166 Proceedings of the Royal Society 
seen at the narrow defile and elsewhere. In the second place, and 
subsequent to that epoch, the whole of the mountains in this 
district underwent submergence beneath the sea, in consequence of 
which not only was the Glencoe valley filled and choked with 
gravel, clay, and sand ; but the highest hills adjoining were under 
water, and subjected to a great sea-current, loaded with ice, which 
flowed from the FT. W. This glacial current brought from hills in 
the west, fragments of rocks from these hills, and dropped them 
in the valley at various points. 
XIV. GAIRLOCH. 
In this district, the hills adjoining the coast present on their west 
slopes, even to their tops, numerous examples of large boulders. 
1. Fig. 40 indicates the hills immediately above the Hotel, with 
coloured dots to represent the boulders on them. 
One of these, the Convener found to be in the position and of 
the dimensions shown in fig. 41. 
Its height above the sea is 675 feet ; but the important feature is 
that it is on the verge of a precipice, which goes sheer down ver- 
tically about 100 feet. The boulder is a coarse-grained reddish 
brown sandstone, entirely different from the rocks of the hills, which 
consist of a slaty schist — being a variety of gneiss. The longer 
axis of the boulder lies N. W. by W. 
There are several other boulders visible along or near to the verge 
of the cliffs, most of them consisting of the same sort of sandstone, 
and some consisting of a reddish granite — all evidently erratics. 
On the lower slopes of these hills, facing the west, there are 
hundreds of similar boulders. They are mostly rounded at the ends, 
and in that respect are quite distinguishable from the rock fragments 
lying also on the hill slopes, which have fallen from the cliffs above. 
2. To the N.E. of Gairloch Hotel there are other perched boulders. 
Fig. 42 shows one of them resting on a small ledge of gneiss rock, 
whose general slope is due west at an angle of about 50°. It rests 
on the rock only at its east end; the west half for about 5 feet does 
not touch the rock of the hill at all. Its height above the sea is 
657 feet. 
This boulder could have been deposited on its narrow site only by 
floating to it from the westward. 
