123 
of Edinburgh, Session 1878 - 79 . 
The gniess of Ben Erival, and of the other adjoining rocky knolls, 
is more close-grained in composition. 
On fig. 9 there is a ground plan, from memory, showing 
the position of the boulder in relation to adjoining hills. Ben 
More, which reaches a height of 330 feet above the sea, and is about 
a mile to the north, is covered with thick beds of sand and fine 
gravel, full of cockle and other sea shells. 
It is also worthy of notice that at present, the bay, immediately 
to the north of Ben Erival, has in it an immense bed of living 
cockles — so immense that it is found profitable to gather them from 
time to time, and send them to Glasgow for sale. 
There is something therefore in the sea or the sea-bottom in this 
district, which now as formerly favours the growth of the Cardium 
edule. 
That this u Big Rock of the Glen ” forms a veritable boulder, and 
that, when it was brought to the spot which it now occupies, it was 
deposited on what was then a submarine bank, not much doubt can 
be entertained.* The boulder must therefore have been floated to 
the spot where it now lies — but from what quarter % Erom the S., 
S.E., or S.W., come it could not; — as Ben Erival, on whose north 
flank it rests, and which ranges for about two miles east and west, 
precludes that idea. There being open sea to the H.W. and IST.E., 
from either of these quarters it might have come, but from no other. 
The plan on fig. 9 explains more clearly how the boulder might 
have been floated from these quarters, and been intercepted in its 
further progress to the south by Ben Erival. 
An examination of the numerous smaller boulders in this district, 
also indicated transportation from some point between west and 
north. The following are cases : — 
1. To the west of the big boulder, and about 100 yards distant, 
there is a small but steep rocky knoll (fig. 9, letter b) whose top 
reaches to a height of 255 feet above the sea, and which is covered 
with boulders, especially on the H.W. 
On a minute study of the relative positions of the boulders on this 
* The submarine character of the bank does not depend solely on the 
presence in it of sea-shells, for they might have been blown up from the 
existing sea-shore by storms. But the materials forming the bank being 
found, by digging under the boulder, to consist of sand and gravel, they 
afford the strongest evidence of a submarine origin. 
