Primaeval Man in the Valley of the Lea. 117
under and upheaving the "floor" with its implements; the
Hackney Brook is towards the south, and a flooded brook to
the south would hardly up-
heave the "floor" from the
north; a is a mass of London-
clay and sand brought from a
distance and pushed under
the "floor" by the advancing
"trail'' from the north. Where
the "floor" has been crum-
pled and disturbed the im-
plements show a very small
amount of abrasion; when the
"floor" is covered by the
stratified sand or mud of the
river, the tools are all as
sharp as on the day they were
made.
It fortunately happens that
very near the sections here
illustrated, vix., at 270 yards
west by north from Clapton
Railway Station, and just
south of Caroline Street
(marked on Stanford's map),
one or two other cuttings have
quite recently been made;
these show admirable sections
of characteristic "trail." At
fig. 7 a section facing south
is engraved to scale; and at
fig. 8 the end of the section is
further enlarged to show the
"trail" and "warp" above,
and the stratification below.

Fig. 7.
The section is 11 ft. 6 in. deep,
and just reaches the top of the stratum of gravel which
contains implements intermediate in age between those of