﻿Vol. 66. ~] THE WESTEKX END OE THE WEALD. 683 



southern face of the Lower Greensand escarpment between Hind- 

 head and Hascombe : it thus extends far to the north of any 

 probable position of the central watershed, and invades territory 

 which we should naturally expect to find included in the basin of 

 the Wey. I think it can be shown, not only that such an invasion 

 has taken place, but that the transference of this region from the 

 Wey to the Arun is of comparatively recent date. The head-waters 

 of the Wey take a sharp bend at a point, about a mile to the north 

 of Laker's Green, which may be taken as the junction of a subse- 

 quent with a consequent stream ; and the ground all around this 

 point is extremely Hat, having evidently undergone a long and 

 complete adjustment to the river-level. On the south there is a 

 gradual rise to the high ground between Ali'old and lludgwick; and 

 while on the east the valley of the subsequent stream soon narrows, 

 on the west, although no stream joins the Wey from this side, 

 the gently sloping plain can be followed beside the Wey & Arun 

 Canal as far as Tickner's Heath, and thence past Dunsfold into the 

 neighbourhood of Chiddingfold. 8outh and west of Dunsfold the 

 plain, gradually rising, can easily be traced for some distance, 

 but it is intersected by numerous branches of the Arun, running in 

 steep-sided valleys about 70 to 80 feet below the plain-level. It 

 is impossible to represent all this on a map, but I think anyone 

 who carefully studies the district will agree with me that the obvious 

 adjustment of this plain to the head of the Wey, and the entire 

 lack of adjustment, in spite of the soft soil, to the Arun, are proof 

 that the latter has here effected a very recent capture — so recent, 

 in fact, that the level of the Wey has since undergone no appreciable 

 change. The accurate mapping of the plain would be a task of 

 considerable interest for anyone living in the neighbourhood; but 

 in a thickly wooded district this is no easy matter, and though I 

 have followed it up in many directions, I have still much to learn 

 concerning it. In the map (fig. 8, p. 684), therefore, in which I have 

 endeavoured to indicate the former watershed and its relation to 

 the rivers, I have not attempted any complete reconstruction of the 

 old drainage-system. 



We turn next to the easternmost of the two rivers forming the 

 head of the Arun, which may for convenience be referred to as 

 the Horsham Hiver ; and here the first question confronting us is 

 whether it is a subsequent or a longitudinal consequent river ; 

 against the latter theory may be urged (a) that no other such river 

 has been definitely proved to exist in this area, and (6) that there 

 is no evidence of a synclinal fold which such a river requires. A 

 longitudinal tributary of the Ouso practically continues the line of 

 the Horsham River eastwards, and so long an alignment of river- 

 valleys suggests a structural cause ; yet, although there is a syncline 

 near Slaugham, the Ouse does not run in it, but to the north of 

 it, and the fold itself seems to die away before the Arun is reached. 

 It must, of course, be admitted that, especially on an impervious 

 soil, an amount of folding which would be practically imperceptible 



Q. J. G. S. No. 264. 3 a 



