92 



SECTIONAL ADDRESSES 



when the ice still covered the watershed at Iron Bridge and at the head of 

 the Worfe, but had melted back enough to expose the upper Penk valley, 

 a small lake was impounded just north of Wolverhampton which flowed 

 out south-westwards over the watershed near Tettenhall, forming the 

 Tettenhall Gap. This overflow was responsible for the great train of 

 gravels full of Irish Sea erratics that follows the Smestow Brook down into 

 the Stour. 



Dixon has traced various ice fronts trending in a general north-easterly 

 direction across the country between the Penk and Newport, Salop. 

 These are marked by terminal kames and by beaded asar. 



► C/ac/ai J»-a.('n.aje Lines 



DdAfit— Irtfyi Ib/xo/r i\M/rs "exji and WULS. 



I c e-SCa nds 



Fig. 6. — The retreat phenomena of the Main Irish Sea Glacier. 



The Worfe valley was an important line of drainage from the ice front 

 until the latter came to lie on the north side of the watershed. In this 

 position a lake was impounded near Newport, and Dixon has shown that 

 this drained across the watershed at Gnosall into the Church Eaton brook 

 and so into the Trent. He named it Lake Newport. 



I have elsewhere described the detailed evidence relating to the way in 

 which the waters of the Upper Severn came to be diverted through the 

 Iron Bridge gorge into the drainage basin of the present Middle and 

 Lower Severn. This diversion was brought about during the melting 

 back of the Main Irish Sea glacier on the watershed region near the 

 Wrekin, through the development of a system of marginal channels and 

 glacial lakes. The detailed evidence substantiates a hypothesis suggested 



