of Edinburgh, Session 1880 - 81 . 
263 
land about 250 feet above sea-level. There also a portion of rock 
was discovered, consisting of strata nearly vertical, and ground down 
so as to form a flat surface. The edges of the strata were all 
abraded and smoothed in such a way as to show a passage over 
them of some hard and heavy body from the north. * 
Island op Colonsay. 
1. Notes by Mr William Stevenson , 12 Meadowjield Place , 
Edinburgh . 
(1.) The rocks of the island generally are of a slaty nature, in 
some places curiously bent or twisted. 
There are also places where granite rocks occur, as at and near the 
small boat harbour of Scalasaig, on the east side of the island. 
The rocks inland from the harbour are in a sort of glen, through 
which a road passes. The granite rocks are seen there. 
The walls of the harbour are built of this granite rock. It is of 
a grey colour ; but being somewhat soft in texture, it was faced with 
a yellow-coloured granite brought from Mull in ships. 
(2.) On the west side of the island is Port Mor. It is only a 
bay. Its shores are thickly strewn with boulders of all sizes, up to 
several tons in weight. They are mostly covered with sea- weed. 
* Since this report was written, I have discovered a reference to the 
glaciations of this part of Bute, in a valuable paper by Professor Geikie, £ ‘ On 
the Glacial Drift in Scotland,” in the first volume of the Glasgow Geological 
Society’s Transactions. The following extracts may be given, as confirmatory 
of what is said in the Committee’s report : — 
“A most wonderful exhibition of worn mammilated and striated rocks in 
this part of Scotland, occurs among the slate hills to the north of Loch Fad, 
one of a chain of lakes which nearly cut the Island of Bute into two- The 
hard silurian strata dip at high angles towards the S.E., and present in conse- 
quence their upturned edges towards the ISkW. But instead of forming 
rough-rugged crags, as these rocks when left to themselves tend to do, the 
slates and grits are thrown down into the most perfectly smooth-faced knolls. 
Ths edges of the beds have been planed off obliquely. Moreover, on Barone 
Hill , the top of which is about 520 feet above the sea, the abrasion has been 
done by an agent which came up the steep northern face of that eminence, 
went right over its summit, and pursued its course down into the next valley 
beyond. The striations run from 1ST. 15° W. to 1ST. 20° E. - , 
VOL. XL 
o 
L 
