76 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
many cases, beyond their limits. Again, we must not conclude that 
the relative subsidence to which the formation of a lake is imme- 
diately referrible, was contemporaneous with the first formation of the 
fault with which that subsidence is associated. Such a question must 
be decided, not by any such restricted hypothesis, but by the evidence 
afforded by the circumstances of each particular case. 
9. Origin of Valleys.—Though the lakes afford direct evidence of 
the existence of faults, we must not in fact consider them as more 
than the secondary and accidental consequences of the faults with 
which they are associated, the primary effects bemg the valleys in 
which those lakes are situated; for, whatever may have been the ~ 
agency by which the masses once occupying those valleys have been 
removed, it is easy to see that it would act more efficiently along lines 
of great dislocation than elsewhere ; and since the existence of dislo- 
cations along the lake valleys may be considered as established, it 
would seem impossible to avoid the conclusion, that those valleys must 
themselves have originated in such dislocations. We are thus led to 
conclude that a dislocation was produced before the valley began to 
be formed ; that this led to the formation of the valley by denuding 
causes; and that the subsidence which caused the lake was one of 
the last of that series of repeated disturbances which might occur 
during the long interval of time which was probably necessary for the 
completion of the valley. 
10. And here again we are led a step further by the closest ana- 
logy. If the valley of Wastwater originated in a great dislocation, it 
is hardly conceivable that the adjoining valley of Eskdale should not 
have had a similar origin. And again, if the valleys of Troutbeck 
and Kentmere, on the south-eastern side of the district, have been 
caused by dislocations, as shown above, it is difficult to suppose that 
the valley of Long Sleddale should have been formed independently 
of a similar cause. I would observe, however, that this view of the 
origin of valleys of this kind must be considered as applicable princi- 
pally in places nearest the centres or axes of elevation. In other 
cases they may have arisen altogether from aqueous action, or, when 
they origimated im dislocations, they may have had their directions so 
altered, and their character so modified, by denuding causes, as to 
retain no distinct traces of their origin. This obliteration would of 
course be most likely to occur in the parts of a district situated at the 
lower levels, and which must have been longest subjected to the action 
of denuding causes. In such cases valleys may afford very dubious 
indications of the existence or directions of dislocations, and such as 
ought not to be received without evidence of a more positive charac- 
ter. At higher elevations, however, a well-marked and continuous 
valley may frequently afford the strongest presumptive evidence of a 
corresponding disruption. Of such cases in this district, I may in- 
stance, in addition to those already noticed, Borrowdale and Lang- 
dale (both of which extend nearly up to Scaw Fell), and the valley of 
St. John’s, and its continuation through Thirlmere across the centre 
of the district. 
