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Red rocks about its source, and the uneven waste of the Carbon- 
iferous rocks south of Orton Scars, this, the main branch of the 
older Lune, has ceased to be ariver valley. Subaerial denudation, 
acting upon the rocks of the old valley in a manner different from 
- that previously affected by the river, has modified the old features 
more or less ; but not beyond the point of recognition. Looking 
up to Orton Scars from Teba, it requires a good deal to convince 
those not accustomed to such questions, that at one time the river . 
at their feet had its main source above the bare scars of grey 
limestone lying before him. Yet such, I am convinced, was once 
the case. 
The history of the Lune is a complicated one; but is probably 
not more so than that of almost any other river. It merely 
happens in this case that the facts are somewhat more striking 
than usual—and perhaps, also, because the subject has been a 
good deal thought over. 
Attempt to explain the phenomena how one may, there is no 
escaping the conclusion that the Lune must have begun to flow at 
a much higher level than any part of its course occupies at present. 
It is clear also that it must have commenced its course in rocks of 
a very different nature from any that it traverses now. No one 
can doubt, now-a-days, that the Lune has excavated its own channel 
entirely, and has carried it out by the selfsame agencies that it 
employs at the present day. Nor can anyone reasonably doubt 
that its rate of erosion in the past has been, as a rule, much the 
same as it is to-day. The highest rate of erosion we could claim 
for the river certainly does not, and probably never did, much 
exceed a few inches in athousand years. Hence the valley of the 
Lune represents the result of steady, gradual excavation carried on 
_ through untold millions of years. The Lune as a river is older 
than any mountain in either Cumberland or Westmorland, for 
none of the mountains could ever have attained to that distinction 
if there had been no rivers to carve out the depressions that inter- 
- sect the various uplands in so many different directions. 
What is true of the Lune, applies also to most of the other rivers 
of North-western England, and is also true of the Eden. None 
