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. 



Gravel, 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. 



