Vol. 69.] LOCH AWE SYNCLINE (ARGYLLSHIRE). 281 



There followed a long interval during which very little was done; 

 hut at last, in a paper read in 1860, the late Mr. Jamieson [2] 

 •demonstrated the truly igneous nature of many of the schists. As 

 a matter of fact, their porphyritic and other igneous structures are 

 frequently preserved in great perfection ; in other instances, however, 

 careful comparison and examination are necessary hefore a confident 

 opinion as to their nature can be entertained. Mr. Jamieson called 

 all these igneous rocks ' greenstones ' ; but the term ' epidiorite ' has 

 been so commonly applied to them since, that it will be used in the 

 sequel. He gave an excellent account of the various sedimentary 

 schists which accompany the epidiorites. He also advanced the view 

 that the structure of the district is synclinal ; but, when we look 

 into the matter, we find that he had nothing to go upon save the 

 inward inclination of the strata, and this, considering that isoclinal 

 folding is prevalent, is not in itself a sufficient criterion. 



In 1885 Mr. J. B. Hill began mapping the district for the 

 Geological Survey, and by degrees brought order out of chaos. 

 Half of the area included in the appended map (PI. XXXII) has 

 been surveyed by him, and the results obtained have been fully set 

 forth in the maps and memoirs of the Survey and in papers com- 

 municated to this Society. "We may notice especially a paper [7] 

 published in 1899, which incidentally presents his position in regard 

 to both structure and succession. His two main achievements are, 

 I think, the recognition of the Loch Awe Syncline and the separation 

 of the sedimentary complex of the district into two divisions : — the 

 Loch Awe Group and the Ardrishaig Phyllites. It is true that he 

 never vouchsafes a clear statement as to how the existence of the 

 Loch Awe Syncline can be demonstrated ; but, for the following 

 two reasons, it seems mere justice to accord to him the credit 

 of the discovery : — 



1. It was Mr. Hill who first correlated the Craignish Phyllites, ou the 

 north-west side of the Loch Awe outcrop, with the Ardrishaig Phyllites 

 on the south-east. 



2. It was he, again, who mapped the Ardrishaig Phyllites across the 

 general strike of the Loch Awe Group, at the northern end of the 

 loch: where, once the mapping has been accomplished, the superposition 

 of the Loch Awe Group upon the Ardrishaig Phyllites may be quite well 

 described as self-evident. 



Although Mr. Hill did the lion's share of the work, he had many 

 collaborators as time went on. In the nineties Mr. C. T. Clough 

 mapped the greater portion of the Ardrishaig Phyllite outcrop 

 in Cowal, on the south-east side of Loch Pyne. About the same 

 time the late Mr. B,. G. Symes entered the district from the north- 

 west, and became responsible for a limited area in the neighbour- 

 hood of Loch Avich. In 1895 Mr. H. Kynaston joined the ranks 

 of the investigators, and surveyed a considerable portion of the 

 district near the northern end of Loch Awe, especially that part 

 which lies on the western side of the loch. His work was brought 

 to a close when he went to the Transvaal in the spring of 1903. 

 Meanwhile Mr. Hill's active co-operation had well-nigh ceased : 



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