671 
of Edinburgh, Session 1877-78. 
Another boulder, a few hundred yards to the south, measured 
(above ground) 18x18x12 feet. 
It deserves notice that the sharpest end of each boulder points in 
the same direction — viz., about S.W. (magn.) — i.e., towards the 
mouth of Loch Creran. 
The terrace on which these boulders lie, is about 290 feet above 
the sea. 
Hall mantioned that, in a higher part of Glen Creran, the 
boulders are more numerous, and some of them larger than the two 
examined. 
All the boulders appeared to be of the same species of rock. Hall, 
who evidently had some practical knowledge of rocks, called it a 
black granite, and affirmed that there was no granite like it in all 
that district. The rocks of the mountain on the opposite, or south 
side, of Loch Creran, rising steeply to a height of above 2000 feet, he 
knew were a grey granite. The Loch Etive granite, about four miles 
to the south, and the Durra granite, about eight miles to the east, 
being of a light grey colour, he had always wondered where these 
dark coloured boulders could have come from. 
The rocks in Loch Creran, and in the hills immediately adjoining, 
are a blue schistose clay slate, with a rapid dip. 
One or two other points may here be noted, communicated by 
Hall ; — 
A small river runs into Loch Creran, at its head, flowing out of a 
small fresh-water lake, which is separated from the sea by a spit of 
gravel and sand, crossing the valley, and cut through by the river. 
The sand, Hall stated, is full of sea-shells, and so is the bed of the 
lake, and even the channel of the river before reaching the lake. In 
this last-mentioned river, the shells are in a bed of fine clay — whitish 
in colour, which is used as a manure for arable land. In fact, it is 
this bed of shell clay which originated the name “ Crer-an,” i.e., 
“ Clay," or “ Chalk River." 
These facts indicate, of course, a period when the sea stood at 
a higher level — to the extent of at least 20 feet, which is about the 
height of the shelly bed above mentioned. When the sea fell to 
its present level, a blockage of drift, now between the sea and 
the lake, caused the lake to be formed, with an overflow by the 
river, which runs out of the lake into the sea. There are several 
