118 Proceedings of the Royal Society 
on the meadow was 30 feet in height. (Fig. 5 gives a view of this 
spot.) 
Near the west end of the hill just referred to there was a 
projecting knoll which had apparently intercepted a number of 
boulders. There were about twenty altogether piled on one another, 
and so piled as to indicate that the uppermost could not well have 
obtained its position except by coming from a N.W. direction. 
(Fig. 6 is intended to show this cluster of boulders.) 
Close to this place there was a vein of quartz, which showed a 
smooth surface, sloping down towards the N.W., as if polished by 
some agent which had pressed heavily over it from that direction. 
3. In crossing the island, from Arinagour on the east coast to 
Bein Hock on the west, by the road leading past Arnibost school- 
house, there is a manifest difference in the size and number of the 
boulders. At and near Arinagour the boulders are few in number, 
and small. At and near Arnibost, which is about a mile inland, 
they become numerous, and occupy significant positions, many 
being on smoothed rocks facing the west. 
At Grassipol, and on the sea-coast adjoining Bein Hock hill, 
there are boulders of enormous size. The rock on which most of 
these boulders lie is about 90 feet above the sea, and slopes down 
towards the W.N.W. at an angle of about 10°. It presents a 
surface due apparently to some powerful agency which has levelled 
and smoothed it. Many other examples of this can be seen, close 
to the highroad near the schoolhouse of Arnibost, and particularly 
on the low rocky hills south of the road. 
These smoothed rock surfaces, sloping down towards the north- 
west, are easily distinguishable from the natural surfaces of the rock 
strata. The gneiss rock, especially in this part of the island, is 
seldom in the form of regular beds. Where such occur, the dip is 
not towards the N.W., but towards the S. and S.E. 
At the S.W. end of the island there are several granite boulders 
lying on gneiss rocks. One, which was the largest he saw, attracted 
the Convener’s special attention, lying close to the mansion-house 
of Coll, belonging to Mr Stewart. Its length was 35 feet, its 
width 15 feet, and its height above the surface of the ground 8 
feet. It was leaning on, or at all events pressing against, a mass 
of gneiss rock on its S.E. side. The granite was coarse-grained 
