THE "RED-HILLS" OF CANVEY ISLAND. 51
(b) Pots of similar form, but of varied size, suitable for
the storage of dry food, and, perhaps, for the storage and
transport of salt.
The occurrence of domestic hearths on the sites sunk many
feet below the average spring high tide level of the Estuary
indicates that the surface of the Island at the time of its first
occupation, nearly 2,000 years ago, must have stood 12 to 13
feet above its present level. The relation of the level, at different
periods, of the Red-Hill sites to subsidence in the Thames Estuary
has been made the subject of special study.3 The evidence cannot
be given in detail here, but the following summary and the
two accompanying diagrams will, it is hoped, enable the reader
to appreciate the more important facts relating to the period
under review:—
(1.) The various sites explored have been occupied at
successive periods, and for different purposes, from the early
years of the first century A.D., to the arrival of the Dutch
in the reign of James I.
(2.) Pottery and other objects of mediaeval date are
found commingled with Romano-British pottery of the first
and second centuries on or near the surface of the burnt
earth layer, and are not definitely separated from it by a
layer of alluvium.
(3.) Fire-hearths, which 1,900 years ago must have
stood several feet above the level of the highest spring-
tides (13 ft. above O.D.)4 are now found at a depth 10 ft.
below that level.
(4.) Stratification of the pottery of the Romano-British
period of occupation—both fine and crude—has relation
rather to phases of domestic and industrial activity than
to strict chronological sequence.
(5;) Deposits of coarse clayey silt, suitable for pottery
making are today represented only by shallow layers
in the subsoil at the base of the burnt earth deposit; a
fact consistent with the exhaustion of the raw material
and its replacement by burnt earth at a date prior to the
final evacuation of the site by the Romano-British oc-
cupiers—probably about the close of the 2nd centuty A.D.
3 Proc. Geol. Assoc, vol. LI., 1940, pp. 283-290.
4 O.D. levels throughout this article refer to O.D. Canvey, which is 1ft. 6ins, below O.D.
Liverpool.