546 proceedings oe the geological society. [June 25, 



work. But the rock weathers easily, and strise are not easy to find ; 

 all the marks that I found came from the north and west, not from 

 the eastward as I had expected. But the most of these fresh marks 

 are in hollows between hills, where the moving power, if water, had 

 to follow the land, as tides now do in sounds. It seemed to me that 

 sea-ice did the last of the grinding in these regions, and that tides 

 were the moving power when the land was submerged more than 

 it is. 



At Barra Head, on Bernevay, I got marks at 720 feet up, from 

 N.N.W. magnetic, crossing the strike of the rock, on a " tor" near 

 the old fort, close to a cliff whose edge is at the hill-top. A great 

 many travelled blocks are on the island, scattered about the hill-side, 

 at levels higher than the top of Heynish in Tiree, 500 feet. 



Minglay. — The next island north of Bernevay is about three miles 

 long, a mile wide, and a thousand feet high. The west side is a 

 cliff 900 feet high, with a rift cutting into the hills ; it ends in a 

 cave, which is said to reach nearly to the sea on the east coast. 



I stood on one side of the rift, and looked at the opposite wall 

 900 feet high. On the east side from the verge of the cliff the 

 island is a wide valley sloping down to the sea, and to a sandy beach. 

 The inhabitants climb like monkeys, and go wherever there is 

 holding for hands, after eggs and birds. Large loose stones are 

 on the ridge of this island, which is one of the strangest places in 

 these realms. 



I did not land upon the isla nds between Minglay and Castle 

 Bay in Barra ; but I coasted along them, and saw how the waves 

 have dug out whin-dykes, so as to leave long narrow rifts with 

 vertical walls. Through these boats pass in very calm weather. 

 These were " faults," or breaks in the strata ; but they were filled 

 with " dykes ;" for remnants of dykes are left here and there, and 

 make natural bridges, under which boats pass. I walked over one 

 in Minglay, and looked down 550 feet into the sea, and at a bit of 

 the double whin-dyke, which makes this bridge, and another bridge 

 lower down. The rest of the dyke is under water at the bottom of 

 the rift, and the chasm is a bit of marine denudation. 



Barra. — At Castle Bay, in Barra, glacial striae are well preserved 

 at the sea-level, near some boulder-clay. Sept. 24, 1871, 1 took seve- 

 ral rubbings. The direction is from north by west, magnetic, about 

 N.N.W. true. The ice came through a hollow ; on the watershed 

 of the hollow, and on the western coast, and right up to the hill-tops, 

 all the country is glaciated ; and perched blocks are strewn all over 

 the island of Barra. Boulder-clay and drift make the soil. 



South Uist, Sept. 28, 1871. — I drove up the road, and took rubbings 

 from glaciated rocks by the wayside : — 1. At Birsdale, on the wesc 

 side of the hills, in a quarry by the roadside, striae ran from north 

 40° west magnetic, pointing at a gap in the hills. 



2. About halfway up the island, about 100 feet above the sea- 

 level, in the flat country on the west side of the hills, near a large 

 perched block, from north 52° west [magnetic was the direction, 

 and the grooves point at a gap in the chain of hills. 



