﻿590 MR. E. B. BAILEY ON RECUMBENT EOLBS IN THE [NoY. I9IO, 



I may now attempt to indicate, to some extent, my indebtedness 

 to my colleagues. 



The late Mr. Grant Wilson mapped much of the western portion 

 of the district described. In so doing he separated several of the 

 various lithological subdivisions referred to later, establishing 

 among other points the existence of two distinct limestones [22]. 

 He [23] also gave an account of the puzzling metamorphism which 

 the schists undergo in the neighbourhood of the granite masses of 

 the district, and, in addition to this, he drew attention to the 

 remarkably fine folding of the auartzite exposed in Stob Ban near 

 Glen Nevis [24] ; see PL XLIII, Section C. 



Mr. Wilson's work marked a very important advance, but one 

 cannot pass unnoticed the results previously obtained by Macculloch. 

 This great pioneer [25] of Scottish geology had already indicated 

 the approximate positions of several outcrops of ' quartz-rock ' 

 ' mica-slate,' ' clay-slate,' and ' primary limestone ' in the district 

 under consideration. He had also given a detailed account of the 

 transition zone linking the quartzite (Appin Quartzite) and slates 

 (Ballachulish Slates) of the Ballachulish exposures. This transition 

 zone consists, as Macculloch [26] states, of 



' fine sandstones .... striped in endless alternations by black clay .... 

 These belong to that quartz rock which alternates with clay slate, and show 

 the transitions between these two substances.' 



This observation of Macculloch was forgotten for a time, when 

 other considerations led to the view that the quartzite of the 

 Ballachulish sections rests unconformably upon the black slates ; 

 of late years, however, the reality of the passage-zone which he 

 described has been fully confirmed. It was Macculloch, too, who 

 first recorded the contact-alteration of the schists at the margin 

 of the Ballachulish Granite [27]. 



But, to return to the recent work of the Geological Survey : 

 Mr. Wright mapped a considerable tract of the region lying north- 

 east of Kinlochleven, which affords in Binnein Mor especially clear 

 examples of minor folding (Section B, PI. XLIII). He also fixed 

 the position of the line drawn between the Eilde Flags and the 

 Glen Coe Quartzite near Kinlochleven (PL XLII), and found a 

 pebbly horizon close to the junction of these two groups. 



Mr. Anderson has continued Mr. Wright's mapping, and has 

 traced the northward extension of the Leven Schist outcrop shown 

 as Qi) on the map, where it assumes a much more complex form 

 than in the district farther south. 



At an earlier date, Mr. Clough mapped a small part of the Glen 

 Etive district. He also detected the two fold-faults bounding the 

 Sgorr a' Choise fold (PL XLII), and introduced me to the sections 

 which had been mapped by Mr. Wilson in Glen Creran. During a 

 joint excursion [28] into districts bordering the map upon which 

 we were primarily engaged, Mr. Clough detected the true nature 

 of the Loch Dochard limestone and mapped the Allt Coire an Easain 

 section. 



