147 
of Edinburgh, Session 1878-79. 
The manager of the brickwork pointed out how the upper part 
of the clay-bed appeared to have been scooped out in some parts ; 
the hollow thus made being filled with sand and mud. The bottom 
of the clay-bed was not sufficiently exposed when the Convener 
visited the place, so as to show the bed of shingle ; but there was 
a heap of coarse gravel near the work, which the manager stated 
had come from the bottom of the clay -bed. The Convener had also 
explained to him the vegetable remains said to have been found in 
the upper part of the clay, to which Mr Geikie alludes, as supposed 
by Mr Caunter to have been “ common sea tangle ; ” but of this the 
Convener saw no specimen. 
Mr Geikie mentions that the clay-bed at Garabost is “in all pro- 
bability of the same, or approximately the same, age as the similar 
beds in the north of the island” ( Lond . Geol. Soc. Quarterly 
Journal , vol. xxxiv. p. 827). 
The Convener made an attempt to reach the north of the island, 
to see those shelly clay-beds referred to by Mr Geikie ; but, from 
want of time, he failed to get so far north. He therefore may 
be permitted to refer to Mr Geikie’s account of these beds, and 
to quote one or two passages: 
“ At Port of Hess the boulder clay contains patches of sand. 
But the most remarkable feature is the presence of broken arctic 
and boreal shells , which occur in an irregular manner through the 
mass. The upper surface of the boulder clay is denuded; a 
character better shown in fig. 37, which is taken from the same 
locality. The stratified beds contain shells , most of which are in a 
fragmentary state, but some perfect specimens may be detected. 
They belong to arctic and northern species.” Another place is 
mentioned where “ the beds consist of an upper series of sand 
and gravel deposits, more or less separated from an underlying 
deposit of imperfectly laminated dark blue and grey clay, and silt 
or mud. Shells occur in both.” (“ Great Ice Age,” 2d edition, 
P . 170.) 
These shelly beds of boulder clay, according to Mr Geikie, extend 
over a considerable tract in the north of Lewis. He states, p. 183, 
“ The shelly tills in the sea cliffs near the Butt stretch across the 
island from shore to shore , a distance of two miles or thereabout, 
forming a narrow belt of low ground, which does not rise more 
