366 PROCEEDINGS COTTESWOLD CLUB 1912 



atmospheric denudation, and the comparatively short time 

 occupied by the Glacial Epoch, it may safely be inferred that 

 the greater part of the work of excavation had been accom- 

 plished before the advent of glacial conditions. The changes 

 by which the Severn river system was developed during the 

 Tertiary Period include the formation of the Warwickshire 

 Avon which cut across the course of a river that once drained 

 a part of the Trent Basin and flowed towards the south 

 through the Stour — Evenlode Valley. Another change was 

 the diversion of the Teme from its southerly course west of 

 the Malverns to a junction with the Severn below Worcester. 

 During the Glacial Epoch the drainage of the upper Dee area 

 was probably added to that of the Severn,' and the course of 

 the Avon appears to have been temporarily diverted to the 

 south of Bredon Hill. A gap in the ridge of Keuper and 

 Liassic rocks that extends for a long distance near the centre 

 of the Valley indicates a possible junction of the Teme and 

 Severn to the north of Wainlode Cliff.^ That the ridge was 

 then considerably eroded is probable, since it was exposed to 

 the full force of torrents that flowed from melting snow-fields 

 and the great ice-sheets. The wreckage may be seen in the 

 irregular masses of Keuper rock in the gravels at Upton-on- 

 Severn. 



Within the area under consideration the Severn receives 

 two important tributaries, the Teme and the Avon, which 

 must both have contributed largely to the superficial deposits 

 during the Glacial Epoch. The Severn now winds through a 

 valley filled with alluvial deposits, except in a few places where 

 it flows over Keuper rocks. 



Indications of elevation and depression in the Severn 

 Estuary and the Bristol Channel in comparatively recent 

 geological times have been described by various authors/ but 

 there appears to have been no appreciable change of level 

 since the Roman occupation. 



1 Prof. C. Lapworth, Proc. Geol. Assocn., vol. xv., 1898, p. 425. 



2 Cf. S. S. Buckman, Proc. Cott. N.F.C., vol. xii., p. 218. 



3 Cf. Strahan, Q.J.G.S., vol. lii., pp. 474-89- 

 Codrington, Ibui., vol. liv., pp. 273-6. 



A. Geikie, Ibid., vol. Ix., pp. xcvi.-cii. 



Prevost and Mellard Reade, Proc. Cott. N.F.C., vol. xiv., pp. 15-23. 



