﻿MURCHISON — FLINT DRIFT OF S.E. ENGLAND. 373 



Lying in a gently sloping common from which the chalk-hills rise up 

 to the north, these pebble-beds are completely shut out from the sea- 

 coast by the advanced chalk-hill called the " Miller's Tomb," which, 

 acting as a buttress, has, I conceive, checked the outscouring or de- 

 nudation which has swept away and re-aggregated the greater portion 

 of the tertiaries along this tract, and has so powerfully eroded the 

 surface of the chalk and shattered its flints. The raised sea-beach at 

 Brighton, which is proved to be very modern by the remains of existing 

 sea-shells and cetacean bones, as well as by some portions of ter- 

 restrial quadrupeds, which were found in it, together with foreign 

 pebbles, differs very greatly in composition and contents from this old 

 tertiary deposit ; although the well-rounded flints of each are scarcely 

 to be distinguished, and both, resting on eroded chalk, are covered 

 by the angular drift. The tertiary clay of Patching, which is an ex- 

 tension of the deposit of Clapham Common, supports the large pond 

 of Patching ; no other such extensive piece of water being met with 

 upon the surface of the chalk. 



Detritus of the Hampshire Chalk Range and of the North Downs, 

 as distributed towards the Weald and over the Tertiary Deposits. — 

 The chalk-escarpments which unite the South Downs with the North 

 Downs are for the most part clean denuded along their base (Frox- 

 field and Selborne Hangers) . Like the South Downs, however, from 

 which they branch off, they are subtended by coatings and irregular 

 patches of flints which cover the eroded surface of the hills of Lower 

 Greensand which lie nearest to them. Thus, whilst the terraces of 

 Upper Greensand and valleys of Gault are for the most part denuded, 

 the sandy tracts near Liss and Greatham and the white sands of 

 Woolmer Forest, like those of West Heath and Trotton Common, 

 have arrested considerable heaps of them. Here again the debris 

 is purely chalk-flint, probably derived from the same great angle of 

 the fractured and denuded chalk west of Petersfield before alluded 

 to. The debris may here have been translated from South to North, 

 in the depression between the Selborne Hangers and the highest 

 parts of Woolmer Forest. No fragment of these flints has been 

 translated to the sides of the higher grounds further removed from 

 the Hampshire or north and south escarpment of chalk. When the 

 great Wealden denudation is viewed near its western end, as the ob- 

 server moves along the high-road from Portsmouth to London, the 

 grounds occupied by the Lower Greensand, already described at Rake 

 Common (see above, p. 357), are seen to rise considerably. That 

 formation, as indicated by Dr. Fitton and myself, attains in fact a 

 greater elevation in Hind Head (872 feet) than in any part of its 

 range, except in the eastern prolongation of the same ridge to Leith 

 Hill, which is 960 feet above the sea. Whether the summits of 

 these hills, or the deep combes within them, be examined (and of 

 these the Devil's Punch-Bowl is the most notable example), they are 

 found to be free from all loose transported materials, and denuded 

 down to the surface of the rock, which is only partially covered by 

 a very scanty soil and a meagre vegetation of heath. No sooner, 

 however, do we move north-westwards towards the escarpment of 



