88 
and more of the Carboniferous ; until in the end, the Carboniferous 
rocks on the Appleby side of the old anticlinal were completely 
severed from their related rocks on the side around Kendal. The 
channel of the Lune for some distance above and below Borrow- 
bridge had already cut right through the Carboniferous rocks into 
the Silurian grits. 
A little consideration of these points, by the aid of the diagrams 
on Pl, 1, will readily enable one to understand the sequel. The 
tributaries of the Lune that began by flowing into the main stream 
by a direct westerly course from a position corresponding to the 
present summit of the Howgill Fells found their way into a channel 
whose bank on the south consisted of exceedingly tough grits, 
while its bank on the north was everywhere formed of the easily- 
eroded Upper Old Red and Lower Limestone Shales. The north 
bank consequently gave way readily everywhere, and receded down 
the slope as fast as the dissolution of the overlying calcareous beds 
laid it bare. Consequently these tributaries receded further and 
further northward as denudation proceeded, until their present 
position was reached. They are indeed in process of further 
recession even at the present moment. The drainage of the slope 
left by the northward recession of the Carboniferous rocks by 
degrees collected into new channels, which are now Uldale, Lang- 
dale, Ellergill, Weasdale, and Bowderdale. 
In the meantime the main stream north of Teba had also under- 
gone some modifications. ‘This, which I believe had its source 
originally somewhere above (ie. at a higher level than) where 
Gaythorn Hall is now, became detached as the Carboniferous rocks 
north of Orton were exposed by the northward recession of the 
New Red. Apart from the lowering of its higher gathering ground 
from the more rapid waste of the New Red, it is impossible for 
any river to collect water and to flow over an area of Mountain 
Limestone like that. The water sinks through the joints of the 
rock as fast as the rain falls; while, in addition, the northerly 
dip of the strata conducts the drainage well away to the north 
before the plane of underground saturation comes anywhere near 
the surface. So, with the comparatively-rapid lowering of the New 
