230 MR. PHILIP LAKE ON BALA LAKE AND [May I9OO, 



12. Bala Lake and fJie River-System of North Wales. 

 By Philip Lake, Esq., M.A., F.G.S. (Head February 7th, 1900.) 



[Abstract.] 



In this paper the Author begins by showing that topographically 

 Bala Lake belongs to the same valley as the River Wnion — the 

 valley of the Bala Fault ; and he believes that the whole drainage 

 of the valley originally flowed south-westward, and entered the sea 

 near Barmouth. 



He then examines the possible outlets, and shows that the lake 

 is probably rock-bound in all directions except towards the south- 

 west, where there is no conclusive evidence. 



He describes the faults which occur near the watershed that 

 separates the Wnion from the streams flowing into Bala Lake, 

 pointing out that they are closely related to the form of the valley, 

 and that the watershed coincides with a transverse line of fault. 

 From this he infers that the formation of the lake is possibly due 

 to earth-movements. 



The watersheds of several other similar valleys are examined, 

 nnd are shown to lie in one straight line ; whence it is concluded 

 that they must have been produced by some general cause, probably 

 a slight differential movement. 



The general drainage-system of North Wales is next discussed. 

 Attention is drawn to the existence of a series of long and nearly 

 parallel valleys running from north-east to south-west, which divide 

 the region more or less completely into a number of strips. The 

 drainage of each strip is now independent, and flows in most cases 

 into the long valley lying south of it. But from the fact that the 

 chief streams in each strip have their representatives (flowing in the 

 same line) in the adjacent strips, it is concluded that before the 

 formation of the long valleys the streams were continuous. 



The centre from which these streams radiate lies in the high 

 ground near the sources of the Conway; and the Author believes 

 that this was the centre of an original radial system of drainage, 

 and that this radial system was subsequently broken up into 

 sections, by the formation of the long valleys which now run from 

 north-east to south-west — each of these long valleys carrying away 

 the drainage of one of the sections. He attributes the formation 

 of the long valleys to faulting. 



Discussion. 



Mr. Hopkinson said that he came to hear this paper expecting 

 that it would have a direct bearing on the question of obtaining a 

 supplementary supply of water for London from Bala Lake. 

 Although he was disappointed in that, he had listened to the 

 Author's admirable exposition with the greatest interest, perhaps 



