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CHAPTER XXI. 



THE ORIGIN OF ESCARPMENTS, AND THE DENUDATION OF 



THE WEALD GREY WETHERS AND THE DENUDATION OF 



THE EOCENE STRATA. 



IN the foregoing pages much has been said about 

 escarpments. The origin of all escarpments, excepting 

 modern sea cliffs, is generally the same, and they are 

 nearly all marked by this peculiarity, that the strata 

 dip at low angles in a direction opposite to the slope of 

 the scarp, thus : 



FIG. 70. 



1. Strata with a low dip, e escarpment. 2. Detritus slipped from 

 the escarpment down towards the plain p. 



The Weald of Kent and Sussex and the surrounding 

 Chalk hills form excellent examples of what I wish to 

 explain, and I therefore return to the south-east of 

 England. In the Wealden area we generally find a 

 plain, bounded by hills of Lower Greensand and Chalk, 

 on the north, south, and west, while the clayey plain 

 itself surrounds a nucleus of undulating sandy hills in 

 the centre. The whole of this Wealden area forms a 

 great amphitheatre, on the outermost rim of which the 



