272 CORRELATION OF THE PREHISTORIC "FLOOR."
district, I have minutely examined some twenty-five or thirty
miles of sections, at frequent intervals, during a period of six
years. This work has enabled me to amplify the details
previously given in several respects. As I must necessarily refer
to this district as a standard of comparison, it will be well to
give the full details here.
9. Present salting surface.
8. Tidal-silt, or Scrobicularia-clay, with Red-Hill briquetage.
7. Peat.
6. Buried Prehistoric surface with Flint Implements and Pottery
[the "Lyonesse" surface].
5. Grey Marsh Clay.
4. Rainwash with Flint Implements and Pottery.
3. Pleistocene (?) Brickearth, containing occasional erratics.
2. Layer of shattered Septaria
I. Grey Marsh Clay with Elephas primigenius.
O. London-clay.
It must be understood that this full succession is not seen
in its completeness at any one point. Like all geological succes-
sions, whether on a large scale or on a small one, it must be
pieced together from evidences that are somewhat scattered
and fragmentary.
The pieces of Red-Hill briquetage that were found in situ
in the Scrobicularia-clay (No. 8) were tying in its upper part,
not far from the margin of the marsh, at a spot where the Buried
Prehistoric Surface was rising up to the side slope of the valley
and the Scrobicularia-clay only about two feet six inches or
three feet in thickness. It is therefore a little uncertain to
what level in that clay it might belong in the more central parts
of the channels. I think it most probable that it would still
belong to the upper part.
The Rainwash (No. 4) is found chiefly at or near the foot of
the valley slopes, it is not so much seen in the more central parts
of the channels. The Grey Marsh Clay (No. 5) seems to succeed
the Rainwash horizontally, in going towards the central parts
of the channels, and as it is probably contemporary with the
Rainwash, the two are bracketed together in the table. I
have not succeeded in finding any remains in this bed. Still
further towards the centre of the channels, at least so far as the
Hamford Water is concerned, both these beds, and also the
Pleistocene (?) Brickearth below, are cut out, and the Buried
Prehistoric Surface rests directly on the line of shattered Septaria.