634 Proceedings of the Royal Society 
such variation in Uist, and on a larger scale among the hills at Glen 
Creran ; and the boulders in Nairn and Morayshire have evidently 
been brought by currents which came from different points. 
If in the North of Scotland, the normal direction of the current 
was to the S.E., it is probable that the deep trench of the Great 
Caledonian Valley running about E. by N, with a range of hills on 
each side 2000 feet high, would there cause a deviation in the 
direction of the current. As the sea subsided from one level to 
another, the currents would change in directions. 
Examples were seen by me last year in the Lewis, of a change 
even on the same hill. At the top, the direction was as usual N.W., 
near the bottom, it was from due W. or W.S.W. 
Among the hills south of Loch Awe, I found a large boulder 
perched on a peak of rock in a remarkably precarious position. It is 
shown on the diagram. By a glacier it certainly could not have 
been brought, there being neither hills nor valleys to form a glacier. 
If it came by floating ice, the ice might be arrested by the peak, and 
when it melted, the block which the ice carried, might remain. 
7. The largest boulder which I have yet seen, was found by me 
on the west coast of Argyle, in Loch Killasport. Calculating by its 
cubical contents, it weighed about 2770 tons. This boulder, and 
many others of large size, were on the sea shore, and half a mile at 
least from any sea cliff, old or recent. I felt convinced from their 
situation, and also from the direction of their longer axis, that they 
had all come across the sea from the N.W. 
8. A short time ago, my attention was called to a boulder, 
9x8x6 feet, in Roxburghshire, weighing about 1 6 tons. On 
examining it, I found that it was of exactly the same rock as that 
which composes the Penielheugh, the hill on which the Waterloo 
Pillar stands. It is about a mile to the east of the hill, and has 
evidently been floated to its present position by ice. The hill also 
presents other facts of no small interest bearing on the transport of 
boulders. The west side of the hill has been swept bare, so that 
the trap rocks stand out like the bones of a skeleton with the 
skin and flesh off, whilst the east side of the hill is covered by 
soft Old Red Sandstone, as well as by sand and gravel. This place 
affords undoubted evidence of sea with floating ice, which stripped 
the hill and carried fragments to the eastward. 
