94 MR. E. B. BAILEY ON^ THE STETJCTURE OE [vol. Ixxviii, 



attendant slides ; and their liability to secondary folding. The reality of all 

 these geological features is, I consider, unassailable by anyone acquainted with 

 the field-evidence. At the same time, I should like to notice certain important 

 modifications which I have been able to effect as a result of continued 

 enquiry. For instance, the Eilde Flags of the Loch-Eilde Mor outcrop are 

 no longer referred wholly to the upper limb of the Appin Fold (see 1916, 

 figs. 9-10, and 1910 a, pi. xliii) ; while the limestone at Loch Dochard, east of 

 the Etive Granite, is now definitely relegated to a lower structural position 

 than the Appin Core. 



The two changes just mentioned, along with much else of importance, are 

 due to later work by Mr. E. G. Carruthers. Whereas I had already ventured 

 to correlate fiags of two important outcrops, the one running past Loch Eilde 

 Mor, the other through Fort William, I confess that I did not think that 

 these outcrops had any underground connexion in the intervening country 

 (1910 a, p. 616 & pi. xliii) — although I was well aware that my evidence in this 

 matter was inconclusive. Mr. Carruthers was fortunate enough to find that 

 a persistent south-westward pitch causes a remarkable zigzag approach of the 

 Loch-Eilde and Fort- William outcrops in the district beyond that which I 

 had examined, and I now agree with him that an underground connexion is 

 highly probable. As an incident of the zigzag approach just mentioned, 

 Mr. Carruthers noted folding of the Fort-William Slide. I am of opinion — 

 but I admit Mr. Carruthers attaches little weight to my suggestion — that 

 the Meall a' Bhuirich Slide in its type-exposure is merely the folded con- 

 tinuation of the Fort- William Slide. My original view that the Meall-a'- 

 Bhumch Slide reappears east of the Loch-Eilde outcrop (1910 a, h, pi. xlii) I 

 frankly disavow. PL I shows the approach of the two outcrops of Eilde 

 Flags, and, in so far as it is a continuation of my previously published 

 mapping, it is mainly based upon Mr. Carruthers's work ^ — except, of course, 

 that I am alone responsible for the expressed suggestion that the Fort- 

 William and Meall-a'-Bhuirich Slides are one and the same. The correction 

 has two very pleasant features : looking back, one realizes anew that what 

 has proved impossible to iinravel in. some particular region may be an easy 

 matter to disting-uish in an adjoining district ; looking forward, one hopes 

 that some of the remaining elements of doubt may in their turn be dispelled, 

 so soon as opportunity arises for further extension of the field of mapping. 



Mr. Carruthers's other points need not detain us long, since I have no 

 strong opinion in regard to them, and have modelled my present account on 

 non-committal lines. They may be summarized as follows : — 



(1) Mr. Carruthers thinks that he can locally (that is, in the Kinlochleven 

 district) distinguish three mica- schists and three quartzites, intervening 

 between the Ballachulish Limestone and the Eilde Flags — where previously I 

 only had recognized one group of each, namely, the Leven Schists and the 

 Glen-Coe Qnartzite. I have discussed these two alternative interpretations 

 elsewhere (1916, p. 62). Here, in order to avoid uncertainties, I treat the 

 mica-schist and quartzite complex as one great stratigraphical group (PL I), 

 In regard to the structural relations, which this inclusive group bears to the 

 Ballachulish Limestone, on the one hand, and the Eilde Flags, on the other, 

 Mr. Carruthers and I are in very close agreement. I have myself dealt more 

 particularly with the limestone side of the complex, while Mr. Carruthers has 

 gathered much of the information regarding the behaviour of the flags. 



(2) Mr. Carruthers thinks that the rocks shown as belonging to the Sub- 

 Eilde Complex in PL I are stratigraphically distinct from any of their fellows 

 in the neighbourhood. I have already discussed this difficult question (1916, 

 p. 62), and meanwhile do not intend to resuscitate it. In the present paper 

 I merely use the outcrops of these rocks as indicating a lower structural 

 level than is reached in the Loch-Eilde outcrop of the Eilde Flags, without 



^ For permission to publish this material I thank Mr. E. G. Carruthers, as 

 well as the Director of H.M. Geological Survey. 



