Cxii PEOCEEDIXGS OF THE GEOLOGICAL SOCTETT. [May I906,, 



valley of Tarn Beck. In connexion with the old drainage, we may 

 notice a curious dry valley between Hinning House and Troutal, 

 at a considerable height above the present stream. Seathwaite 

 Tarn lies in one of the most important of the hanging valleys 

 of Lakeland, which, beginning at the top of the Carrs (one of the 

 Coniston Fells), runs in a sinuous course for a distance of 2 miles, 

 measured in a straight line, before it mouths at a height of 1075 

 feet above sea-level and 375 feet above the wide Tarn-Beck valley 

 at the bottom of the slope. This valley is occupied by alluvium at 

 its base, until it reaches the Wallabarrow ridge to be noticed anon. 

 Below the entrance into this valley of the stream forming Sea- 

 thwaite Tarn there is evidence of another meander marked by a 

 ridge of apparently-waterworn rock at Long House, at a height of 

 100 feet above the present river on the west, and a wide dry valley 

 extending from this ridge to Seathwaite Church. The height of 

 the Long-House ridge is 550 feet above sea-level. 



We now come to one of the most interesting features of the 

 valley. The rocky ridge of Long House is the eastern part of a 

 great rocky spur which rises, on the whole, westward. Below it 

 the Duddon is a wide valley largely occupied by alluvium, although 

 there are evidences of other ancient meanders now cut through 

 along shatter-belts. Looking at this ridge, part of which is known 

 as Wallabarrow, from down vale, it appears completely to block 

 the valley ; but two deep gorges cut through it, one occupied by 

 the present Duddon, the other by Tarn Beck. 



Above Wallabarrow Gorge, a stream enters the Duddon from the 

 west, flowing past a farm called Grasgors, below which it mouths 

 at 950 feet, and on the other side of the Duddon is a deep notch in 

 the ridge separating the Duddon from the Tarn-Beck valley, the 

 height of this notch being 525 feet above the sea. 



Anyone looking up the valley from below, or looking down upon 

 it from Walney Scar on the Coniston Pells, would be convinced 

 that the main river ran over the Long-House ridge, which is 

 now dry. 



The changes which seem to have occurred are as follows : — In 

 former times when the Duddon below Birks Bridge ran into the 

 Tarn-Beck valley and over the Long-House col, the Grasgors 

 stream would run through the notch east of the present Duddon, 

 to unite with the old river above Long House, while a tributary 

 of Grasgors would no doubt flow from the north. The first 

 change was the formation of a gorge through the Wallabarrow 



