1856.] NICOL — QUARTZITES, ETC. OF N.W. SCOTLAND. 



27 



of Dr. MaccuUoch, who, in his * Western Isles,' described it, and 

 gave a section, in which however the gneiss of Rispond is represented 

 as conformable to the quartzite and limestone. Professor Sedgwick 

 and Sir R. Murchison in 1828, and the latter again in 1855, when 

 we examined the section in company, and Mr. Cunningham in 1839, 

 have all come to the same conclusion. It must also be observed, 

 that the superiority of the gneiss to the Umestone is not seen in one 

 place only, or in sections of a few yards' extent, but along the whole 

 escarpment, from the sea-worn precipices of Whiten Head* to the 

 picturesque Craig-na-Feulin, at the extremity of Loch Eriboll, a 

 distance of more than ten miles in a straight line. 



In this line of traverse there is one fact of considerable importance : 

 the red sandstone which on the west side of the Kyle underlies the 

 quartzite, and becomes far thicker and more extensive in the Parph 

 Hills to the west, does not reappear on the east side of Durness or 

 on Loch Eriboll. The quartzite there rests immediately on gneiss, 

 the red sandstone having thinned out. To this remarkable feature 

 we shall have again to refer in noticing the sections further south. 



Sections in the Southern part of the District. — Returning from 

 the extreme north, I shall now describe some sections in the range 

 of the red sandstone and quartzite in the country south of Loch 

 Broom. The interior of Loch Greinord is all coloured as gneiss by 

 MaccuUoch, but consists partly of true gneiss, partly of a singular 

 dark or light green rock, which appeared to me rather a serpentine 

 or syenite, enclosing large angular fragments of gneiss. It forms 

 a group of round-topped conical hills, with smooth, bald summits, 

 destitute of all vegetation, which, though of no great altitude, have 

 yet a remarkably wild and rugged aspect. From this place the 

 gneiss appears to extend, in many peculiar varieties, continuously 

 across the foot of Loch Maree to the Gairloch. Red sandstone, 

 however, forms the outer headlands, and is well exposed on the 

 shore of Loch Greinord, towards the Rumor, dipping at high angles, 

 and covered unconformably by beds of a newer red sandstone f. At 

 Gairloch and on Loch Maree the sandstone is well seen, and its rela- 

 tions, both to the inferior gneiss and to the quartzite, are very distinct, 

 as shown in the accompanying section, fig. 5. The lowest rock is 



Fig. 5. — Section across Gairloch and Loch Maree. 



Loch 3Iaree Hills. 



' * » 



Gairloch. 



W. 



Talladale. 



Ben Eay. 



a. Gneiss (lower). 



b. Red Sandstone. 



c. Quartzite. 



* I did not visit Whiten Head, but both Dr. Macculloch and Mr. Cunningham 

 mention the section. 



t According to Macculloch, the only undoubted New Red Sandstone in Scot- 

 land. — Memoir on Map, p. 94. 



