﻿598 MR. E. B. BAILEY ON RECUMBENT EOLDS IN THE [NOV. I9IO,. 



and into the grey portion of the limestone on the other; but the 

 latter is only partially seen. 



In the Ballachulish Core the grey and the cream-coloured parts of' 

 the limestone occur together in the great spread of limestone east of 

 Ballachulish ; but in the narrow outcrop extending southwards past 

 Sgorr a' Choise, perhaps continuously, to the Creran River near 

 Salachail, the cream-coloured portion is alone exposed, having beem 

 dissociated from the grey as the result of sliding. This point will,, 

 of course, be dealt with further in the sequel. 



No other group dons so complete a disguise in the hornfels- 

 aureoles as the Ballachulish Limestone. The character most 

 frequently assumed is that of a flaggy, greenish-white calc-silicate 

 hornfels. In all cases, however, save in the isolated outcrops near- 

 the border of the Etive Granite, the altered limestone may be- 

 followed beyond the hornfels zone and its identity established on. 

 the most direct evidence possible. No hesitation, therefore, need 

 be felt in interpreting the outcrops bordering the Etive Granite in. 

 the light of their stratigraphical and structural relations, leaving 

 their special metamorphism out of consideration. 



The most extensive section of calc-silicate hornfels is afforded by 

 the southern slopes of Glen Nevis. This is a section of very great 

 importance in its bearing upon the tectonics of the district ; and it 

 is, therefore, satisfactory to find in it an interlaminated passage-zone 

 developed between the main mass of altered limestone and the- 

 biotite-hornfels which, on the south-east, represents the Leven* 

 Schists. 



(7) The Leven Schists. — The Leven Schists occur with two- 

 facies in the region dealt with. In by far the larger portion of the 

 district, the main mass of the deposit is a homogeneous sandy grey 

 phyllite or mica-schist, with a regular alternation of more and less 

 sandy layers, resulting in a persistent but ill-defined colour-stripe.. 

 Little spangling biotites are very common, while garnets are abun- 

 dant in a few localities, but elsewhere are scarce or altogether 

 absent. Actinolite is also found, though with a far more restricted! 

 occurrence than even the garnets. Hornfelsing produces a hard 

 spotted rock, darker in hue than the grey phyllites, yet at the same 

 time unmistakable. 



Between these phyllites and the Glen Coe Quartzite intervenes. 

 in almost every section a thick transition zone, often called the 

 Banded Series, in which grey phyllites are intercalated with 

 fine-grained quartzite bands and, what is more peculiar, with lead- 

 coloured or black pelitic seams, and often with sandy calcareous 

 beds, a foot or so thick. 



In the other facies, to which reference has been made, the normal 

 grey phyllite is restricted to a moderately thick zone in natural 

 conjunction with the Ballachulish Limestone along the south-east 

 side of the Appin Core ; and beyond this the bulk of the deposit 

 consists of an exaggerated banded series with an enormous develop- 

 ment of quartzose intercalations and black pelitic seams. This 



