TERTIARY FORMATIONS. 
47 
Tlie strata contained in the Hampshire or Isle 
of Wiglit basin, form five principal divisions, viz. 
1. Lowest marine formation over the chalk, in- 
cluding the plastic clay and sand, together with 
the London clay. 
2. Lowest fresh water formation. 
3. Upper marine formation. 
4. Upper fresh water formation. 
5. Alluvium. 
The remains of the tertiary formations that occur 
in Sussex, admit of the following arrangement ; it 
must, however, be remarked, that from the ruin 
and displacement to which tliey have been exposed, 
it is scarcely possible in every instance accurately 
to determine their geological positions. 
TERTIARY FORMATIONS IN SUSSEX. 
1. Erratic Blocks. 
Boulders of siliceous sand- 
stone, sometimes enve- 
loping pebbles, and form- 
ing a breccia resembling 
that of Hertfordshire. 
Scattered over the 
surface of the 
Downs, near Fal- 
mer, Brighton, 
Lewes, &:c. 
2. London Clay. 
Blue clay containing shells. ■ 
Greenish grey sandstone. < 
Bracklesham, in the 
Isle of Selsea. 
Bognor Rocks ; 
Barn Rocks, be- 
tween Selsea and 
Bognor ; Houn- 
gate, and Street 
Rocks, west of 
Selsea. 
3. Plastic Clay. 
{ 
Beds of clay, marl, sand, 
<S:c. resembling those of ■ 
Woolwich. 
Castle Hill, 
Newhaven ; 
Chimpting 
tie, &c. 
near 
Cas- 
