376 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



quite obliterated, and new lines of foliation or cleavage super- 

 induced. The rocks are not equally metamorphosed over the 

 whole area. The greatest amount of alteration occurs in the 

 region near the mouth of Loch Fyne, between Sgat Mohr and 

 Caisteal Aoidhe on the east side, and in the corresponding tract on 

 the Kintyre coast to the south-east of Loch Tarbert. Stretching 

 away to the north-east, by the heads of Loch Riddon, Loch 

 Striven, and Loch Goil, is a belt in which the maximum of meta- 

 morphism is shown, on each side of what is called the axis of 

 the "anticline of foliation." This anticlinal axis is that 

 mentioned in the report of the Society's excursion, on 25th June, 

 1898, to Loch Long side, wherein it was stated that the strata at 

 the point where it passes are more altered and twisted than those 

 to the north and to the south. It is an " anticline of foliation," 

 not strictly one of bedding, but rather one "of the early folds 

 that affect the bedding." Before it was formed, the strata had 

 already, by earth movements, been greatly folded, crumpled, and 

 foliated. Those nearer its centre have apparently been covered 

 by a greater thickness of overlying strata, and been subjected to 

 a greater heat than have those farther away. Therefore, as we 

 recede from the centre towards the south-east and towards the 

 north-west, the rocks are less altered. Continued earth movements 

 have afterwards arched up the strata along the line indicated, pro- 

 ducing new curvings and foliations. Subsequent denudation has 

 worn off an immense thickness of material, so that the strata 

 along the line of anticline do not show at the surface as a ridge 

 elevated above those on its flanks. In fact, anticlines of ancient 

 date do not usually rise into ridges, but rather tend to be hollowed 

 into valleys, as the weakest part of folded strata runs along this 

 line, the rocks there having been strained and stretched, while at 

 the bottom of a syncline they have been compressed. A good 

 example of such a formation was seen at the Society's excursion 

 to Killin on 19th April, 1897, when it was pointed out that the 

 valley occupied by Glen Dochart and Loch Tay had been hollowed 

 out of an anticlinal arch. 



The axis of the anticline in Cowal runs parallel to the great 

 boundary fault which crosses the country in a north-east and 

 south-west direction, cutting off the older Highland rocks to 

 the north-west from the newer Lowland rocks to the south-east. 



