176 Geological Society. 



2. ' The Glaciation of Teesdale, Weardale, and the Tyne Valley, 

 and their Tributary Valleys.' By Arthur Richard Dwerrvhouse, 

 Esq., B.Sc., F.G.S. 



After an account of the topographical solid geology of Teesdale, 

 the author describes the four distinct types of Drift in the area as 

 follows : — 



(a) A sandy reddish -brown clay, with a large number of well-scratched stones : 



(b) A black loamy or peaty clay ; 



(c) A coarse gravelly deoosit. with many waterworn and a few scratched stones ; 



(d) A stiff blue Boulder-Clay. 



The first class is the most widely distributed ; it occurs in elon- 

 gated ridges, and is the direct product of ice-action on the rocks of 

 the upper part of the Dale. The black loamy clay is characteristic 

 of areas occupied by ice-dammed lakes. The third class occurs in 

 long esker-like ridges, and is particularly plentiful in the country 

 formerly occupied by the Stainmoor glacier. The dark-blue clay 

 is mainly derived from Carboniferous rocks. A detailed description 

 of the Glacial deposits, boulders, and striae is next given ; and from 

 this the following conclusions are deduced : — Upper Teesdale was 

 heavily glaciated by local ice from the eastern slope of the Cross 

 Fell Range ; this part of the Dale was not invaded by any other 

 ice, and the higher peaks stood out as nunataks. At the period 

 of maximum glaciation a number of lakes were formed, owing to 

 the obstruction of the drainage of lateral tributary-valleys by the ice 

 of the main glaciers. Lunedale was occupied by ice (the Stainmoor 

 glacier) which came from the drainage-basin of the Irish Sea, 

 joined the Teesdale glacier about Middlcton-in-Teesdale, and by its 

 thrust deflected the Teesdale ice into the Valley of the Wear. 

 During the retreat of the ice there was a lengthened period of 

 ' constant level/ when well-marked drainage-channels were formed, 

 and after this the ice was removed with great rapidity. A tongue 

 of ice flowed from Upper Teesdale by Yad Moss to the Valley of the 

 South Tyne. 



Similar evidence with regard to Weardale and the Tyne Valley is 

 given, and the following conclusions are drawn among others : — Ice 

 from Teesdale and the tributaries of the South Tyne occupied the 

 valley of the latter nearly as far as Lambley, where it was joined by 

 a large glacier which crossed the northern end of the Pennine 

 Chain. This glacier was continuous in a northerly direction with 

 the ice of the Southern Uplands and the glacier of the North Tyne, 

 and, when at its maximum, deflected the last north-eastward, 

 causing a movement in that direction along the southern flanks of 

 the Cheviot Range. But at the beginning and end of the glaciation 

 the ice in the Valley of the North Tyne flowed south-eastward. The 

 southern margin of the South Tyne glacier passed across the heads of 

 Allendale and Devil's Water into the Wear Valley ; and along this 

 margin were a series of ice-dammed lakes with a corresponding 

 series of overflow-channels, many of which are now streamless. 

 Weardale was mainly occupied by its own ice, but the lower part of 

 the valley was invaded by the Tyne ice from the north and that 

 of the Tees from the south. There were no lakes strictly connected 

 with the last system. 



