56 THE ESSEX NATURALIST.
facture, and such places are described as Neolithic sites in this
paper. Such sites occur frequently in connection with the gravel
terraces or outcrops, 6ut are by no means confined to such local-
ities. Human artifacts become fewer on the margin of the
Boulder Clay and are usually absent at any considerable distance
from the Chalk outcrop. The Chiswick Hall site is, however,
well within the Boulder Clay and isolated examples of worked
flint may occur on any part of the area.
THE TYPE OF ARTIFACTS FOUND IN THE CAM
VALLEY.
The implements found in this area are mainly referable to
one culture type, the same forms recurring again and again on
the different sites, with occasional exceptions which will be
mentioned later. Among the numerous records of the remains
of Neolithic man in Britain there are several well-marked series,
e.g., the Pebble Industry of the shores, the Microlithic or Pigmy
Industry, the Cissbury and Grimes Graves type, and so forth,
but their chronological sequence is still doubtful. It may,
however, be possible to make some comparison of the material
from the Cam Valley with that obtained from other sources.
Mr. Hazzledine Warren, in a paper on "The Classification
of Pre-historic Remains in Eastern Essex" (6), has recognized
two series of Neolithic remains in that area, an earlier series
possibly extending from Pre-Robenhausian to Robenhausian
times and a later series from Robenhausian well into the early
Bronze period. In the scheme of sequence-dates that accom-
panies this article, he gives the place of (9)40? to (9)50 to the
earlier series and (9)50 to (9)58 to the later series.
Mr. Warren's earlier series appears in many ways to present
affinities with the culture exhibited by the Cam Valley artifacts,
thus the presence of implements allied in form to the grattoir
tarte, the rudeness of the axe forms, the presence of re-worked
polished specimens, and the character of the flakes are points in
common. On the other hand the rarity of arrow heads, and the
presence of abundant examples of prismatic cores in the Cam
Valley, seem to point to a difference in culture which may,
however, be of local significance only. From the examples
illustrated in this article and in the Essex Naturalist (6-7),
and a few specimens from the East of Essex that the writer has