174
THE ESSEX NATURALIST.
would appear that we have to face the fact that in the celebrated
channel at Grays (Little Thurrock) the down-cutting went as low
as 10 O.D. at this time. The obvious association of this with the
Clacton channel 20 or 30 feet lower is probably correct. [Warren,
1923, 1940.]
It may be helpful to recall that the freshwater deposits of
Clacton are overlaid by silts of marine origin up to at least
30 O.D. This submergence checked the flow of the river up-
stream and resulted in an aggradation of deposits so that the
Grays channel became a "buried channel."
As aggradation continued it would seem that the Furze Platt
gravels, previously mentioned, were built up to nearly 100 O.D.
The fossils prove a very close association between Grays, Clacton,
and Swanscombe, but I think for more precise relative dating
one must look to the human industries. In this connection it
is noteworthy that the "middle gravel" of Swanscombe yields
a Clactonian that is intermediate between the Clacton II of the
name site and Clacton III (=High Lodge).
On the border of our region the Furze Platt gravel occupies
a considerable area in Leytonstone, from which I have obtained
the characteristic industry ; the extensive gravels of S. Essex will
be referred to under the "50-foot Terrace."
The Stoke Newington Sands.—These are found between the
levels of 50 and 90 O.D., and include the "Palaeolithic Floor"
of Worthington Smith [1894] with its Clacton III industry,
which was formerly thought to be Mousterian. We now realise
that the latter is quite a distinct industry of later date, which
absorbed much of the Clacton III tradition The "Floor" itself,
which is the former flood-plain, is laterally inclined from the
side of the valley towards the river more steeply than the longi-
tudinal gradient of the terrace.
The 50-Foot Terrace.—There is a break in the lateral
continuity of the Pleistocene river gravels at about 50 O.D. in our
region, and at the same height above the river further up-stream.
This constitutes a natural physical subdivision, and I think it is
well to retain the time-honoured name for those numerous
deposits, whose exact relative dating is uncertain.
I have a large collection of implements from S. Essex, par-
ticularly Barkingside, Becontree Heath, Dagenham and the
surrounding country. They are from gravels mapped as Boyn
Hill, Taplow and Flood Plain, and cover a range of level from
10 to over 100 O.D. Most of these are of Early Palaeolithic
character, which might have come from gravels of the Dartford
Heath stage. Even the gravels that are presumed to be the latest
contain many of these early derivatives. Dr. Ince has proved at