﻿1861.] 



MUKCniSON AND GEIKIE HIGHLANDS. 



187 



North-west of Scotland. There is no road, and for many miles not 

 even so much as a monntain-traek. Wastes of brown moor and 

 shaking bog ; glens once inhabited but now desolate ; lonely tarns, the 

 haunt of the wild duck and the curlew ; and mountain -ranges that 

 stretch away to the Western Ocean on the one side and the North 

 Sea on the other, and sweep upward among the everlasting mists — 

 such are the features of a region that seems never to have been 

 trodden by foot of geologist. It abounds, nevertheless, with striking 

 and instructive natural sections. In no part of the North-west 

 Highlands can the order of superposition be more distinctly seen 

 than in this wild moimtain-tract between Loch Broom and Loch 

 Maree. 



Crossing Loch Broom at Ullapool, the same rocks are found in the 

 same order, save that the limestone seems not to exist ; nor does it 

 come in again for a long way to the southward. Such disappearances 

 of the calcareous parts of the series are of frequent occurrence 

 throughout the whole of the Scottish Highlands, as in the Silurian 

 formations of England and Wales. The quartz-rock and Cambrian 

 sandstones sweep over the hilly ground of Ben-nam-Ban, and descend 

 into the valley at the head of Little Loch Broom, near the Mansion 

 of Dundonald. Prom this point they were traced by one of us south- 

 ward, up the gorge of Corry Hourachan. Here there is a clear section, 

 which is represented in the accompanying woodcut (fig. 6). 



Fig. 6. — Section at Corry Hourachan, South-west side of 

 Little Loch Broom. 



b. Cambrian sandstone and conglomerate. 



c. Quartz-rock. d. Gneissose schists. 



The stream has cut a deep channel, partly in the line of junction 

 of the quartz-rock and schistose series, and partly transverse to it, 

 the completest possible sections being thus exhibited. At its lower 

 part the stream runs on quartz-rock ; but higher up it is crossed by 

 this rock, which then forms the western side of the ravine, the upper 

 schists being peeled off and left as a cliff on the east side. A short 

 way above this the schists too cross, and sweep up the western side 

 of the valley. The quartz-rock ascends for a short way along the 



