part 2] SOUTH-WEST HIGHLAI^DS of SCOTLAND. 129 



A}3pin Limestone to the Leven Schists) and, so far as the evidence 

 went, might be purely local adjustments due to the folding of that 

 group. 



Of the Loch- Awe Najope it was difficult to form a clear opinion. 

 The presence of a volcanic group in that district did not necessarily 

 imply that these rocks were not in place, as volcanic eruptions were 

 often localized, and lavas had been found on what the speaker 

 believed to be the same horizon, in Upper Banffshire. The 

 ' Boulder-Bed ' occurs in Islay, in Tay vallich, in Perthshire, in 

 Aberdeenshire, and in Banifshire, always in association with a 

 quartzite, limestone, and black or grey shales, and forms certainly 

 one of the most useful landmarks in the correlation of Highland 

 rocks. In that case the Loch- Awe Series could be traced from 

 Isla}" to Portsoy and the Ballachulish Series from Ardmucknish (or 

 perhaps Easdale) to the shores of the Moray Firth, and the varia- 

 tion was by no means great. It was difficult to understand how in 

 Loch Awe and Ballachulish, despite enormous displacements, the 

 rocks were exactly of the type which occurred in similar positions 

 evervwhere along: the southern eds^e of the Moine Gneiss, 



The Argyllshire nappes were evidently of an entirely different 

 type from their Swiss analogues. The Scottish nappes rested on 

 no marked plane of disturbance ; the}'' have no ' roots ' ; their 

 facies is that of the country in which they are found ; their 

 metamorphism is similar to that of the surrounding rocks ; they 

 are not markedly transgressive ; and they seem to differ in no im- 

 portant respects from autochthonous strata. At present, it was 

 necessary to place them to a suspense account. Nothing would 

 be more welcome to Scottish geologists than the proof that Alpine 

 tectonics were repeated in typical development in the Southern 

 Highlands, but much work had still to be done before that day 

 arrived. 



Mr, H, H. Read said that all workers in the Highlands were 

 greatly indebted to the Author for his application of the wonderful 

 results achieved by Alpine geologists to the solution of Highland 

 problems, but the speaker considered that the major structures of 

 the Highlands, owing to the metamorphosed condition of Scottish 

 rocks, could never be demonstrated with even a small part of that 

 definiteness which characterizes Alpine tectonics. 



It was unfortunate that there was so little correspondence 

 between the metamorphic zones and the structural features of the 

 ground described by the Author, and this, together with the 

 absence of dislocation-metamorphism (not necessarily myloniza- 

 tion), especially in the Loch-Awe region, was, in the speaker's 

 opinion, a somewhat serious objection to the Author's inter- 

 pretation. The Author's suggestion that the presence of carbon 

 in the Ballachulish Slates had prevented the formation of garnet 

 did not apply to the garnetiferous, graphitic, and carbonaceous 

 schists of Banffshire, 



The speaker would welcome some information as to where the 



Q. J, G. S. No. 310. K 



