﻿Vol. 66.] SCHISTS OF THE SCOTTISH HIGHLANDS. 599 



peculiar facies is limited, within the region described, to a district 

 bounded on the north by the Ballachulish Granite, on the west by 

 the Appin Core, on the east by the Ballachulish Slide and the Etive 

 Granite, and on the south by the edge of the map. The change 

 does not come in suddenly, for in the road and railway-cuttings, 

 along the shore of Loch Leven north-east of the Ballachulish 

 Granite, there is already an unusual number of black seams. 

 Moreover, the new characters are not strongly marked at first to 

 the south of the granite, although they become more pronounced 

 in this direction, until across Loch Creran they have so far deve- 

 loped that they would render correlation between the Leven and 

 Creran districts impossible, were it not for the chain of intermediate 

 exposures. In this southern region some of the black pelitic seams 

 develop into definite beds of black slate, and some of the quartzose 

 bands into regular pebbly quartzite ; at the same time, thin beds of 

 dark-grey limestone make their appearance. 



(8) The Glen Coe Quartzite is a thick, fine-grained quarfzite, 

 nou-felspathic as a rule, and free from mica. It is well bedded, 

 -and often false-bedded too. In some portions there appears to be a 

 deficiency of siliceous cement, and the rock is then grey ; more 

 often, however, the quartzite is very white. The fine-grained 

 character of this rock distinguishes it from the pebbly Appin 

 Quartzite (4) described above. 



(9) The Eilde Flags are gneissose quartzo-felspathic flag- 

 stones, rich in biotite and muscovite. Their great feature is their 

 evenly-bedded structure, shown by the constant alternation of more 

 and less micaceous layers. In the Fort William district this flag- 

 stone series is much less altered than in the type outcrop running 

 past Loch Eilde Mor. 



Pebbles are rare in the Eilde group, but Mr. Wright has recog- 

 nized a quartzose pebbly zone near the western border of the Eilde 

 outcrop. This zone contains large pebbles of quartz and felspar, 

 and is well exposed on the two sides of the River Leven. The 

 pebbly beds have a quartzose matrix, and, generally speaking, the 

 flags in contact with the Glen Coe Quartzite in this neighbourhood 

 -are all markedly quartzose. The same feature re-appears in the 

 Spean section, where the fine-grained quartzite, underlying the 

 Appin Eold and correlated with the Glen Coe Quartzite, seems to 

 merge into the flagstone series on the north-west. Here, again, 

 pebbles of red felspar have been found in the quartzose beds near 

 the junction, but they are not prominent. 



In the Spean, away from the actual junction with the quartzite, 

 there is a belt of flags with rather more pelitic material than is 

 usual in the Eilde group. This belt continues to run south-south- 

 westwards, alongside of the Fort "William Slide, after the disap- 

 pearance of the Glen Coe Quartzite, and finally goes out to sea west 

 of Onich. In Fort William itself some beds of hard black schist 

 occur in the flags — apparently as an integral portion of the group. 



