68 
THE CRETACEOUS ROCKS OF BRITAIN. 
2. Eastern Sussex. 
Having defined Western Sussex as that part which lies between 
Hampshire and the valley of the Adur, we have now to follow the 
Lower Chalk through the remaining part, which lies between the 
Adur and the coast near Eastbourne, a distance of about 30 miles 
along the outcrop. 
Eastern Sussex contains many classical localities for Lower Chalk 
fossils, but no one has collected from them since the establishment 
of zones and of a definite Middle Chalk (except along the coast) ; 
consequently we do not yet know the exact age of many of 
Mantell’s types. It is to be hoped that some geologist will arise in 
Sussex who will follow in Mantell’s footsteps, and collect carefully 
from the successive zones, so as to ascertain the range of all the 
fossils which have been figured by Mantell and Dixon. 
The general succession of the beds in Eastern Sussex is similar 
to that in the western part of the country. There is a certain 
thickness of soft grey chalk-marl above the basement-bed, but its 
upper limit does not coincide with that of the Am. varians zone, for 
that species is found above it. The zone of Holaster subglobosus 
consists of the usual blocky chalk, grey below but lighter above, 
and nearly white below the Belemnite Marls, which in the coast 
section have the unusual thickness of about 15 feet. 
A.—Inland Exposures. 
The following information is taken from notes by Mr. Eeid : — 
Between the river Adur and the Devil’s Dyke the outcrop of the 
Lower Chalk is very narrow, and most of the roads down the steep 
slopes of the escarpment expose sections. Most of these cuttings 
show Chalk Marl overlain by grey chalk. 
Clayton tunnel on the London and Brighton Bailway traverses 
the greater part of the Lower Chalk, for Chalk Marl is seen at its 
northern end, and the cutting at the south end shows the Belem¬ 
nite Marl overlain by Melbourn Bock. 
Massive greyish chalk, belonging to the middle part of the Lower 
Chalk, is seen in the quarry of the Clayton Limeworks. 
The highest part of the Lower Chalk is exposed in a quarry near 
Plumpton, five miles west of Lewes. The following note of the 
section was taken by Mr. W. Hill in 1897 
Middle 
Chalk. 
Lower 
Chalk. 
ft. 
W 
t H 
<D 
+■2 
jo 
'"3 
cq 
\ 
(Hard rough nodular much-broken chalk— 
Inoc. mytiloides and Rhynch. Cuvieri 
(.Smooth, hard white chalk - 
'Marly chalk ------- 
Hard whitish-grev marly chalk 
A strongly-marked band of dark grey marl 
Firm greyish marly chalk - 
Bed of dark grey marl, but not so strongly 
marked as that above ----- 
Firm grey marly chalk with conchoidal fracture, 
passing gradually to firm massive whitish 
l chalk - -- -- -- - 
Firm massive whitish chalk - , - seen for 
25 
1 
0 
1 
0 
0 
0 
4 
25 
in. 
0 
9 
8 
0 
o 
6 
3 
6 
0 
