CXvi PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [May I906, 



way on to the shatter-belt at Grange at a fairly-late period in the 

 history of the rivers. 



It is probable that, at a very early period in the history of the 

 drainage, two important streams ran in the general direction of 

 the present Seathwaite and Stonethwaite feeders, uniting lower 

 down (perhaps near the present site of Derwentwater) to form the 

 Derwent, the drainage at this time being, of course, at a much 

 higher level than that of the present streams. 



The ancient Stonethwaite stream may indeed have flowed 

 past the site of Dub Tarn into the Watendlath Valley and past 

 Lowdore, for the Stonethwaite Valley is on the same line with 

 that of Watendlath, and there is a depression through Dub Tarn 

 connecting the two valleys. As this depression is over 1300 feet 

 above sea-level, the abandonment of this part of its course by our 

 hypothetical stream must (if it occurred) have been an early event. 

 The Seathwaite stream at this time, as we shall presently argue, did 

 not flow through the Jaws of Borrowdale, which were accordingly 

 then closed, so far as the main drainage was concerned, but were 

 no doubt occupied by some stream the actual course of which was 

 sufficiently close to the shatter-belt to allow of the stream working 

 into it. This stream may well have been that which rises on 

 Glaramara and flows through Combe Gill. 



Granting the possibility of this arrangement, the present features 

 connected with the drainage are readily explicable. 



The stream from Combe Gill would enter the shatter-belt which 

 extends up the Seathwaite valley east of Seatoller ; flowing north- 

 eastward it would join the shatter- belt which now passes Eosthwaite 

 and the Jaws of Borrowdale close to the site of Seathwaite Church, 

 and would flow along this belt through the ' Jaws ? on to the 

 Skiddaw Slates. This stream, working back from the fall-line, would 

 cut a gorge through the ' Jaws,' and up the present main valley to 

 Seathwaite Church, and then along the more southerly shatter-belt 

 to the foot of the present Combe Gill. 



"We will now consider the changes which would occur along the 

 lines of the two great feeders of Stonethwaite and Seathwaite, 

 beginning with the former, the structure of which is comparatively 

 simple. 



A tributary stream would enter the stream that has been just 

 described, from above Seathwaite ; its valley running along a 

 shatter-belt would be deepened, and receding would capture the 



