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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Feb. 6, 



east, and the crumpled schists are repeated, until at Glen Lyon the 

 limestone emerges from below them, followed in its turn, as usual, 

 by the quartz-rock. Thus the enormous mass of Ben Lawers, like 

 many other mountains in Scotland, as well as elsewhere, actually 

 occupies a synclinal trough, while the deep valley of Loch Tay, like 

 that of the Great Glen, runs along an anticlinal arch. 



Loch Tay to Loch JRannoch. — The mountainous road from Ken- 

 more, by the north-east flank of Sekiehallien to Loch Eannoch, 

 affords a cross section of the upper schistose beds in their prolonga- 

 tion along the synclinal axis of Leu Lawers, with the limestone 

 below them and the underlying quartz-rock, to perhaps a greater 

 depth than any other locality in the Central Highlands. The north- 

 west dip of the schists continues for some miles beyond Kenmore. 

 At the waterfall close to the road, north of where it crosses the River 

 Lyon, the dip is N. 16° to 30° W. About a mile south of the White- 

 bridge toll-gate the dip changes again to S.E., forming thus the 

 north-western side of the trough. As we proceed, we find the lime- 

 stone rising again in great force from under the schists. It is quar- 

 ried at the end of Loch Kinardochy, where it resembles the Loch 

 Tay limestones, but is greatly contorted. We believe that from this 

 point it ranges across Strath Tummel, and joins the great limestone 

 series of Blair- Atholl, with which it is undoubtedly identical. 

 Following that branch of the road which strikes to the left towards 

 Eannoch, we come to grey micaceous flagstones dipping S. 26° E. at 

 from 55° to nearly 90°. Yeins of a red felspar-porphyry are not 

 unfrequent. About four miles from Loch Eannoch, after passing 

 over a great thickness of quartzo-micaceous flagstones, the road 

 enters a thick zone of limestone, which when first seen is covered 

 by dark silky schists, and has a S.E. dip. It soon rolls over, how- 

 ever, and appears to undulate, often in sharp folds, for a long way, 

 after which the ground becomes obscured by drift until Kinloch 

 Eannoch is reached. 



The section along the north side of the valley eastward from 

 Kinloch Eannoch shows that quartz-rock, sometimes as thick- 

 bedded and brilliantly white as that of Sutherland or of Jura, some- 

 times flaggy and micaceous, underlies the limestone. jSear the inn, 

 the flagstones dip E. at 55°, and are probably intermingled with 

 syenite, large blocks of which strew the hillside. At Drumihastle 

 the limestone occurs again, having crossed the valley of the Eannoch, 

 and it here dips E. 8° N. at 65°. It is flaggy and finely laminated, 

 and is associated with dark schists, as on the south side. Above the 

 limestone, white quartz-rock and flaggy beds supervene. 



The subjoined figure represents the section from Loch Kinar- 

 dochy to Loch Eannoch. It will be seen that the limestone at the 

 former locality lies below schists, and, as we have seen, represents 

 the calcareous bands between the schists and the qiiartzose series on 

 Loch Tay. and indeed throughout the whole Highland region. Be- 

 low this limestone come the usual quartzose strata. These form 

 the higher part of the giant Peak of Schiehallien. But they are here 

 underlain by a thick limestone, and that by another quartz-rock 



