XCvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May IO,o6 r 



the line of uplift of the dome, as indicated by the geological 

 structure of the margin of the district. 



On the north side of this watershed, tracing the valleys from west 

 to east, we have the Thirlmere valley, which, though now largely 

 along a shatter-belt, probably runs in the general direction of a valley 

 due to a superimposed stream ; the Ullswater valley ; and those of 

 Haweswater and Swindale. While, south of the shedding-line, 

 again proceeding from west to east, we note first a valley which 

 started near the head of Troutbeck and, as will be maintained later, 

 joined Kentmere at Staveley; Long Sieddale; and Borrowdale (not 

 the well-known valley of that name, but one the stream of which 

 joins the Lune at Low Borrow Bridge). 



Taking next the supposed subsidiary uplift of the Skiddaw tract, 

 we again meet with a radial drainage on a smaller scale. Such 

 drainage must, of course, be developed on any mountain of circum- 

 denudation, but in this case the evidence seems to me in favour of 

 subsidiary uplift. The principal streams start from Skiddaw Forest. 

 To the north-west runs Dash Beck, to the south the Glenderaterra 

 (now largely coincident with a shatter-belt), to the east the upper 

 waters of the Caldew, and to the north a tributary of that river. 



More complex is the drainage of the tract of land comprising the 

 Howgill and Kirkby-Lonsdale Fells and those fells on the east which 

 are now composed of Carboniferous rocks. 



A series of valleys radiate from a point above Widdale Fell, near 

 Hawes. To the north run the headwaters of the Eden, to the west 

 those of Garsdale and Dentdale, to the south the upper waters of 

 the Kibble, to the south-east Langstrathdale, and to the east 

 Wensleydale. 



The fact that Silurian rocks are exposed at the surface (save in 

 the inliers along the Craven Fault) to form the fells of the western 

 portion only of this tract is naturally accounted for, on the sup- 

 position that the Dent Fault, which threw the Carboniferous rocks 

 down to the east, was of New-Red-Sandstone age ; and that, after 

 the faulting, denudation took place and the levelled tract was 

 subsequently covered by newer (Jurassic and Cretaceous ?) rocks, 

 on which the drainage was initiated. 



But there is one feature that requires notice. The Lune, from 

 Tebay to Kirkby Lonsdale, runs in a gorge through the centre of 

 that part of the uplifted tract which is occupied by Lower Palaeozoic 

 rocks. Geographically, this river rises at Shap Summit. It is true 



