CHAPTER XVII 

 HISTORY OF LANDSCAPE 



IT is sometimes found that there are unexpected irregularities 

 in the run of landscape features, which appear at first to contradict 

 the law of adjustment. Thus in the Weald there are sometimes 

 hills rising along the line of the Weald Clay or other soft beds ; 

 on the other hand, the Ragstone Range attains very great im- 

 portance at certain spots, and dwindles down to nothing else- 

 where (Fig. 64). These exceptional occurrences are found on 

 closer examination to emphasise rather than contradict the law 

 of adjustment, for they are due to local and exceptional causes. 



The dying out of the Ragstone Range as it approaches East- 

 bourne from the west is due to the thinning and wedging out of the 

 hard beds, and their replacement by clays which do not differ in 

 resistance from the Weald Clay below and the Gault above. 

 The marked development of the same range at Leith Hill and 

 Hindhead is due partly to the thickening of the hard rocks, 

 partly to the more complete cementing and hardening of the 

 individual beds, and in part to the nearly horizontal position 

 of the rocks, which form a long, flat dip-slope, where the Gault 

 has been denuded from above them, and a very abrupt scarp, 

 where the Weald Clay has been undercut beneath them. 



The occurrence of occasional hill ranges along the Wealden 

 Valley is due to the existence of beds of fresh-water limestone in 

 the neighbourhood of Horsham and Petworth, which are much 

 more resistant than the Weald Clay with which they are inter- 

 bedded. Similar occurrences are to be noted in the thickening, 

 thinning, or dying out of shales and grits amongst the escarp- 

 ments on the east and west sides of the Pennine Chain. 



Other irregularities are found to be caused by smaller and 

 subsidiary wrinkles on the larger rock folds. Each becomes 

 denuded in its special way according to the rocks of which it is 



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