File:The Quarterly journal of the Geological Society of London (12961035625).jpg

78
PKOCEEDINGS OF THE GEOLOGICAL SOCIETY.
which, according to Dr. Blackmore, are associated with, flint instru-
ments of the Amiens type.
Land and freshwater shells are very-
abundant. The great shell-bed is near
the chalk, lying upon a bed of gravel ;
and the Pupa-bed touches the lower sur-
face of the covering bed of gravel, e.
While the curve of the surface is on the
average 3° between A and B, the dip of
the lower gravel, 6, where it touches the
escarpment of the chalk, will probably
lie at a very steep angle.
The Pupa-bed, c, a fine loess, is marked
by a distinct band of colour ; it is about
2 ft. thick, and slopes to the river in a
gentle curve. I have marked its dip
16°, then 11°, then 9°. The bed c con-
tains only six species of shells, Helix
arhustorum (?), Helix hispida, Zua lu~
brica, Lymnoea palustris, Yalvata pisci-
nalis,Pisidium obtusale, besides the Pupce
in immense abundance. The lower band
h contains thirty-one species of terres-
trial and fluviatile shells, according to the
lists of the late Mr. John Brown and Dr.
Blackmore.
The chalk, a, is 30 feet from the sur-
face at A, but in 30 yards it reaches the
surface ; so that the escarpment in the
part not yet opened is known to be at
an angle of 30°, sloping towards the
river. As is usual, the brick- earth is
thickest a little way from the escarpment,
and passes, on the same horizon, into
gravel and sand as you approach the
river.
The remains of another arctic mammal
(the Musk-Ox) have been recently found
in the loess at Salisbury. This animal
is now living in a remote part of North
America. The stratification at Salis-
bury, shown in fig. 9, is very similar to
that at Erith, fig. 17.
The mammalian gravel and Combe rock extends from Brighton,
without interruption, to the point drawn, fig. 10, and presents a clifi"
of roughly stratified beds facing the sea, about 60 ft. in height.^
The escarpment of the chalk is known to be not far distant in the
rear of the present face of the cliffs at any point ; and an extensive