26
THE ESSEX NATURALIST.
But grafted upon the Clactonian technique the High Lodge
industry possesses the Mousterian finish.
On the other hand, the French Mousterian, which is the
pure Mousterian properly so called, has, as Prof. Breuil has
pointed out to me, its basic affinities with the Levallois rather
than with the Clactonian10.
The more detailed study of the Lower Palaeolithic is still
in the infant school. I think we may be sure of this : namely,
that we can no longer place all the different flint industries into
one simple sequence of evolution. We must feel our way to
seek a more complex basis of interpretation of the facts, and in
this endeavour our Clactonian industry is taking a foremost
place.
At least it would appear to be clear that the Clactonian-
High Lodge sequence is an independent line of evolution in part
contemporary with the sequence that we formerly called
Strepyan-Chellian-Acheulian.
Physical History of the Pleistocene Extension of the River
Thames.
It would appear that during the stage of the gravels of Boyn
Hill and of Dartford Heath the extended Thames wandered over
a mature and wide base-level, now represented by the plateau
of the Frinton district which lies between the levels of 70 and
S5 feet above O.D. The accompanying Palaeolithic industry
is represented by the "Oldest Class" of Worthington Smith.
It may be that we have gravels that lie between the levels
of say 45 and 60 feet above O.D. that correspond with the
lower gravel of Swanscombe with the heavily flaked early form
of the Clactonian industry.
At some time after the Frinton gravels had been laid down
an epoch of emergence supervened, which resulted in rejuvena-
tion of the river and a vigorous deepening of its valley.
We cannot ascertain the maximum elevation during this
stage, but I have waded out into the sea at low tide and dug up
the purely freshwater deposit of the Clacton channel from as
deeply under water as I could conveniently reach : this must
be about 8 or 10 feet below O.D. Now the river-bed gravel
underlying the later Taplow Terrace deposit of West Thurrock
10 In my own collection I am now calling the High Lodge and Stoke Newington floor industry
the "Clactonio-Mousterian" to indicate the affinities of its technique, however these affinities
may have arisen.