﻿326 ME. H. BURT OJf THE EIVEE WEY. [May I908, 



considered the lowest point), drops with some suddenness to a lower 

 platform, half a mile or more in extent, before its final plunge into 

 the Waverley Valley. The relation of this platform, which is still 

 well over the 300-foot level, and is covered with gravel, can best be 

 studied at the end of the northern ridge, on which the following 

 gradients are found : — 



1. From Alice Holt (400 feet) to Greenhill (353 feet, about a mile south- 



east of Farnbam) from 1 in 650 to 1 in 250. Average for 3^ miles = 

 1 in 413. 



2. From Greenhill to the edge of the Waverley Valley (about 320 feet), 



1 in 90. 



3. Slope of Waverley Valley =1 in 12. 



It is, I think, a reasonable assumption that this lower platform 

 is a remnant of the left bank of the consequent valley as it was just 

 before it was beheaded. How much farther east it extended and how 

 much lower than 320 feet it fell, there is no direct evidence to show, 

 since the old bed of the river, together with the whole of its right 

 bank, has been destroyed in the formation of the obsequent Waverley 

 Valley. Taken, however, in connection with the Chalk mound 

 (295 feet) in the pass a mile farther north, it justifies, I think, my 

 assumption that the latter represents approximately the level of the 

 river at the time when it was beheaded. Further evidence may 

 perhaps be derived from the character of the gravel of this lower 

 platform on the northern ridge, but at present only a superficial 

 examination is possible, and that is seldom satisfactory : so far I 

 have found but few Hythe-Bed pebbles in it : but it is curious that 

 these pebbles, which are scarce along most of this ridge, suddenly 

 become common at Greenhill. In view of this irregularity in their 

 distribution, it would probably be unwise to draw conclusions from 

 the presence or absence of these Hythe-Bed fragments on the 

 various portions of the plateau ; but a few general remarks may be 

 useful. Many of them are 'distinctly angular, and although they 

 must have come originally from Hindhead,^ may have reached their 

 present position only from an older drift ; but the bulk of them 

 probably came direct at the time when the plateau was formed. 

 How many streams were concerned with this supply, it is impossible 

 now to say, but probably the principal source was the Headley Biver ; 

 and to this I attribute the formation of the south-western portion 

 of xilice Holt, which, as the map (PI. XXXVI) shows, is out of the 

 line of the river coming from the Alton Valley and forming the rest 

 of the plateau. This connection of the Headley with the Farnham 

 River appears to have been maintained, after the plateau was 

 abandoned, along the line of the Blacknest Stream, which cuts a gap 

 in the line of hills almost 100 feet deep, and only 50 feet above 

 the bed of the Farnham Eiver. Xo doubt this Headley stream 

 was finally captured by the Tilford Eiver (which must until then 

 have been but small), though I know of nothing to show exactly at 

 what stage this took place. 



1 R. A. 0. Godwin-Austen (Quart. Journ. Geol. Soc. vol. iv, 1848, p. 260) 

 attributes tbe ' cberty sandstone ' so common on tbe southern ridges to tbe 

 Upper Greensand ; but I bare failed to match it among local specimens of 

 tbat age, and believe tbat almost tbe whole of it comes from tbe Hjtbe Beds. 



