276 DILUVIUM. 



the chalk in which the flints were imbedded has been entirely destroyed, 

 the latter have sustained but very Uttle injury. 



Descending into the vallies, accumulations of chalk rubble and ochra- 

 ceous clay, are again seen lying upon the basseting edges of the solid 

 strata; and the slopes of the hUls are generally composed of similar 

 materials. Examples of this kind occur in almost every locality of the 

 South Downs. 



The gravel-pits (as they are called) of Barcombe, are part of a ridge of 

 broken chalk flints, shghtly rolled, resting upon a bed of ochraceous clay. 

 The flints are of various shades of yeUow, brown, and carnelian. The 

 colour, which in aU probability results partly from decomposition, and 

 partly from an impregnation of metallic oxides, pervades the substance of 

 the flint, but is much paler towards the centre than on the surface. These 

 flints are not reduced to the state of pebbles, much less of gravel, but are 

 merely broken, and the sharpness of their angles worn away. 



At Isfield, Little Horsted, Barcombe, WeUingham, &c., the surface of 

 the Weald clay, Iron sand, and Green sand, is covered with beds of gravel? 

 composed of water-worn fragments of sandstone and ironstone, which in 

 some instances are consolidated into a coarse aggregate, and are evidently 

 the detritus of the upper layers of the Iron and Green sand formations. 

 A considerable bed of it occurs in the parish of Barcombe, near the Anchor ; 

 at Hamsey, on the estate of the Eev. Geo. Shiffher; and at WelUngham, 

 near the seat of Mr. John Rickman. 



At Ringmer, and Laughton Place, a layer of loam and ochraceous clay 

 is distributed over the surface of the Blue chalk marl, and frequently con- 

 tains belemnites and other organic remains, that have been washed from 

 the upper beds of that deposit. On the south side of the Downs, to the 

 north- west of Brighton, beds of loam, marl, and clay, with interspersions of 

 gravel, constitute a flat narrow tract of country that extends without in- 

 terruption to Shoreham. 



But the most considerable and important deposit of diluvial detritus in 

 Sussex, is that forming the cliffs at Brighton ; and which possesses charac- 

 ters so remarkable, as to require particular notice. 



