PALAEOLITHIC AND NEOLITHIC IMPLEMENTS. 47
are drawn downwards, while the London Clay below is drawn
upwards to fill the pipe. These appear to be due to some
foreign object, possibly the trunk of a tree, embedded in the
gravel during its formation. The gravel beds would then
founder downwards, and the London Clay below would be
squeezed upwards, to fill the vacancy left as the object decayed.
I have not yet succeeded in finding any Palaeolithic implements
along this cliff-section. Unless any late Palaeolithic (that is,
Post-Mousterien) remains occurred here, which is not very
likely, implements would probably be somewhat scarce, and
derived from earlier drifts.
With regard to the Recent Deposits of the marshes, I have
not yet cleared up all points of difficulty and uncertainty, but at
fairly frequent intervals during the past few years I have
examined the sections along the coast and up the inlets, and find
the following to be the invariable order in which the beds
occur:—
8. Present condition of things: Red-Hills, Romano-British remains, etc.
7. Period of depression;—Scrobicuiaria-Clay.
6. Traces of a peaty layer.
5. Buried Prehistoric Surface, with (Late Neolithic or Early Bronze Age ?)
flint implements and pottery. This passes below the level of low tide.
4. Brown Clay, probably a hill-wash, with Neolithic implements and
pottery.
3. Late Pleistocene (?) Brickearth.
2. Layer of Septarian nodules.
1. London Clay.
These beds (including the Buried Prehistoric Surface) are
traceable over considerable areas, and are not merely lenticular
patches. Bed number 4 is, however, found chiefly at the foot of
the valley slopes; it is difficult to trace it in the more central
parts of the present tidal channel. This is what one would
expect to be the position of a hill-wash.
There is no doubt that these beds represent a definite
succession of events in the recent geological history of the
country, in fact, practically the same succession is found also in
the fen deposits of the Lincolnshire coast. The greatest
difficulty in working out this succession has been in the most
important part of it, namely in reference to the beds 4 and
5, containing the two series of implements. One is not often so
fortunate as to find well finished implements in situ in undis-