4
PRE-HISTORY IN ESSEX.
Rayleigh Hills (A. E. Salter, E.N., xiv., 1907, p. 267).
Eolith from the high level gravels. 8
Obscured Interment (E.N., xv., 1908, p 146). Dr. A. E.
Salter found a portion of a skeleton in a pit on One Tree
Hill (Laindon Hills). It was found 6 feet from the surface
in Bagshot Sand and showed no evidence of disturbance
or of the existence of a grave. The lesson from this is
sufficiently obvious, and needs no comment. 9
III.—Relation of Palaeolithic and Glacial Deposits.
In considering this problem, we should always hold in mind
the influence of the pre-Glacial undulations of the land on which
the drift lies, and also the anomalies of glacial erosion. We
must be prepared for striking irregularities, particularly in the
case of those narrow, deep, drift-filled channels which never
possessed an outlet to the sea corresponding with their own
depth and are essentially of the nature of lake-basins.
Cam Valley (W. Whitaker, E.N., iii., 1889, pp. 140-2 ; iv.,
1890, p. 117 ; ix., 1895, p. 169). Such a drift-filled channel
has been proved by borings at Newport, Wenden, and
Littlebury. At the former place, 340 feet of drift has
been proved (140 feet below O.D.), without touching the
bottom. As the country rock is chalk, there can be no
doubt of the accuracy of this conclusion. 10
Kelvedon (G. F. Beaumont, E.N., i., 1887, p. 189). Another
similar channel, reaching a depth of 194 feet (106 feet
below O.D.), may exist here. Contributory evidence [12]
supports the accuracy of this conclusion, although in itself
it rests largely upon the interpretation of the well-sinkers'
descriptions. The record speaks of 194 feet of "blue
clay, stone, and chalk" over-lying "blue Clay." It is
assumed that the former is all true Boulder Clay, although
the London Clay contains much Septarian material, which
might be described as "stone and chalk" by a non-
geologist. 11
Blackwater Valley (W. H. Dalton, T. & P., ii., 1881, p. 15 ;
E.N., iv., 1890, p. 104). In the higher reaches, the Boulder
Clay forms only the top of the plateau between the Guith
and the Blackwater. Between Feering and Witham, it
has descended into the valley and has cut through the
Glacial gravel deeply into the London Clay, but does not
rise far on to Tiptree ridge. The Pleistocene Valley gravel,
about Kelvedon and Witham, overlies this Boulder Clay. 12
Kelvedon-Tollesbury, visit to new railway (E.N., xiii.,