390 Proceedings of the Royal Physical Society. 
It is difficult to determine positively the age of this dyke 
from the strata in this district. If the position of the sand- 
stone on the sides of the Coates Hill tells, as it seems to do, 
that this hill was elevated subsequently to the majority of the 
hills around, then this trap dyke must be either a contempo- 
raneous or subsequent intrusion. 
The Boulder Clay. 
The boulder clay is a light-coloured clay, containing small 
boulders, many of them having the rubbed and polished 
appearance peculiar to and common in this deposit. It covers 
the Gallows Hill. The only section of it that I have seen is 
in a gully in a narrow plantation running down from the Old 
Well road ; but this is of no great depth. It is exposed in the 
Whins, where it is sometimes dug for use in the village. The 
shoulder of land between Moffat and Annan Waters, forming 
Aikrigg farm, seems to consist also of boulder clay. A few 
of the large boulders here lying on the surface are from the 
Trap Dyke, which passes through the fields in this locality, 
although it cannot be detected on the surface. 
Gravely here and there intermingled with sand, occupies 
the bottom of the valleys. At Granton, on the Dykefarm 
and in other localities, it exists in considerable masses. It 
presents no peculiarities requiring particular notice. 
The sides of the hills are covered with angular shivers — 
fragments of the underlying rocks — mixed with soil. 
Peat is abundant in the district. The flat summits of the 
mountains are covered with hill peat formed of, and now form- 
ing from, the mosses, lichens, heather, and rushes which cover 
the hills. It is a friable peat, wanting coherence, and is 
generally intersected by innumerable gashes (moss-hags), 
formed by the draining of the rain-water. The peat in the 
low grounds, as at Lochhouse, contains the trunks of trees of 
species similar to what still grow in the district, — fir, hazel, 
and birch. 
