OE THE OUTER HEBRIDES. 851 



Boisdale, and round the coast to Lochaoineart, and were much im- 

 pressed with the appearance of severe glaciation on the seaward 

 faces of the Loch-Boisdale hills. Opposite Staoleidh we landed, and 

 got striae pointing inland about W. 10°-15° K. We landed again 

 on the north shore of Lochaoineart, and crossed over the shoulder of 

 Beinn-mhor, the day unfortunately proving unfavourable for the 

 ascent to the summit, which was shrouded in thick mist. The 

 general or primary glaciation in this neighbourhood is very striking. 

 A number of bearings gave as nearly as possible the same direction, 

 namely N. 35° W., some of the striae being very distinct and others 

 rather faded. The roches moutonnees are wonderfully preserved, and 

 show the direction of glaciation very clearly. But one of the most 

 interesting features noticed here was the evidence of a local or 

 secondary glaciation, which will be described further on. We traced 

 glacial striae up to a height of 1150 feet at least, the direction being, 

 as before mentioned, N. 35° W. These striae did not slope down 

 the hill, but were horizontal. Although thick mist prevented our 

 getting to the top of Beinn-mhor, we yet had an excellent view of 

 the whole hill when we descended to the low ground ; for the mists 

 suddenly cleared off, and left every thing bathed in sunshine. Esti- 

 mating from the highest point we reached, which we could distin- 

 guish quite well from below, the ice-worn moutonnee surface appeared 

 to extend upwards to within 300 or 400 feet of the summit, which 

 is 2033 feet above the sea. The upper non-glaciated part is a 

 sharp, somewhat serrated or ragged ridge, from which long slopes 

 of debris shoot down to the glaciated shoulders of the hill, which 

 they encroach upon and partially obscure. Hecla (1988 feet) is the 

 only other hill in South Uist whose top rises above the limits of the 

 primary or general glaciation. Nothing can be more distinct than 

 the line of demarcation between its sharp, jagged, peaked summit 

 and its rounded, softly outlined shoulders, with their moutonnee sur- 

 face. We saw this mountain under every advantage from the land, 

 and again from the sea at no great distance from the shore, and it 

 always presented the same striking contrast. Unfortunately our time 

 did not permit us to explore it and the hilly region to the north-east. 

 A glance at the accompanying map (PL XXXIII.), on which the 

 principal bearings are inserted, will show a curious change in the 

 direction of the striae about the middle of the island. This change 

 is unquestionably due to the presence of Hecla, Beinn-mhor, and the 

 mountain-masses in their vicinity. The mer de glace flowed against 

 the mountains from a little south of east, and, streaming round the 

 obstruction, gave rise to two sets of striae in its rear, which a 

 reference to the map will show differ in direction from the average 

 or normal trend of the ice-flow in South List. The phenomena are 

 precisely the same as may be witnessed in the bed of any stream 

 containing large boulders. The water, forced aside to right and left 

 by an obstacle in its path, gives rise to two currents, which flow in 

 again from either hand to meet each other at some distance behind 

 the boulder or rock that forms the obstruction. Doubtless could we 

 examine the rocks at the sea-bottom some little distance out from 



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