THE "RED HILLS" OF CANVEY ISLAND. 147
The character of the operations carried on at Canvey, as that
of the mainland sites, must remain a matter of conjecture. All
one can say at present is that the geographical position of the
sites and the character of the mounds is consistent with their
having been occupied during the Romano-British period for the
following purposes:—
1. The manufacture of crude red pottery.
2. The use of such pottery on the site for the manufacture
of salt by evaporation of sea-water, and
3.8 The curing and salting of fish caught in the Estuary.
It is very problematical whether any kind of crude ware was
made for domestic use on the site and elsewhere, but a few rims
of more massive and specialised character have been found in
the burnt earth.
Operations at the various sites were no doubt seasonal,
as at brickfields to-day. Clay would be moulded and fired in
the summer months, clay dug and sea-water evaporated in the
cooler and moister seasons. At Canvey there seems to have been
actual occupation of the sites throughout the year. In cases
where sites were only in seasonal occupation where did the workers
live?
Perhaps I may here be allowed to quote from a very illumini-
nating paper by Dr. A. G. Francis on the "Subsidence of the
Thames Estuary since the Roman Period at Southchurch, Essex"
(Essex Naturalist, vol. xxiii., 1929-32). In discussing the
geographical conditions existing in the Thames Estuary and the
probable location of the early settlements prior to the arrival of
the Romans, he says:—
"In this locality two areas only were free from heavy forest
"growths and were suitable for settlement in the post-Pliocene
"period:—
"(a) The Bagshot sands on the hills west of Southchurch,
"covered by heath and light birch woods;
"(b) Pleistocene gravel patches, the remains of the river
"terraces, with open tree growth and light scrub.
"These areas alone could be cleared without much labour for
"the erection of huts and the formation of trackways. On
8 I am indebted to Mr. M. R. Hull, Curator of the Colchester Museum for this suggestion.