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one period than it now is ; yet there is also evidence of the 
climate of Great Britain having formerly been much warmer 
than it is at present, of which the fossil trees which form a 
prominent feature in the collection of this society are a 
striking indication. It is probable that various alternations of 
temperature have taken place, and that an attentive examina- 
tion of the evidences afforded by rocks and by their fossil 
contents, may throw much light on this interesting depart- 
ment of oreoloofical science. 
In the valley of the South Esk, Mr. Lyell, in a paper 
read to the Geological Society of London, Dec, 2nd, 1841, 
minutely details a variety of conditions which strongly con- 
firm the supposition, that its lateral mounds were derived 
from glaciers. An enormous mass of boulders on the south- 
em side of Loch Brandy, clearly derived from the precipices 
which overhang the rock on the three other sides, furnishes 
another strong proof of the glacial theory. It is impossible, 
Mr. Lyell observes, to conjecture how the blocks could have 
been transported to their present position, except by means 
of a glacier. Near Loch Worral, also, Mr. Lyell found a 
moraine, extending several hundred yards in width, and 
twenty feet in depth, terminating in a number of hillocks and 
ridges, much resembling in shape some of the terminal 
moraines examined by him in Switzerland. 
A great transverse barrier at Glenairn, resembling an 
artificial dam 200 feet high, and many similar features, are 
detailed at considerable length in the paper alluded to, all of 
them affording evidence of the former existence of glaciers 
in this part of the kingdom. Observations were made in 
Northumberland, Cumberland, and Westmoreland, by Dr. 
Buckland, on his return from Scotland ; and during part of 
that journey I accompanied him from Newcastle to Whitfield, 
thence to Alston Moor, and over the Crossfell ridge of 
mountains into Cumberland. I had thus an opportunity of 
