514 The Thames. 



present Chalk escarpment, in its beginning, is thus of 

 older date than the Oolitic escarpment (fig. 57, p. 304), 

 but it would be hard to prove this, except on the hypo- 

 thesis I have stated. 



When this slope of the Chalk and the overlying 

 Eocene strata was established, the water that fell on 

 the long inclined plain east of the escarpment of the 

 Chalk necessarily flowed eastward, and the Thames, in 

 its beginning, flowed from end to end entirely over 

 Chalk and Eocene strata. 



The river was larger then than now, for I am inclined 

 to believe, that in these early times of its history, the 

 south of England was joined to France, the Straits of 

 Dover had no existence, and the eastern part of the 

 Thames as a river, not as a mere estuary, ran far across 

 land now destroyed, perhaps directly to join an exten- 

 sion of the north flowing river which we now call 

 the Ehine. At its upper end, west of its present sources, 

 the Thames was longer by about as much probably as 

 the distance between the well-known escarpment of the 

 Cotswold Hills and the course of the Severn as it now 

 runs, for the original escarpment of the Chalk must 

 have directly overlooked the early valley of the Severn, 

 which was then much narrower than now (see p. 509). 

 But by processes of waste identical with those that 

 formed the escarpment of the Wealden (figs. 71, 72, 73, 

 pp. 337-343), the Chalk escarpment gradually receded 

 eastward, and as it did this the valley of the Severn 

 widened, and the area of the drainage of the Thames 

 was contracted. 



By-and-by the outcropping edges of the Oolitic strata 

 becoming exposed, a second and later escarpment began 

 to be formed, while the valley of the Severn gradually 

 deepened ; but the escarpment of the Chalk being more 



