266 CORRELATION OF THE PREHISTORIC "FLOOR."
II.—THE BURIED PREHISTORIC SURFACE AND THE
SUBMERGED FORESTS.
A prehistoric surface buried beneath the marsh lands, with
an associated peat, is widely distributed not only in Essex, but
also in Lincolnshire, Somersetshire, and elsewhere. It is not
infrequently accompanied by a forest growth, and it then
forms the familiar "submerged forests" of our coasts. The
forest, however, is not always present, and is in no way an
essential part of the phenomenon. It is very commonly seen
at a level of about two to five feet above low water mark, but
it passes out of sight below this line, descending to the deeper
parts of the submerged river valleys.
To what depth the surface inhabited by prehistoric man
may thus descend, I have not been able to ascertain positively..
The deep excavations for the clocks at Barry in South Wales1
and at Grimsby- have brought to light peat beds at depths of
fifty or fifty-five feet below high water mark, and at forty feet
below high water mark at Liverpool,3 but no evidence of human
occupation has yet been obtained from these depths. It is
not improbable that it may yet be found.
The lowest recorded depth at which any prehistoric remains
have been found comes from the Southampton Docks.4
These were found in a thick bed of peat filling up an old river
channel, and not in the more usual position of the former dry
land surface beneath the peat. These remains consist of flint
flakes, and a perforated stone hammer. The latter is stated
to have been found near the bottom of the peat, at a depth
of about twenty feet from the surface [which is presumably
the salting surface] but the conditions under which it was found
are not quite clear to me, and it does not appear to have been
found in place by a scientific observer. But even taking this
depth as strictly reliable, it is not much below the surface as
seen on the shore at the lowest tides.
It has already been stated that the usual position in which
prehistoric remains are found associated with the submerged
forests is on the former dry land surface beneath the peat
1 A. Strahan, Quart. Journ. Geol. Soc., vol. iii. (1896), p. 474.
2 S. V. Wood, jun., and Rev. J. L. Rowe, Quart. Journ. Geol. Soc., vol. xxiv. (1868),
p. 157.
3 T. Mellard Reade, Proc. Liverpool Geol. Soc. (1871-2), p. 36.
4 T. W. Shore and J. W. Elves, Papers and Proc. Hants Field Club, vol. i. (1889), p. 43.