236 PROCEEDINGS OF THE COTTESWOLD CLUR 



If the main drainage of England and Wales was 

 originally Thamesvvard, and if the westward working back 

 of the l^rent, and the northward working back of the 

 Severn has successively tapped the upper Thames tribu- 

 taries, diverting them to the building up of their own 

 respective river-systems, it is obvious that, in their con- 

 tests with the Thames, the Trent and the Severn have 

 both had the immense advantage of working at lower 

 levels ; they have, as it were, been able to undermine the 

 Thames tributaries, and to give them a shorter and more 

 expeditious outlet seawards. But, when they came into 

 contest with each other, neither would have so marked an 

 advantage ; though that river, which had any such advan- 

 tage, should ultimately gain on the other, until complete 

 equilibrium was established. 



In its contest with the Thames the Severn still has an 

 immense advantage, as we may see anywhere along the 

 line of our Cotteswolds ; and it will retain this advantage 

 until it has eaten its way far into the Cotteswold country, 

 and until the degradation of that country has been carried 

 immensely further than at present. 



Another feature of this day's ride was the persistent 

 evidence of northern drift apparently throughout the 

 whole journey. There is a very fine section of this drift 

 in the Avon valley at Bengeworth, near Evesham. I did 

 not stop for its examination that day, as I had seen it on 

 other occasions. The collection of materials is remark- 

 able. There are pebbles and boulders of granite and 

 similar rocks,* of quartz and quartzites, of Jurassic lime- 

 stones ; and there are broken up flints. All are mixed 



* Some of the pebbles:. indicate much histor}'. For instance, oiu' is made up of 

 angular fragments which must have been derived from the waste of an older rock. These 

 fragments were cemented together to form a newer bed. That completed, the sea broke 

 that newer bed into fragments, rounded this pebble, and laid it down as part of a 

 newer conglonici ate. Out of that it was taken by some agency and carried along to be a 

 constituent of the drift in the Avon valley. 



