﻿606 MR. E. B. BAILEY ON RECUMBENT FOLDS IN THE [Nov. I9IO, 



slides have been identified, but one of them — the Ballachulish 

 Slide — is especially important. South of the Lairigmor Valley 

 indeed, every section which shows the relations of the Ballachulish 

 Core to the underlying rock-masses shows also the Ballachulish Slide 

 at the base of the core. The effect by which this slide is recognized 

 is the attenuation of a large part of the lower limb of the Balla- 

 chulish Fold, leading in many cases to the total disappearance of 

 one or more recognizable subdivisions. 



The best introduction to the study of slide phenomena is afforded 

 in the district lying between the Lairigmor Valley and Loch Leven. 

 Here it may be observed at once that the Ballachulish Slide certainly 

 developed in the Ballachulish Fold before the latter was bent into 

 the complex secondary syncline lying west of Mam na Gualainn 

 (PI. XLIII, Section D), since, in every section, the western and 

 eastern outcrops of the lower limb of the Ballachulish Fold show 

 precisely analogous phenomena of attenuation. Three groups are 

 affected, to wit : the Leven Schists (7), the Ballachulish Lime- 

 stone (6), and the Ballachulish Slates (5). 



Pig. 4. — Horizontal section showing the relation of the Ballachulish 

 Slide to the Tom Meadhoin fold. 



1 ' MEADHOIN *" fc 



^CHUUS* 



LOCH 

 LEVEN 



SLIDE 



[4=Appin Quartzite ; 5 Ballachulish Slates ; 6= Ballachulish Limestone ; 

 7=Leven Schists; 8=Grlen Coe Quartzite.] 



The attenuation of the Ballachulish Limestone and Slates in 

 connexion with the Ballachulish Slide in this district is especially 

 evident where, for a space of about a couple of miles, the pebbly 

 Appin Quartzite (4) occupies the gape of the fold. Between the 

 outcrop of this quartzite and the Leven Schists on the north-west, 

 the limestone and slates are reduced to a few feet in thickness, 

 except where in certain places they have been entirely (see fig. 4, 

 above) cut out. In striking contrast with this attenuation, the same 

 divisions are strongly developed on the other side of the pebbly 

 quartzite, where they enclose a small outlier of Leven Schists 

 (fig. 4) in the heart of the secondary syncline to which reference 

 has already so often been made. 



