87
THE POST - PLIOCENE NON - MARINE
MOLLUSCA OF ESSEX.
By A. S. KENNARD and B. B. WOODWARD, F.L.S.. F.G.S.
With contributions by WILFRED MARK WEBB, F.L.S.
[Read March 6th, 1897.]
IT is doubtful whether any other English county possesses
within its borders so many important and interesting Post-
pliocene deposits as are to be found in Essex. Copford, Clacton,
Ilford and Grays are well known to every geologist ; but besides
these classic localities, there are other less known though equally
interesting deposits : it is certain, too, that there are many others
still waiting for the pick of the geologist to lay bare their secrets.
Such deposits are nearly always of but small extent, and their
presence is quite unsuspected until they are exposed by some
chance excavation. Numerous lists of Mollusca from the various
beds have from time to time been published ; but it has always
been felt that many of these lists are not reliable, and that they
are more likely to lead the student astray than to afford him
assistance. Our knowledge of the English Mollusca has been
greatly increased since the days of the fathers of geology ; several
species have been added to our list, while, on the other hand,
other so-called species have been sunk. Too often the identifi-
cations have been made by persons who were not sufficiently
acquainted with the living forms, and it is certain that that
universal scapegoat, the printer, is responsible for several
incorrect records.
Though these beds and their contained shells are too
often spoken slightingly of by geologists, no one can deny
that accurate lists of the Mollusca must be of great use to
the worker in correlating the various deposits, and would,
moreover, throw new light on many of the obscure problems of
local distribution. It must not, however, be supposed that
accurate identification has been by any means an easy task. It
is well known to every student of Mollusca that the differentiation
of some species is extremely difficult, the microscope having often
to be called into use. With fossil examples this difficulty is, of
course, greatly increased, since the specimens are very often badly
preserved, or may even be mere fragments. Lists, also, have