination, but perhaps even more significant than any 

 other, should be omitted also, 



I submit, however, that it is a point of great importance to know the 

 aj^pearance which the slates exhibit along this line of junction. It 

 will be observed, in the geological map which is appended to Mr. 

 Geikie's book, that the Avhole left bank of the Awe is represented 

 as occupied by the mica-slates, and that on the right bank of the 

 river also there is a narrow strip of the same material between the 

 river and the great granite mass of Cruachan. Now how do these 

 stratified slates lie on the respective sides of the river ? On the left 

 bank they dip away from the Pass ; and its precipitous sides are com- 

 posed of the escarpment of the strata broken and, as it were, gaping 

 towards the opposite mountain. On the right bank (that is, along 

 the base of Cruachan) the same slates lap round the mountain and 

 are tilted steeply against its sides, which rise so suddenly from the 

 bed of Loch Awe that the road has to be cut into their flank. 



I exhibit a rough section of the relative position of the mineral 

 masses as above described. There are here, in my opinion, evident 

 marks of fracture and dislocation. There have been, apparently, sub- 

 sidences along one line, and corresponding elevations along another ; 



