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PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Feb. 6, 



tinues up the glen for about a mile in nearly vertical beds, striking 

 N. 16°-24° E., with a slight inclination to the south of east. The 

 beds are flaggy and micaceous, and sometimes so pulverulent that 

 they might be called sandstones. They are succeeded by a set of 

 flaggy, very micaceous schists, nearly vertical, sometimes quite so, 

 striking N. 44° E. Here a series of bands of grey crystalline lime- 

 stone occurs, with the lines of stratification well marked, especially 

 where layers of schist 1 to 4 feet broad are intercalated with them. 

 A little higher up the river some dykes of felspathic and hornblendic 

 greenstone occur, striking with the strata N. 34° E. 



The same schists continue up the valley, though greatly obscured 

 by deep drift. They are sometimes talcose, sometimes strongly 

 quartzose, but usually micaceous. At the Bridge of Roy they strike 

 N. 45° E. with a south-easterly dip of from 60°-80°. 



Here again therefore we are presented, along another line of sec- 

 tion, with the same order of superposition. Quartzose strata, cor- 

 responding to the upper quartzose flaggy series of Sutherland and 

 Ross and the upper quartz-rock of Islay, pass up into a set of schists 

 which in their lower part contain calcareous seams, exactly as in 

 Sutherland, Ross, and Islay. 



Loch Leven. — Between the section just described and that of Port 

 Appin above alluded to, there is an excellent transverse exposure of 

 the rocks along the shores of the maritime Loch Leven. In skirting 

 the east side of Loch Eil from Port "William southward, the passage- 

 beds, so to speak, between the quartzose and the schistose series are 

 seen on the road-side much contorted and broken, but with a 

 general northerly strike and easterly dip. As we approach Loch 

 Leven, thick bands of white quartz-rock are seen to occur in the 

 series ; and on reaching the margin of that loch we find the whole 

 plunging sharply to the south-east. A bed of limestone is quarried 

 here, above which lies a thick band of white quartz-rock, and then 

 come the true slates of Ballahulish, which lie on the same horizon 

 with those of Easdale. 



The intercalation of white quartz-rock above the limestone and 

 the general interlacing of the quartzose and the schistose series are 

 facts of great importance. 



On the south side of Loch Leven the same slates are well exposed. 

 In spite of the granite and porphyry masses which here occur, they 

 have a marked north-easterly strike, and where first seen, though 

 nearly vertical, incline towards the south-east. Gradually they be- 

 come vertical; and then, among the great slate- quarries, they take a 

 high westerly dip. They are traversed by a cleavage very inferior 

 to that of Easdale, and apparently in the quarries coincident with 

 the lines of bedding. A little eastward, however, on the side of 

 the high road, beyond an archway, there is a good section of the 

 slates, which dip *6°-10° S. of W.'at 45°. They are traversed by 

 cleavage-planes which dip in nearly the same direction at 75°. These 

 planes cut through alternate beds, the coarser sandy layers being 

 uncleaved. Immediately under the slates comes a thick band of 

 hard blue and grey compact and flinty limestone, with lighter bands 



