﻿672 MR. H. BURY ON THE DENUDATION OF [Nov. I9IO, 



by assuming that the Chalk was planed off, across its whole outcrop, 

 to a thin layer, all the objections derived from the immaturity of 

 the river-system, which were urged against the subaerial theory, 

 apply to this hypothesis as well. 



(C) River Wey. 



As in the case of the Blackwater, I shall first describe the 

 phenomena in terms of the hypothesis of marine planation, 

 afterwards pointing out the difficulties which lie in the way of 

 the theory of continuous subaerial denudation. 



If we exclude the area formerly drained by the Blackwater, the 

 Wealden portion of the Wey may be said to consist of a main 

 consequent trunk, and one subsequent tributary on each side. An 

 important longitudinal fold runs along the whole front of the area 

 thus drained, and reaches its greatest development at the very 

 point at which it is crossed by the consequent river, thereby giving 

 rise to the Peasemarsh inlier. No name was given to the consequent 

 stream on the Ordnance Survey maps, but it is called by Martin 

 (11, p. 72) the Shalford Brook, and as such it will be convenient 

 to refer to it in this paper. It rises in the Weald Clay, receiving 

 at its head a subsequent stream from the east ; but its territory has 

 been greatly encroached upon by the Arun, and it will be more 

 convenient to defer consideration of this portion of it until the 

 latter river has been described. 



The western subsequent river (Godalming River) runs in the 

 Lower Greensand, and for the most part in a shallow syncline, 

 about 4 miles from the Chalk. The main part of the eastern 

 subsequent (Tillingbourne) is much closer to the escarpment, and 

 appears to coincide, in part at least of its course, with the anticline 

 already mentioned, but there is a second longitudinal stream about 

 a mile farther south, which runs for some distance nearly parallel 

 with the Tillingbourne before joining it. 



There are but few well-marked notches in the crest of the Chalk 

 escarpment throughout this region, yet I think that, with a little 

 study, the former passage across it of several consequent streams 

 can be inferred with some confidence. Taking first, for the sake 

 of clearness and convenience, the country to the east of Guildford, 

 we find 6 miles from this town the well-known sands of Netley 

 Heath, for which Mr.Stebbing's researches (25, pp. 524-26) strongly 

 suggest a Pliocene date. It is, however, no part of my purpose to 

 discuss the age of these beds, but merely to call attention to the 

 gravel containing a good deal of chert which everywhere overlies 

 them. Mr. Stebbing simply records its existence in each of the four 

 sections detailed by him, without speculating on its origin ; but I 

 think that most observers, having regard to its relations and com- 

 position, and to the frequency with which it occupies channels 

 ploughed in the sands, will agree in assigning it to fluviatile action, 

 and therefore I may fairly claim it as the work of a consequent 



