238 The hish Naturalist. 



the thaw, blocks shot straight over the glacier to one spot, 

 there accumulating the stack that had so often puzzled me 

 when shooting in the glen. In other places in these hills, 

 those of Mayo, Donegal, &c, I have seen similar stacks, but 

 in no places did I verify their formation but in this locality. 



In the Co. Donegal, between the highlands of Kilmacrenan 

 and Boylagh baronies, and the highlands of Barnesmore, that 

 lies between the valleys of the Swilly and Finn, there is a 

 comparatively low country, in which in places I saw stacks of 

 small dimensions. Their origin interested me, and during my 

 residence of some five or six years at Iyetterkennyand Ramelton 

 I found that if there was a fall of snow in the county it was 

 greater in this area than elsewhere, even on the hills, except 

 Knocksnatty, east of Glenties. You could scarcely get from 

 Iyetterkenny to Stranorlar on account of the snow-drifts, 

 while you could drive anywhere through the Northern 

 Highlands. 



Snow-drifts in the Donegal Highlands while I was there were 

 not as marked features of the hills as those in the Co. 

 Wicklow, but there was one large drift to the north-east of 

 Errigal, over which, during the thaw, the quartzite detritus 

 slid, and has formed at its margin a massive esker-like high 

 accumulation of shingle. In this county, between Falcarragh 

 and Gweedore, there is, in the valley through which the road 

 runs, a peculiar ridge of large blocks, which I suspect must be 

 due to a snow-drift under the cliff to the westward ; this, 

 however, I was not able to verify while I was in this county. 



On the flat between this valley and the sea south of the 

 Bloody Foreland, there is an irregular curved line of blocks, 

 or rather there is a tract without blocks, and a tract with 

 blocks ; the blocks becoming more frequent as you approach 

 the curved marginal line. The reason for this was familiar to 

 me — the slope in some years was covered with frozen snow, 

 over which stones from the high ground slide, when the 

 thaw commenced. This I had previously studied in the Cos. 

 Wicklow and Wexford, especially at Ballinsillog, on the slope 

 north-east of Croaghan Kinshallagh, near the boundary of the 

 two counties. When this slope was visited there was scarcely 

 any snow on it, but what had been there had melted and frozen 

 and was a sheet as slippery as glass. Over this stones were 

 sliding, from the size of eggs to over half a hundred-weight, 



