Vol. 70.] THE BALLACHULISH FOLD NEAB LOCH CKEBAX. 321 



14. The Ballachulish Fold near the Head of Loch Cbeeax 

 (Aegtllshiee). By Edwabd Batteesbx Bailey, B.A., 

 F.G.S. (Read June 10th, 1911.) 



[Plate XLY — Geological Map.] 



The main features o£ the tectonics o£ the Loch Creran district 

 have already been delineated in a paper dealing with a more 

 extended region, and published in 1910 by the Geological Society 

 of London. 1 The results of this earlier work, brought up to date, 

 are epitomized in the map (p. 322), which will serve as an index of 

 the relations of the district to neighbouring portions of Argyllshire 

 and Inverness-shire. 



The original mapping of lower Glen Creran was carried out 

 by. Mr. H. Kynaston and the late Mr. J. S. Grant Wilson. Before 

 preparing the paper just cited, I visited the district on two 

 or three occasions, once accompanying Mr. C. T. Clough, and 

 at another time Mr. H. B. Maufe. Various alterations in the 

 mapping were made as a result of these traverses, and it was 

 found that the more essential structural features were readily 

 determinable in the lio-ht of evidence furnished bv the countrv 

 to the north-east. At the same time, it was apparent from the first 

 that anything like detailed knowledge could only be attained 

 as a result of systematic re-examination, involving a considerable 

 expenditure of time. A favourable opportunity for further work 

 arose officially during the past season, when observations were 

 made which seem worthy of record as an illustration of the 

 complexity locally recognizable in the Highland Schists. 



Two main difficulties are encountered in the field : there are 

 many slides (fold-faults), so many, in fact, that the original strati- 

 graphical sequence has to be accepted from neighbouring districts ; 

 there is also intense contact-alteration, extending for about a mile 

 and three-quarters from the Cruachan Granite, and masking original 

 differences in certain of the rock-groups. 



The following is the stratigraphical sequence ; but, whether it 

 should be read upwards or downwards, is uncertain : — 



9. Eilde Flags and (according 1 to Mr. E. G. Carruthers) other groups. 



8. Glen Coe Quartzite. 



7'. Banded Series. 1 T ~ , . , • 



7. Pelitic Schists. | Leven Schists. 



6. Ballachulish Limestone. 

 5. Ballachulish Slates (black). 



1 E. B. Bailey, ' Kecumbent Folds in the Schists of the Scottish Highlands T 

 Q. J. G. S. vol. Levi, p. 586. 



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