THE " RED HILLS " OF CANVEY ISLAND. 145
If the pots were fired in the open6 or in a furnace made and
broken down after each operation, the front of the firing floor
might have advanced as excavation proceeded at the bank-face,
the abandoned floor in the rear being subsequently covered up by
the waste material produced. This conclusion is in accordance
with facts recorded in the Report of the Exploration Com-
mittee, 1906-7, with respect to excavations made under their
supervision at Langenhoe. On p. 7 they say "The red earth
"had the appearance of soil that had been tipped" and again
p. 8, "Although the red soil varied in parts as regards its texture,
"it had everywhere the same appearance of a rubbish tip."
A similar confusion of strata as regards half-baked clay and
carbonaceous matter was noticeable at the Canvey sites, but it is
a significant fact that the burnt earth material wherever it
rested on a base layer of sandy loam was seen to be heavily
charged with charcoal and burnt clay, and the base layer of
burnt clay at several holes was a hard-burnt lake-red laminated
layer that suggested that here one was in the immediate neigh-
bourhood of an old working floor.
The surface of the waste material, levelled and trodden
down, might have served as a floor for secondary operations—
industrial and domestic, and this may account for what appeared
to be the presence of "secondary floors" occasionally met with
at various points.
Ditches, if they were ever present, seem to have been filled
up with alluvium. Where present on the mainland sites they
may have served to collect rain-water for mixing operations;
salt water would be unsuitable for such a purpose.
6 See Dr. F. Keller, "Lake Dwellings of Switzerland," p. 149, 2nd Edit., 1878, Transl.
by J. E, Lee. Also, Wm. Cole, "Exploration of some Red Hills in Essex," Essex Naturalist,
1906, p. 180.