﻿324 ME. H. BTJEY OX THE EIVEE WET. [May I908, 



ridge, a general slope to the north-east ; but there are indications 

 also of a less regular slope towards the south-east, as the following 

 measurements, taken along lines at right angles to the Earnham 

 Yallej', will show : — 



Feet. 



1. North-westeru corner of Alice Holt 400 



1 mile south-east of this 393 



f mile farther south-east 3(il 



2. Clay Hill (Wrecclesbam) 388 



Base of southern ridge (Rowledge) 367 



3. !Xorthern ridge (a little east of 'Highlands') 370^ 



Eastern end of middle ridge 374 



Southern ridge (corresponding part) 349 



The actual heights would, of course, be altered by removing the 

 drift which is present at all these points, but the relative levels 

 would scarcely be affected. 



The northern edge of the plateau corresponds approximately with 

 the axis of the flexure which gives rise to the Peasemarsh inlier 

 (near Guildford), and is here dying away, not being traceable 

 farther west than Bentley - : and this flexure gives rise not only to a 

 westerly dip, which brings the Lower Greensand to the surface 

 about half way along the northern ridge, but also to a slight 

 southerly dip, in consequence of which this outcrop of the Lower 

 Greensand is pushed farther eastwards on the southern ridge than 

 on the northern, although, as we have seen, the former is somewhat 

 the lower. With the exception of these eastern ends of the ridges, 

 the whole plateau consists of Gault. 



Patches of drift (mostly gravel) occur on all the higher parts of 

 the plateau, especially along the northern ridge, where its greatest 

 depth is given by Lasham ^ as 40 feet, and by Monckton & Mangles ^ 

 as 25 feet : it would be interesting to know the exact spots at 

 which these very great depths occurred, bat I do not think that 

 they can have been on the crest of the ridge, where the thickness 

 rarely exceeds 10 feet. It is from this northern ridge that the 

 most perfect of the well-known Palaeolithic implements of Farnham 

 have been obtained ; many, it is true, occur in the gravel-beds 

 slightly lower down, on the southern slope of the Farnham Yalley, 

 but these are almost invariably waterworn/ and are probably 

 derived from the plateau. The drift of the middle and southern 

 ridges is usually much less thick, and varies greatly in character, 

 being sometimes mainly sand ; but where gravel occurs it is very 

 similar in character to that of the northern ridge, except that it 

 contains a far larger percentage of chert and other Lower Greensand 

 pebbles. Monckton & Mangles, whose careful account of the 

 Farnham gravels should be consulted, describe as a river-gravel a 

 bed (marked D on their diagram), which lies apparently at the base 



^ This is approximate onlj- : the rest are from the Ordnance Map. The last 

 of the series (349 feet) probably does not belong to the plateau proper: see 

 p. 326. 



2 ' Geology of the Weald ' Mem. Geol. Surv. 1875, p. 229. 



' Coll. Surrey Archaol. Soc. vol. xi, p. 27. 



* Proc. Geol 'Assoc, vol. xiii (1893-94) p. 77. ^ Ibid. p. 78. 



