36 Mr. J. Bryce's Notices of a late Visit 



and stretching from near Fort William to within 1 J mile of 

 the bridge of Roy, a distance of about 12 miles. Such sub- 

 ordinate elevations are seen at the base of almost every high 

 chain, and mark the axes along which the upheaving forces 

 acted with decreasing intensity. This ridge is separated from 

 the main chain by a slightly depressed tract, having a very 

 smooth outline, into which five glens descending from the Ben 

 Nevis group open at right angles, the surface presenting no 

 marked change of character at the junction. The streams 

 from these glens, as well as those which drain the tract itself, 

 being prevented by the high ground in front from following 

 direct courses to the valley of the Spean, are deflected to the 

 east and west, parallel to the high ground on either side. The 

 watershed of the tract being nearer the western than the east- 

 ern end, and the inclination eastwards slight, there is an im- 

 perfect discharge of the waters, and consequently extensive 

 swamps have been formed, which sometimes become lakes. 

 The annexed sketch will give an idea of the outline of the 

 surface. 



M 



a. Steep slope of the Ben 



Nevis group. 



b. The hollow, or swampy 



tract. 



c. Swelling top of the ridge. 



d. Sides of Oonchan. 



e. River Spean. 



/. Slopes ascending towards 

 Moel-dhu. 



On the western part of the ridge the rock is seen in many 

 places ; and about the middle I found it a little lower than 

 the highest point, c, of the ridge at that part; and I think 

 there can be little doubt that the thickness of the detrital 

 covering is in most places inconsiderable. At its eastern ter- 

 mination detritus appears in more imposing quantity. Near 

 the bridge of Roy the end of the ridge is cut through by 

 numerous streams, or rather the channels of streams; for 

 there is often no water, and the detritus stands out in nume- 

 rous round or elliptic flat-topped mounds with steep sides. 

 Towards the base of Cruachaninish and Benchilinaig these 

 are smaller, and of rounder forms, resembling Danish raths ; 



