A HISTORY OF CUMBERLAND 
of the lowering of their outlets by the erosive action of the river, and 
the carrying in of sediments at their upper ends. 
During the phase of glacial action now under consideration, the 
same cause which enlarged and deepened the river valleys also carved 
great grooves upon the surface of the solid rock on the land. Some of 
these grooves, even in Cumberland, are so large as almost to be entitled 
to be called valleys. But as we advance further north into Scotland 
these features increase in size and importance. Even around Kelso, 
for example, the hill-shaded maps of the Ordnance Survey show them in 
great force, sweeping with an undeviating course right across rocks of 
the most diverse composition and age. Near Blairgowrie again, they are 
even more striking ; while in connection with the Highland rocks they 
reach even larger proportions still. 
Another feature of some importance in the scenic geology of Cum- 
berland is represented by the corries or cirques. ‘These are usually 
excavations on the hillsides, shaped like half a bowl or half a funnel. 
Commonly they are characterized by a remarkable regularity of form, 
quite unlike any features produced by the action of any subaerial causes. 
Their origin has given rise to much difference of opinion. The present 
writer, dealing in 1874 especially with those of the Lake district, attri- 
buted their origin’ to the effects of a slow rotatory movement or eddy of 
the ice. There are some very fine examples of these in the valley of the 
Calda, or Caldew, above Carrock Fell; others equally fine, but much larger, 
occur at Melmerby ; while there are few dales in the Lake district that 
do not show some traces of them, usually near the upper part. 
(f) Throughout the greater part of the Glacial Period the move- 
ments of the Cumberland ice were seawards and mainly downhill. But 
while the changes just referred to were in progress, the ice from Gallo- 
way had coalesced with the general stream from the southern uplands 
of Scotland, and had already begun to make a slow advance southwards 
across the Solway—the ice from northern Cumberland extending with 
equal slowness in the opposite direction. The result may be readily con- 
ceived : the opposing streams, after a prolonged contest for mastery, 
eventually became united, and began to send their surplus overflow east- 
ward along the border counties. This is another way of stating the fact 
that a great conjoined scream, formed of both Cumberland and Scottish 
ice, once flowed over the watershed of the Eden and the Tyne, and hence 
seawards by the Tyne valley. On the south of the zone where the 
Cumberland and Scottish streams met end to end, the movement on the 
low ground was mainly southward, and continued thence at least as far as 
North Wales. 
(g) Eventually, the heavy snowfall due to the condensation of the 
aqueous vapour of the Gulf Stream by the uplands of the west of 
Scotland, caused such an increase in the volume of the Scottish ice that 
it overcame the resistance offered by part of the ice from Cumberland, 
thereby bringing its movements around Carlisle to a standstill for a time, 
* Quart. Fourn. Geol. Soc. xxxi. p. 99 ; Geol. Mag., ii. vol. ii. No. x. p. 486. 
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