A HISTORY OF CUMBERLAND 
could keep pace with, and as a consequence the stream has turned into a 
new channel, leaving its former course on Lazonby Fell as a simple de- 
pression. In two addresses given before the Cumberland and Westmor- 
land Association for the Advancement of Literature and Science, in 1880 
and 1881,’ the present author fully discussed these and some allied 
matters. The papers referred to contained the earliest attempts at dis- 
cussing the origin of any features of the kind above briefly noticed. 
The subject of the evolution of the river valleys is so intimately 
connected with the evolution of the broader features of the scenery that 
no account of the historical geology of the district would be complete 
without some reference to it, and more especially so now that the sub- 
ject in general is attracting so much attention in America and on the 
Continent : furthermore, the evolution of the plains of Cumberland cannot 
be rightly understood until after all the factors concerned in their history 
have been considered, and the rivers are amongst the most important of 
these factors. 
) To the casual observer the broader geological features of Cumber- 
land resolve themselves into (1) the coast-line, (2) two mountain areas 
represented by the Lake district and the upland tract between Brampton 
and Alston, (3) the Carlisle plain. Closer examination makes it evident 
that other features will have to be separately considered. 
The history of the coast-line may be told in a few words: The 
North Channel, the Solway and the Irish Sea are different parts of what 
was, before the Glacial Period, simply the basin of one great river. 
With the submergence that followed the Glacial Period, the sea has been 
admitted all over the area, and up the mouths of the tributary streams; so 
the Solway is merely a drowned river valley. Some modifications of this 
earlier feature have arisen through a partial silting-up of the river mouth, 
and through a trifling amount of waste of the coast-line by the action of 
the sea. Minor details of change have also originated through the rises 
of the land, and the consequent formation of raised beaches. 
(4) The great Cumberland plain is a remnant, now much cut up, 
of what was formerly a great dome, with its higher and central parts 
coincident with the general summit-level of the Lake district. There 
is no better way of grasping the plain-like character of these mountain 
summits as a whole than to study any good relief model of the Lake 
district, such as those exhibited in Keswick. The plain in question is 
regarded by the writer of this article as simply a re-exposed part of the 
very flat and even surface upon which some easily-wasted rocks, possibly 
the Cretaceous rocks, formerly lay. Whatever the rock in question was, it 
was certainly deposited in horizontal layers on a surface shaped out of the 
upturned ends of rocks comprising representatives of all the strata older 
than itself. Subsequently this pile was locally upheaved so as to form a 
low dome coincident with the area of the present Lake district. While 
that upheaval was in progress there, a more abrupt upheaval commenced 
along the north-east side of the great pre-existent zone of fracture, known 
* See Trans. Cumb. and West. Assoc., pt. xiv. p. 73, and pt. xiii. p. 89. 
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