part 2] THE SOUTH-WEST HIGHLANDS OE SCOTLAND. 85 



It was in 1914 that I arrived at what are virtually my present 

 conclusions. For some 3^ears previously my thoughts had ever 

 turned to the difference characteristic of the two sides of the Loch- 

 Awe Syncline, below the level of the Ardrlshaig Phyllites (PI. I).i 

 It seemed fairlj^ certain from the beginning that a thrust (or lag) 

 was in some way responsible ; but it was not until shortly before 

 the outbreak of war that I attained to anything approaching full 

 illumination. In the hope that someone else might finish the 

 work if I should not be able to do so, I summarized the leading 

 facts and suggestions as an appendix to a paper on the Islay Anti- 

 cline published, during my absence, hj this Society. However, 

 this proffered page-long appendix was refused, on the ground that 

 it was incom^Dlete. 



Clougli^s Secret of the Highlands. 



I wish to take this opportunity of acknowledging that the 

 interpretation of the South-West Highlands, sketched in the 

 preceding section, is essentially a continuation of C. T. Clough's 

 interpretation of Cowal. To mention but one of his claims on 

 our gratitude, Clough will always be remembered as having 

 introduced a new element of technique into the investigation of 

 Highland problems. Everybody, since the dawn of geology, has 

 employed eroded anticlines and synclines in the elucidation of 

 stratigraphical successions and variations in relatively undisturbed 

 regions of low relief. Clough boldly extended their use to the 

 investigation of the folded complexes of the Highland Schists, 

 where close study of a comparatively late anticline or syncline may 

 throw invaluable light on the scope and character of earlier folds 

 and systems of folds. Long before his day the Cowal Anticline 

 had been recognized as a conspicuous feature of South- West High- 

 land geolog}?" (1861 fi^, p. 135). After very detailed consideration 

 of 'this structure, Clough states his conclusions regarding it as 

 follows (1897, p. 83) :— 



'• There is no doubt that this anticline is a true arch of an early foliation. 

 Later foliations and other structures have been developed together with it 

 . . . . ; but the most prominent foliation of the district, and an enormous 

 amount of folding of the same age as this foliation, were already in existence 

 before it, and were folded by it. 



' It is clear then that " the anticline " cannot be a simple or exact anticline 

 of bedding. It should rather be looked on as an anticline of the limbs and 

 axes [Clough means axial planes] of the early folds which affect the 

 bedding. To what extent it departs from being an anticline of bedding must 

 depend on the amount of this early folding.' 



He then proceeds to gauge the effect of the early folding by 

 comparing the outcrops encountered on the two sides of the Cowal 

 Anticline. The contrast is shown to be remarkable, wherefrom he 

 derives the suggestion that 



'there is a great folding of " pre -anticline " age, which, roughly speaking, 

 counterbalances the effect of " the anticline " ' 



(1897, p. 86 & pi. x). An unfortunate vagueness of many of 



^ See also 1922, Report A, par. 6. 



