THE SOTJTHERX PORTION OF THE WEALDEN AREA. 



653 



flints until after receiving the Pother and the Stor, two tributaries 

 which rise near the Chalk escarpment. The Adur, in both its 

 western and eastern branches, has flint-gravels only where its 

 tributaries rise in the flint-covered surfaces near its watersheds. 



Any tumultuous easterly current would certainly have mixed up 

 the detritus to a sufficient extent to have obliterated any such 

 evidences of a purely local origin. The theory, therefore, of a 

 torrential current, while certainly not required for the explanation 

 of the lower gravels, is inadequate to account for the origin of even 

 the watershed-drifts. 



Let us now endeavour to compare the drift-phenomena of Sussex 

 with those of neighbouring districts. When we turn to the 

 northern watershed of the Wealden area, we find there, as Mr. 

 Topley has long ago pointed out, extensive deposits of gravel, nearly 

 all of which can be referred to the action of existing rivers when 

 the} 7 flowed at a higher level. But in two separate localities gravel 

 deposits occur, the origin of which is not so clearly established. One 

 of these is at Limpsfield, at the western end of the Darent valley 3 

 where a coarse angular gravel occurs on the ivatershed, 500 feet above 

 sea-level. The other is at Warren House, near the eastern water- 

 shed of the Stour, where gravel containing Tertiary pebbles caps a 

 hill 300 feet above the sea. Of these two patches of gravel Mr. 

 Topley remarks that, under any theory, they are difficult to account 

 for, and their origin must for the present be left undecided *. We 

 see therefore that there is a general agreement in the drift-deposits 

 of the northern and southern portions of the Weald. In both cases 

 we find river-gravels, and also gravels on the watersheds, of which 

 the origin cannot be traced to any existing streams. 



If, now, we extend our observations beyond the Wealden area, we 

 find, in Hampshire and the Isle of Wight, gravel- deposits which 

 Mr. Codringtou considers to be of far greater age than the valley- 

 gravels of the rivers t. These gravels reach an elevation of 420 feet 

 in the Xew Forest and 390 feet on Headon Hill. jNow no one can 

 avoid being struck by the close resemblance between the Headon- 

 Hill gravels and those of the Wealden area of West Sussex. Mr. 

 Topley has already suggested a possible connexion between the 

 angular gravels of Midhurst and Pogate Commons and the higher 

 portion of the great Hampshire sheet of gravel in its easterly ex- 

 tension. Mr. Prestwich, again, in describing the Quaternary 

 phenomena in the Isle of Portland and around Weymouth, says : — 

 " Capping the high chalk ranges of Upton, the White Nore, and 

 Abbotsbury, is a thick bed of perfectly angular sharp chalk-flints in 

 a reddish clay reposing on a deeply-indented surface of chalk, while a 

 similar angular drift composed of fragments and masses of chert and 



ragstone caps the Upper-Greens and hills north of Abbotsbury 



I merely refer to them as haying been the storehouses whence much 

 of the latter drift-beds have been supplied " ±. Devon and Cornwall 



* Topley, ' Geology of the Weald,' p. 297. 

 t Quart. Journ. Geol. Soe. vol. xxxyi. p. 549. 

 \ Ibid. vol. xxxi. p. 41. 



