OP THE OUTER HEBRIDES. 853 



close to the base of the hills. This debris and the large perched 

 blocks no doubt both belong to the time when the mer cle glace was 

 waning, and the hills of South Uist were becoming more and more 

 uncovered. I saw no trace of any small valley-glacier having 

 descended the hills to the west, all the erratics and morainic matter 

 of that region having been laid down, as I believe, when the ice- 

 sheet was melting away. But in the neighbourhood of Beinn- 

 mhor we have evidence of a considerable flow of ice towards the 

 south-east into Lochaoineart. The evidence consists of striations 

 and perched blocks. Due south from the top of Beinn-mhor the 

 lower slopes of the hills facing Lochaoineart are glaciated in the 

 direction of the loch, as indicated upon the map, and a number of 

 large boulders are perched upon the slopes which have evidently 

 been carried down from Beinn-mhor. It is clear, however, from the 

 height reached by these secondary striae and the perched blocks, that 

 it was no ordinary local glacier that passed down the lower reaches 

 of Lochaoineart. It seemed to me that we had here quite the 

 counterpart of what we found in the valley of Loch Lacasdail and in 

 the neighbourhood of the Langa and the Cliseam, a change, namely, 

 in the flow of the ice which was induced during the decrease of the 

 mer cle glace of the Minch. At a greater elevation the hills are 

 distinctly glaciated in the opposite direction, and the well-rounded 

 shoulders of Beinn-mhor itself attest that during the climax of the 

 glacial period the whole region was overflowed from the Minch up 

 to a height of not less than 1600 feet. 



I saw no moraine mounds in the valleys coming down from 

 Beinn-mhor to Lochaoineart. The nature of the ground, indeed, is 

 not such as would favour the formation of local glaciers of any 

 importance. If such ever hung on the southern slope of the 

 mountain they must have been of insignificant size ; for, as I have 

 said, they have left no moraines behind them. I have little doubt, 

 however, that moraines exist to the north in the valleys that come 

 down to the Minch between Beinn-mhor and Heel a, a district which 

 we did not traverse. All that can be inferred from the evidence 

 which came before us is that during the greatest extent of the ice- 

 sheet the flow of the ice was persistently across the whole island 

 from the Minch to the Atlantic, and that when the level of the mer 

 cle glace began to sink, and the hills to be uncovered, local glaciers 

 of considerable size (or small ice-sheets, as they might be termed) 

 flowed down the slopes to coalesce with the waning ice-sheet. 

 Thus a newer set of striae was engraved upon the rock, the trend 

 of which is sometimes nearly at right angles, and at other times runs 

 in quite the opposite direction to the primary glaciation, according 

 as the slope of the ground guided the local ice. 



6. Freshwater Lakes and Sea-lochs. — The freshwater lakes of South 

 Uist are, as far as we saw, restricted to the low grounds, and are of 

 the usual irregular straggling character. Like those of North Uist 

 and Benbecula, they appear to rest partly in rock and partly in till, 

 and to have a tendency to lengthen out in the line of glaciation. 

 No mountain -valley lakes seem to exist, unless it be in the hilly 



