Miscellanies. 163 
fresh water origin ; while in others they are marine. Now it is ob» 
vious’that the strata which contain marine bodies only, must have 
_ been deposited under very different circumstances to those which 
contain fresh water fossils ; hence we have two natural divisions— 
namely, the marine, and the fresh water formations. The chall, 
and the sands and marls associated with it, belong to the former ; 
the weald clay, and the sand and sandstones of the interior of the 
country, to the latter. The subordinate divisions of the strata refer 
principally to their mineralogical characters. ‘There are also beds 
of gravel, sand, and clay, containing boulders, &c. the debris of the 
regular deposits, and which, although of vast antiquity, are of far more 
recent origin than those on which they repose ; these contain bones 
and teeth of large terrestrial quadrupeds. 
The strata are grouped, and named as follows, beginning with the 
uppermost or newest bed. 
Alluvium.—The silt, clay, sand, gravel, &c. formed by the rivers 
now in action. Lewes Levels afford a familiar example. 
Diluvium.—Sand, gravel, &c. containing the debris of older for- 
mations, bones of the horse, elephant, deer, whale, &c. The cliffs 
between Brighton and-Rottingdean are diluvial. Z 
Tertiary Strata.—These consist of regular beds of sand, clay, &c. 
resting on the chalk, and are characterised by their organic remains. 
Castle Hill, at Newhaven, Bognor Rocks, Clay at Bracklesham, are 
examples of these strata. 
Chalk Formation.—This comprises, 
1. The chalk, with and without flints ; it forms the Sussex, Hamp- 
shire, Surrey, and Kent Downs. 
2. Grey marl, forming the base of the Downs, and generally ap- 
pearing on the weald escarpment of the chalk ; at Hamsey, Stone- 
ham, and Southerham there are marl pits, where the usual fossils 
occur. : = ae 
3. Galt,* or blue chalk marl, a stiff blue clay; its fossils have 
their shells beautifully preserved. It is seen at Ringmer, near 
Lewes; and on the road-side from Wannock stream to Eastbourn ; 
at Newtimber it appears under the grey marl. 
4. Shanklin Sand, so called from Shanklin Chine, in the Isle of 
Wight, where it is beautifully exhibited. This sand forms hills, that 
rival the Downs in altitude in the west of Sussex ; near Lewes it oc- 
* A provincial term, used in Cambridgeshire. © i 
