268 THE ESSEX NATURALIST.
and the onset of glaciation. It must be remembered, however,
that the lower glacial deposits in East Anglia are for the most
part not represented in Essex, whose glacial record, therefore,
starts later than that of East Anglia. We are, therefore, not
necessarily justified in inferring a Pre-Pleistocene age for the
platform. The division between the Pliocene and the Pleisto-
cene series is at best somewhat arbitrary, and there is little
practical difference between a late Pliocene and an early Pleisto-
cene age. General indications, however, derived from other
districts, would favour the former alternative. It is also
significant that the 200-ft. platform shows a species of comple-
mentary relation to the pre-glacial sands and shingles of Eastern
Essex included by Prestwich in his "Westleton Beds." These
beds first appear east of Dunmow and Braintree, where the
platform begins to warp over into the East Anglian depression
and if, as is probable, the beds are marine, the relation is
suggestive. It would seem that a late Pliocene sea transgressed
westward concurrently with the downwarping of the platform.
The only other considerations bearing on the problem of
age are of a somewhat speculative nature, depending upon the
existence of a series of raised-beaches, typically developed in
the Mediterranean, but extending over a wide area. Amongst
them is a well-marked raised-beach at about 200 ft. (the
Milazzian beach). This beach must be represented by an inland
base-level in the regions where it occurs. It may seem, at first
sight, a far cry from the Mediterranean to Essex, but the view
that Pliocene and Pleistocene "uplifts" were due to eustatic
(i.e., uniform) shifts of sea-level, controlled by the imprison-
ment of water in the growing ice-sheets, is gaining ground, and
has a weight of cumulative evidence behind it. The Milazzian
raised-beach is variously correlated by British authorities with
the Weybourn Crag or the Leda Myalis Bed. That the 200-ft.
platform is to be correlated with the Milazzian raised-beach is
a proposition whose possibility is not to be gainsaid, though as
yet it lacks definite proof. In any case, no considerable error
is involved in regarding the 200-ft. platform as marking the
end of Pliocene time in Essex.