0E THE OUTER HEBRIDES. 833 



preserved. On the northern slopes of Carran and on Beinn Sheile- 

 boist the direction of these is "W. 30° IS". ; on the slopes of Cleite 

 Niseboistit is W.28° N". ; near Borgh Meadhonachit is W. 35°-40° N. ; 

 a little south of Borgh-mor it increases to N.W. ; and in one place, 

 halfway between Borgh-mor and Scarrasta, the trend is N". 15° W. 

 This latter, however, is quite local ; for on the hills immediately 

 south of Scarrasta the glaciation has the normal direction of 

 W. 30° 1ST. 



After leaving the Northside Sands the road to Obbe passes through 

 ruinous roches moutonnees and hummocks of gneiss. Greabhal, the 

 rocky hill immediately to the north, being fully exposed to south- 

 east and south-west, has been subjected to much abrasion. We did 

 not detect any striae, however; but the trend of the roches moutonnees 

 and smoothed faces of rock is unmistakably from south-east to north- 

 west. 



Itoinebhal (1506 feet), the most conspicuous hill in the south of 

 Harris, is smoothed from base to summit; but, owing to the weather- 

 ing of the gneiss, few striated faces have been preserved. We noted 

 striae, however, on the south-west slope of the hill at the height of 

 950 feet or thereabout, and they pointed to W. 30° N. At the 

 summit the rock, which consists of highly hornblendic and granati- 

 ferous gneiss, traversed by basalt dykes, is broken up by frost &c, 

 and the roches moutonnees are hardly recognizable. But, notwith- 

 standing this, one cannot fail to see that the whole contour of the 

 summit, which has a rounded and smoothed-off appearance, differs 

 markedly from the configuration of those rugged mountain-tops that 

 rise to a greater elevation than 1600 feet, as, for example, the Langa 

 and the Cliseam in North Harris, and Hecla and Beinn-mhor in 

 South Uist. Some little distance down from the top of Roinebhal, 

 the roches moutonnees, although broken up, are yet recognizable. 

 While, doubtless, the ruinous aspect of the rounded rocks and the 

 obscurely or faintly marked character of the glaciation at the higher 

 elevations is in large measure due, as before remarked, to the early 

 exposure of the hill-tops to the action of frost, yet we may well be- 

 lieve that the glaciation was never so intense there as at lower levels. 

 A hill-top over which a thickness of 50 or 100 feet of glacier-ice 

 flowed would, other things being equal, be less deeply ground and 

 abraded and fluted than a hill-slope exposed to the pressure of up- 

 wards of 1000 feet of ice. Hence we might well expect to find the 

 marks of glaciation at heights of 1500 or 1600 feet much more 

 evanescent than at lower levels. 



The country immediately to the north of Boinebhal is low-lying, 

 and rises with a somewhat gentle inclination until it abuts upon the 

 hills that trend along the west coast of the island. It is impossible 

 to convey an adequate impression of the barren and desolate aspect 

 of this part of Harris. The ground is rough and rapidly undulating 

 and all but destitute of vegetation, what little grass there is finding 

 a soil for itself only in cracks and crannies of roches moutonnees, 

 which are otherwise so bare and fresh-looking that it needs but 

 little imagination to conjure back the old ice-sheet. Every thing 

 Q.J.G.S. No. 136. 3 k 



