﻿Vol. 66.~] THE WESTERN END OF THE WEALD. 661 



(B) River Blackwater. 



The present and past connections of the Blackwater with the 

 "Wealden area were discussed in a former paper (2), but some 

 repetition here will tend to greater clearness. The pass between 

 Hungry Hill and the Hog's Back (called in fig. 1, p. 642, the Alder- 

 shot gap) is divided into two valleys by a ridge ending in a mound 

 of Chalk at Badshot Farm. The western valley was occupied until 

 quite recently by the Farnham River ; while the eastern is still 

 traversed, when any water is there at all, by the Seale stream. 

 1 formerly assumed that these two valleys had, at an earlier stage, 

 been united ; but, since I wrote, Mr. G. W. Young (29, p. 432) has- 

 shown that there are two dip-faults, where only one is mapped by 

 the Geological Survey, and that these two faults correspond in a 

 striking degree with the two valleys. It is, therefore, quite possible 

 that the latter have always been distinct, and that the faults actually 

 determined from the first the courses of the two streams, a view 

 which has been embodied in fig. 5 (p. 666) ; but I should like to have 

 more definite evidence as to the courses of the faults before finally 

 endorsing it. As is well known, the strike undergoes a change at 

 this point, the Hog's Back running almost due east and west, while 

 the hills on the north of the Farnham Valley run nearly east-north- 

 east and west-south-west. The original head of the Blackwater, the 

 course of which is now indicated by the Waverley Valley, ran at 

 right angles to this western strike, and the two principal subsequent 

 rivers enter from this side. One of these is the Farnham River, 

 which, as far west as Bentley, formerly ran along an anticline, its 

 gravels being still visible on the Alice Holt Plateau. The second, 

 the Tilford River, appears to run in a syncline ; it is not easy to 

 trace the exact position of such a fold in the soft Folkestone Beds, 

 but there is certainly a southerly dip in Alice Holt and Farnham 

 Common immediately to the north, and a rise again farther south 

 near Churt. There is strong evidence that this Tilford River was 

 developed very late, as a westward continuation of the Godalming- 

 branch of the Wey ; therefore it never really formed part of the 

 Blackwater at all : for, in Pleistocene (late Palseolithic) times, 

 transverse streams still carried chert from Hindhead directly into 

 the Farnham River. 



There is a third longitudinal stream, which, though of small 

 dimensions, presents some points of interest — namely, the stream 

 that rises near Haslemere, and flows in a deep valley between 

 Blackdown and Hindhead to join the Headley River. In the first- 

 place it flows westwards, while the two subsequent rivers just 

 mentioned flow eastwards. The latter course is the more intelli- 

 gible, because, in consequence of the westerly dip, the exposure 

 of the soft beds, to which the subsequent streams owe their 

 origin, would usually begin in the east, and spread westwards : 

 there would, however, be no difficulty in understanding the course 

 of the Haslemere stream, if it could be regarded as of somewhat 

 late origin, but that does not appear to be possible. The water- 



