of Edinburgh, Session 1879-80. 
615 
W.H.W. and E.S.E. The striating agent unquestionably here came 
from the westward. 
2. Loch Over an. — On the east side of this loch there are a number 
of boulders, some of very large size, of which notice was taken in 
the Committee’s two last Reports. 
My attention was drawn to these by our Convener, so that in 
the event of my visiting that district during the past summer I 
might endeavour to discover from what quarter these boulders had 
come. 
I was glad to find myself able to comply with this request, and I 
spent several days in examining the district in question. 
On the hanks of the Creran there are two distinct classes of 
boulders, differing in mineralogical composition. 
Those in the lower part of Glen Creran, near the bridge at the 
head of the loch and between Invercreran House and Easnacloich, 
are much weather-worn, dense in structure, and dark in colour. The 
hornblende in them is dark-brown in colour, with but little felspar, 
and they contain a little bronzy biotite. 
In a higher part of the glen, at and above Easnacloich House, the 
boulders have much felspar, which is pale in colour ; also hornblende 
which is always green, sometimes light-green, and a little quartz, 
hut almost no biotite. 
The rocks of the glen adjoining the places where both sets of 
boulders lie are quite different from the rocks composing the 
boulders • I therefore made a diligent search among the hills in the 
neighbourhood for the parent rocks. 
The first-mentioned set of boulders, which I may call the Inver- 
creran boulders, I found as regards mineral composition to be the 
same, or very nearly the same, as a hand of rock in the Coire 
Dhu of Fraochaid , at a height of from 1500 to 1700 feet above the 
sea. This corry leads up from Glen Creran about 4 or 5 miles to 
the IST.HST.E. of Invercreran. The only mineralogical difference which 
I could detect was, that in the rocks on the hill, there was perhaps 
rather less biotite. 
The place where the rock composing the Easnacloich boulders was 
found is in a col lying a little north of the fountain-tarn of the River 
Durer, a river running into the Linnhe Loch at Coil Bay. The 
col lies between Stab Coire Dhu and Stob Coire Ruadh, at a height 
