80 
It would be obvious, from a consideration of these facts, that a 
watershed formed of rocks wasting at the rate of one foot in a 
thousand years could not maintain its position if the rivers flowing 
from it traversed likewise strata whose average rate of removal 
amounted to only about half that quantity. A stream flowing from 
Appleby northward across what are now the Pennine Uplands 
maintained its course unchanged while the whole of it lay through 
rocks of uniform character. But as soon as the general lowering 
of the surface brought about the exposure of the older rocks—say, 
on Dufton Fell, then the course of the river must have been at 
once affected, for the softer rocks of Edenside wasted twice as 
fast as those of the newly-exposed Carboniferous rocks adjoining. 
(See fig. 3, pl. 1.) If I am correct in my inference that Maize 
Beck, for example, rose near where Cliburn is now, then the 
lowering of the surface there must, after a time, have proceeded at 
arate so much more rapid than it did to the North of Dufton Fell, 
that the head of the river must soon have fallen to a lower level 
than that of the hause, or co/, between Maize Beck and Haikable 
(“High Cup Gill.” The stream must consequently have been 
severed in two along the line where the softer strata had joined 
the harder. Maize Beck flowed on from then till now without 
important deviation; while the water collecting in its severed 
upper portion started anew, as it were, and, following the law of 
gravity, turned westward down the newly-formed declivity, and 
flowed into Edenside. 
I have little doubt that at one time all the rivers mentioned 
above, and—most especially—the Westmorland Lune, took their 
rise near Appleby, and that they have since had their several 
courses abbreviated by the diversion of part of the drainage in 
other directions consequent upon the differential lowering of the 
surface where they formerly originated. 
The same thing happened with some of the rivers of the Lake 
District. The Greta (at Keswick) once rose, if I am not mistaken, 
near Penrith, and it is only because the rocks that were formerly 
on the Penrith side have wasted more rapidly, that its head-waters 
have been tapped and diverted into other channels, Still, the old 
