5S 



been overborne and masked by what Mr. Topley has 

 denominated "The Chief Anticlinal lines of the Weald," 

 in his memoir. 



The upheaval of the Wealden Dome, besides causing 

 a series of flexures or rugae peculiar to the form of the 

 upheaval, may be supposed to have started many an 

 older fracture, and for short distances that fi-acture would 

 serve for the new direction which a flexure required to 

 take, thus we should find the flexures to be formed of, so 

 to say, horizontal steps. This arrangement may be found 

 on the chalk hills, or on either side of the Weald, giving 

 rise to valleys running across the dip and nearly at right 

 angles to the main stream lines, which run with the dip. 



It will be noticed too, that these valleys often have on 

 the side aAvay from the Weald a series of small patches of 

 tertiary beds, marking the edge of a ruga or flexure. To 

 the existence of this tertiary escarpment as it may have 

 been, is credited the peculiar direction of the valley, rather 

 than, as I take it, to the line of weakness having diverted 

 the stf eam for the benefit and preservation of the tertiary 

 patches. 



The rivers of the Weald run most extensively along 

 the softer beds in the lateral or longitudinal valleys, uniting 

 to pierce the harder ridges in transverse valleys. 



The chalk escarpment is pierced by the Medway, 

 Darenth, Mole, and Wey, which rivers continue to run 

 through the chalk gaps as on the day they commenced 

 their courses. 



Mr. Topley* thinks that " originally there were six 

 rivers passing out of the Weald to the North," which he 

 enumerates as the Rother, Stour, Medway, Dart, Mole, and 

 Wey ; to these I would add the Lesser Stour by the Gap 

 at Lyminge, the Old Wandle with the Caterham stream 

 by their Gaps at Merstham and above Oxted, and the Old 

 Blackwater by the Gap at Aldershot, and others. In the 

 list below I have compared some of the more conspicuous 



* Loc. cit. 



