﻿1861.] 



MTJRCHISON AND GEIKIE — HIGHLANDS. 



171 



Febbtjary 6, 1861. 



William Rutherford Ancram, Esq., 75 Inverness Terrace, Ken- 

 sington Gardens, and Thomas William Jeffock, Esq., C.E., Woodside, 

 Sheffield, were elected Fellows. 



The following communication was read : — 



On the Altered Rocks of the Western Islands oe Scotland, and 

 the North-western and Central Highlands. By Sir Roderick 

 I. Mttrchison, D.C.L., Y.P.G.S., F.R.S., &c, and Archibald 

 Geikle, Esq., F.R.S.E., F.G.S. 



Contents. 



Introduction. 



§ L Laurentian Gneiss of the Hebri- 

 des and North-western Highlands. 



1. Lewis and Harris. 



r Lewis. 



2. Cambrian Conglomerate of the 



3. Laurentian Gneiss of the main- 



land. 



§ II. Cambrian Sandstone and Con- 

 glomerate of Boss-shire. 



§ III. Succession of Lower Silurian 

 Quartz-rocks, Limestones, and 

 Schists. 



1. Sutherland to the Isle of Skye. 

 Craig-an-Knochan. 

 Drumdrynie. Strath Kennort. 

 Loch Auchall. Loch Broom. 

 From Loch Broom to Loch Maree. 

 Loch Maree. 



Loch Maree to Loch Torridon. 

 The " Grey Heads." Loch Carron. 

 Loch-alsh. Loch Duich. Skye. 



2. Structure of the country between 



the Atlantic and the Line of the 



Great Glen or Caledonian Canal. 

 Loch Broom to Contin. 

 Loch Hourn by Loch Quoich to 



the Caledonian Canal. 

 Arisaig to Banavie. 



Introduction. — In former memoirs upon the crystalline rocks of 

 the north of Scotland, read before this Society, it was shown by one 

 of us, that in the county of Sutherland, in addition to the existence 

 of a fundamental gneiss and an unconformably superposed Cambrian 

 sandstone, there is a conformable ascending series, from certain 

 Lower Silurian quartz-rocks and limestones, up into a group of mi- 

 caceous and gneissose schists. It was also pointed out, in a general 

 sketch-map of the Highlands*, that the order thus observable in 



* In perusing this Memoir, the reader is referred to the geological sketch-map of 

 the Highlands previously published in Quart. Journ . Geol. Soc. vol. xv. pi. 1 2. That 

 map, suggestive of that geological order in the Southern Highlands which we have 

 since worked out, will speedily be followed by a general sketch-map of all Scotland, 

 with illustrative coloured sections, in which the correlation of the stratified rocks 

 of the Highlands with those of much less altered characters in the South of Scotland, 

 and con taming Silurian remains, will be for the first time explained by ourselves. 



3. Eepetition of the Lower Silurian 

 Quartz-rocks, Limestones, and 

 Schists east of the Line of the 

 Great Glen. 

 Line of Great Glen or Caledonian 



Canal. Islay and Jura. 

 Prolongation of the Islay and Jura 



Rocks up Linnhe Loch. 

 Eastern shore of Linnhe Loch. 

 Glen Spean. Loch Lcven. 

 Glen Coe. 



The Breadalbane Deer-Forest. 

 Black Mount by Glen Orchy to 



Loch Awe. 

 Black Mount to Tyndrum. 

 Tyndrum to Loch Tay. 

 Loch Tay. 



Loch Tay to Glen Lyon. 

 Taymouth to Loch Eannoch and 



Dalnacardoch. 

 Dalnacardoch to Blair. 

 Blair-Athol and Glen Tilt. 

 Blair to Dunkeld. 

 Spittal of Glenshee to Dunkeld. 

 Eastern Flanks of the Grampians. 

 § IV. Conclusion. 

 § V. Appendix. 



