176 
Proceedings of the Royal Society 
New Phil. Journal” for 1846) show that in different parts 
of the island there are boulders and smoothed rocks well deserving of 
careful study. 
After what Principal Forbes said about the existence of smoothed 
rocks, and of grooves or striae on these rocks (which he unhesitat- 
ingly ascribed to glacier action), it is impossible to dispute that on 
this island, small as it is, there must have been ice enough in the 
different corries to form glaciers. Perhaps there would be less 
difficulty in adopting the theory, were it supposed that Skye had 
stood much higher out of the sea at the time when these effects were 
produced. 
Principal Forbes in his paper, among other effects ascribed by him 
to the Skye glaciers, speaks of “ the occurrence of large angular de- 
tached masses of hypersthene rock poised upon others , or fantasti- 
cally balanced on the insulated tops of the elliptical domes of rock ” 
(page 92). He also, on this point, quotes Dr Macculloch, who 
supposed that these detached masses were merely fragments which had 
fallen from adjoining hills. But he admits that “ the mode in 
which these fragments lie is remarkable. The bottom of the valley 
is covered with rocky eminences, of which the summits are not only 
bare, but often very narrow, while their declivities are steep and 
sometimes perpendicular. Upon these rocks the fragments lie, and 
in positions so extraordinary, that it is scarcely possible to conceive 
how they have risen so high after the rebound, or how they have 
remained balanced on the very verge of a precipice. One weighing 
about 10 tons has become a rocking stone. Another of not less than 
50 tons stands on the narrow edge of a rock 100 feet higher than 
the ground below, which must first have met it in the descent ” 
(“ Western Islands,” vol. i. p. 388). 
One of these boulders, perched 4 ‘on the narrow edge of a rock,” 
was noticed by the Convener near where the boat takes passengers 
ashore at the head of Loch Scavaig. Fig. 48 represents this 
boulder — a shows its position relative to Lake Coruisk and the sea ; 
b shows its position more exactly on the rock where it stands. 
Dr Macculloch’s idea of the boulder having fallen from an 
adjoining cliff, and rebounded on to the top of the rock where it 
stands, of course cannot be entertained. 
On the other hand, if the boulder was brought by a glacier from 
