146 Proceedings of the Royal Society 
occurred there on the shore. He, however, saw Mr M‘Farquhar, 
the intelligent ground officer at Barvas, and learnt from him that 
about a mile or more to the west of the mouth of the Barvas 
river, where it flows into the sea, there are rocks which seemed to 
him to have the appearance of sandstone rocks, hut that he was 
not competent to judge of such a matter. 
In these circumstances, the presumption is that the sandstone 
boulder at Garahost came, like all the other boulders in the Lewis, 
from the westward, and not from the mainland of Boss-shire. 
13. The Convener (IX., art. 4) referred to the flatness of the 
district to the south of Stornoway. Between Stornoway and Barvas 
and also both towards Dalbeag and the Butt of Lewis, the island 
presents similar tracts of flatness. The general height above the sea 
is much the same over both districts, viz., from 200 to 300 feet. 
The deposits forming these extensive plains consist of great sheets 
of gravel, sand, and stony clay, — the clay being generally the lowest 
bed. In these flat districts, there is a remarkable scarcity of 
boulders when compared with their number to the south, and these 
few are much below the average size. 
A great many sections of these deposits were examined for sea 
shells ; — hut the only place where shells were seen by the Convener 
was at the brickwork of Garahost above referred to. These shells 
— chiefly the Cardium edule — have long been an object of interest, 
and were examined by the late Dr John Davy of London, as well as 
by Sir Charles W. Thomson and Dr Carpenter. At one time they 
were thought to he arctic ; but the latest opinion is, that they are 
of the type now existing in the adjoining sea. 
Mr James Geikie gives an account of this Garahost deposit in the 
memoir read by him before the London Geological Society in April 
1878. But his account is founded, as he says, chiefly on information 
supplied by Mr Caunter, whose letter he quotes. As the Convener 
made a careful examination of this clay-hed, he gives, with the aid 
of fig. 34, the following description of it: — a, is gneiss rock ; b, is 
coarse shingle ; c, is the bed of clay now worked; and d , is sand 
covering the clay. 
The Convener picked up fragments of the shells from the bed b, 
as also several well-rounded boulders of gneiss, about the size of a 
child’s head. 
