674 Proceedings of the Poyal Society 
in its farther progress through this kyle or sea channel. One of 
the largest of the boulders is lying with its longer axis N. and S., 
or parallel with the general axis of the 'valley at this point. 
These conditions would be met by the sea standing at a height of 
from 140 to 150 feet above the present level. On both sides of 
the valley here there are horizontal lines traceable at that height, 
as if made by the sea. 
12. Island of Islay . — The Convener, in August 1877, paid a visit 
to this island, for the purpose chiefly of examining the famed raised 
sea beaches on the adjoining island of Jura, and also of inspecting 
some boulders of which notice had been sent to him. 
(1.) On the farm of Lossit, about three miles south of Port Askaig, 
there are four or five boulders of large size. Only two were seen. 
One of these, 13x8x8 feet) is a composite rock containing 
crystals of quartz, augite, and hornblende. The stone is ex- 
tremely hard ; it was with much difficulty that a small specimen 
was detached. The boulder was resting on a bed of bright yellow 
clay, apparently a sediment of deep water. The rocks of the district 
are a slaty schist. On inquiry, it was surmised that rock of a 
similar' kind existed near Kildalton, about 20 miles to the S.E. 
But doubt exists on this point. 
The other boulder, scarcely so large as the foregoing, resembled a 
compact Silurian rock, containing numerous crystals of a whitish 
felspar. 
There was nothing to indicate how or from what quarter these 
boulders came. Their height above the sea was about 300 feet. 
(2.) On the farm of Arnahoo, about three miles north of Port 
Askaig, and 228 feet above the sea, a boulder stands conspicuously 
on the summit of a hill in a position most precarious (fig. 8, 
Plate III.). The rock composing the boulder is a hard porphyry, 
quite different from the rocks of the hill on which it rests. Its 
height above the sea is 228 feet, and the hill itself is about 300 
yards from the sea, towards which it slopes very steeply. 
The boulder is not absolutely on the highest peak of the hill, 
but a few feet below the peak, and on the slope which faces north 
by east (magn.). The only way in which the boulder could 
have stuck on this slope was by its coming right against it, and 
being let down on it gently, i.e., without falling from a height. It 
