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— a system of local subaerial glaciers — are abundant throughout all 

 the alpine grounds of Scotland, as well as those of Cumberland and 

 Wales. By these the boulder clay — the result of the original and 

 general ice-work — has been swept out of many valleys, and ordinary 

 moraine detritus left in its stead in more partial situations. One of 

 the most notable memorials of local glaciers in our island is the 

 curving ridge of detritus forming the dam which retains a mountain 

 lake. Examples are to be seen at Lochs Whoi-ral and Brandy on 

 the eastern skirts of the Grampians, at Loch Skene in Dumfries- 

 shire, and Llyn Idwal in Wales. In many places, a north-looking 

 sinus in a mountain has such a curving ridge of detritus girdling it 

 in front, without any lake. Keeping in view these objects, of which 

 I have now seen a considerable number, I am inclined to think that 

 the valley between Arthur's Seat and Salisbury Crags has been the 

 seat of a glacier, and that its moraine is still to be seen at the lower 

 end, near the bleaching-green. There is certainly at that spot a 

 broad agger of detrital matter, including many rough blocks, and 

 which has all the appearance of having once confined a lake, the breach 

 by which the water was discharged being still visible. That this 

 lake existed so lately as the reign of Mary is tolerably well evidenced 

 by a passage in Marjoribanks' Annals, where it is stated that, at 

 the marriage of Lord Fleming to the daughter of Lord Ross, in May 

 1564, " the banquet was made in the park of Holyrood House, 

 under Arthur's Seat, at the end of the loch, the Queen's grace 

 being present," — this description being scarcely applicable to any 

 other place. It may be considered as favourable to this view of the 

 former condition of the Hunter's Bog, that very £ew blocks lie there, 

 in comparison with the multitudes which are scattered over the moun- 

 tain sides. In other papers I have proved that the system of local 

 and subaerial glaciers was preceded as well as followed by a submer- 

 sion ; fi'om which it may be inferred that it was a period of eleva- 

 tion, — perhaps of such elevation as to bring the higher grounds of 

 our island within the snow-line, — being all that was required to pro- 

 duce the phenomena to be accounted for. 



