442 
kingdom. The concurrent testimony of all who have ex- 
amined both in situ is, that they are precisely similar. 
In Snowdonia are abundant evidences of some immense 
moving mass having descended each valley, and upon 
this coincidence, strengthened and confirmed by the colla- 
teral evidence of glaciers having formerly been of much 
greater extent than they now are — upon this close analogy 
and general prevalence of the phenomena here described, is 
based the supposition, that glaciers formerly occupied the 
valleys which have been described ; and it is believed that 
further observations, made in the situations and in the 
manner I have alluded to, will furnish incontestible evidence 
of the former existence of glaciers in Great Britain. 
