MOLLUSCA OF PLEISTOCENE DEPOSITS AT CLACTON. 29
later epoch of emergence than the Clacton channel stage, possibly
to the period of the Buried Channel of the Thames.
Coming to later times, the land stood much higher than it
does to-day during the Mesolithic period, which is dated to about
5000 to 4000 B.C., this continued through the Neolithic to the
Beaker Stage of about 2000 to 1800 B.C. Shortly after this,
submergence set in again, but this was not completed at the time
of the Late Beaker Dutch invasion of about 1600 to 1500 B.C.
This was succeeded by a notable submergence represented by the
Scrobicularia-clay, followed after an interval by a re-emergence
of the land and an occupation of the marshes during the Roman
Period.
THE MOLLUSCA OF THE PLEISTOCENE
DEPOSITS AT LION POINT, CLACTON.
By A. S. KENNARD, A.L.S., F.G.S.
(Read Feb. 27th, 1932.)
THE material on which the following notes are founded has
been obtained from three sources, a series sent by S.
Hazzledine Warren, F.G.S., a small number of examples col-
lected by Derek Richardson and a series obtained by myself
when under the guidance of Mr. Warren, I visited the section
last year. Being a foreshore section it is difficult to ascertain
the exact sequence, but it would appear there are two fossili-
ferous beds, the bottom bed a shelly sand decidedly iron-stained
and an upper bed of white shelly sand. In the upper part of this
bed the marine form Cardium edule Linn, was found. The beds
are clearly true river deposits ; land shells are scarce and usually
broken. The bottom bed yielded the greater number of the
recorded species. I do not think that the Unios had lived on the
spot, for the valves were always separate. Many of the shells
had apparently been drifted some distance and had suffered
during the journey. Some of the shells were thickly coated with
lime, in that respect resembling the shells from the High Terrace
of the Thames at Swanscombe. I may add that I have seen
nothing resembling this shelly sand in the many dredgings
from the present Thames that I have examined though this may
arise from selective dredging.