596 
Proceedings of the Royal Society 
had been subjected to some agency which put them into a position 
enabling them to withstand any farther dislocation. 
That this agency came from the north, their position clearly indi- 
cates, an inference confirmed by the transference towards the south 
of the sandstone blocks above mentioned. 
4. On ascending the hills to the west of Corrie, I found smoothed 
surfaces on the sandstone rocks and traces of striae at a height of 
about 158 feet above the sea. The direction of the striae was N.W. 
and S.E. 
On these hills, up to a height of about 587 feet above the sea, the 
boulders are very numerous. All that I examined were of grey 
granite, except three, and these were of conglomerate. 
Between these hills and the high granitic boss to the west, 
reaching to a height of about 1800 feet, there is a valley running 
N. and S. 
The high hill on the other side of the valley to the westward is 
composed of grey granite. I climbed this hill up to a height of 
1270 feet. The ground passed over was thickly strewed with grey 
granite blocks. I could here distinguish two sets of boulders — one 
set angular, which may have fallen from the mountain — another set 
well rounded, which seemed to be erratics, not only because of their 
shape, but because they were of a harder texture than the rock of 
the hill. The ingredient crystals were also larger in size. These 
rounded blocks I observed to be on the hill-side for at least 100 
feet above the point reached by me. 
One of the boulders arrested my attention on account of its size 
and position. It was 25 feet long, 9 feet wide, and 12 feet high. 
This boulder and many others were lying with their longer axis N. 
and S., and could not, as it seemed to me, have fallen from any rocks 
on the hill above. 
5. I went across the island to Loch Ranza, the summit-level being 
about 660 feet above the sea. 
I was unable to examine any individual boulders. But I noticed 
that there were many more on the east side of the summit-level than 
on the west side. 
I saw on the hills facing the N.W. numerous “ perched blocks,” 
at heights of from 1600 to 2000 feet. But they were too far off to 
admit of examination. 
