Vol. 62.] ANNIVERSARY ADDRESS OE THE PRESIDENT. CXV 



originally existed as the result of the elevation of the dome. (See 

 fig. 7, p. cxiv.) 



At the present day the Borrowdale valley is occupied by a 

 stream formed by the coalescence of two feeders, the Seathwaite 

 Beck 1 from the south-west and the Stonethwaite Beck from the 

 south-east, which unite below Rosthwaite, and the River Derwent 

 formed by their union flows northward to Derwentwater. The 

 true head of the Derwent is on the Scawfell group of fells, and the 

 valley is one of the original radial valleys due to the elevation of 

 the dome. The Derwent passes from the volcanic rocks on to the 

 Skiddaw Slates, near the village of Grange. Its erosive power over 

 the tract occupied by the volcanic rocks was no doubt due, as 

 in the case of so many other valleys, to the more rapid denudation 

 of the Skiddaw Slates in earlier times, producing a fall-line at 

 the junction of the two sets of rocks. Above this junction at the 

 present day the courses of the Derwent and its two principal feeders 

 coincide with the trend of three important shatter-belts. The 

 lowest of these runs in a general southerly direction from Grange 

 through the Jaws of Borrowdale, past Rosthwaite and Stonethwaite 

 Beck, above Stonethwaite in the direction of the Greenup valley. 

 Its existence is indicated by the geological structure, for on its east 

 side for a long distance is the Falcon-Crag Group of volcanic rocks, 

 and on its west side the Ullswater Group. At Galleny Force, 

 about 1 mile south-east of Stonethwaite, another shatter-belt, the 

 existence of which has already been considered, passes up the 

 Langstrath Beck to its head. 



At Stonethwaite Church another belt passes up the Seathwaite 

 feeder as far as Seathwaite hamlet, its presence being also indicated 

 by the geological structure, among other things by the disappearance 

 of the igneous rocks around the graphite-mine on the west side of 

 Seathwaite Valley. South of this the belt turns due south (where 

 another belt runs obliquely across the valley) and is traceable up to 

 and beyond the head of Grainsgill. 



It is in the highest degree improbable that the stream initially 

 produced as the result of the establishment of the radial drainage 

 should have coincided with a shatter-belt, at the point where it 

 crossed from the volcanic rocks to the Skiddaw Slates ; and all the 

 modifications which I am about to describe can be accounted for, on 

 the supposition that the waters of this drainage-system found their 



1 This is, of course, a different Seathwaite from that of the Duddon Valley. 



