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Proceedings of the Royal Society 
of a large size and very white colour, much resembling those found 
in the Arran boulders. Cuffs Hill consists of porphyry. It is 
surrounded by Carboniferous strata. 
7. On a review of the facts stated in these notes regarding the 
Arran boulders, it seems probable that those described had been 
brought from the north, judging by the way in which they lie, and 
also by their composition. 
With reference to the absence of boulders from Brodick Bay, and 
to their abounding along the coast both north and south of that 
bay, what occurred to me was, that if the boulders were brought from 
the north by floating ice, the rocky ridge running down from Goatfell 
peak (a mountain 2874 feet high) to the north point of Brodick 
might have had the effect of diverting the current in a S.E. direction, 
which would carry the ice beyond the bay. That bay is at the 
lower end of a valley which runs up among the highest hills ; and 
if the theory of glacier from these hills be adopted, the bay should 
have been crowded with boulders, instead of being free from 
them. 
Big Cumbrae . — I was guided to the north end of the island 
by the Rev. Mr Lytteil. There, on the farms of Figgatoch and 
Balloch Martin, I found several large boulders of mica schist lying 
on Old Red Sandstone rocks. The largest measured 12x6x3 
feet. But it may have been larger, much of it being below the 
surface of the ground. The longer axis lay N.N.E., which was also 
the direction of the hollow or small valley in which it lay. 
On the 70 feet terrace one of the schist boulders was about 5 feet 
square. 
At the S.W. point of the island (viz., Kennery point), above half 
a mile to the west of Millport, I found several other schist boulders, 
on the old 12 feet sea-terrace. 
Little Cumbrae . — The rocks of this island are entirely a brittle 
claystone trap. The rocks at the highest part (near an old tower), 
at a height of about 400 feet above the sea, are very distinctly 
smoothed and grooved. Most of the smoothed surfaces slope down 
towards and face H. by W. 
The only part of the island on which striae were found is at the 
east side, near a small ruined fortress. A hollow or trench occurs 
between the knoll on which that ruin stands and the main body of 
