419 
ON THE EVIDENCE OF THE FORMER EXISTENCE OF GLACIERS 
IN GREAT BRITAIN. BY THOS. SOPWITH, ESQ. F.G.S., 
OF NEWCASTLE. 
Since the visit of Professor Agassiz to the meeting of the 
British Association, which was held at Glasgow, in Sep- 
tember, 1840, a considerable degree of attention has been 
given by geologists to what has been called the Glacial 
Theory, or, in other words, to the study of the phenomena 
of existing Glaciers, and an examination of the reasoning of 
Professor Agassiz and others, by which it has been endea- 
voured to prove that the action of ice, on a scale of enormous 
magnitude, was an important means of effecting many geo- 
logical results, which have hitherto been without any ob- 
vious explanation. This subject has received much attention 
from continental geologists, and has been admirably illus- 
trated by the " Studies of Glaciers," published by Agassiz, 
in 1841 ; several papers have been read at meetings of the 
Geological Society of London ; and the able reports of these, 
and of the proceedings of the British Association, together 
with reviews of Agassiz's work, and the popular character of 
his descriptions, have tended to famiUarise the English public 
with a subject, which, two years ago, was considered in this 
country as a startling novelty. 
The object of the present paper is to present a concise 
view of such leading features of what, for the sake of bre- 
vity, may be conveniently termed the Glacial Theory, as 
may be interesting to those who have not devoted much atten- 
tion to the subject ; to notice the researches which have been 
made with reference to the former existence of glaciers in 
Great Britain, and to point out the means by which further 
evidence can be procured in illustration of this curious and 
interesting subject. 
As many of the papers hitherto read at meetings of this 
Society possess a high practical value, it may perhaps appear 
