A Discovery of Acheulian Implements in the deposits of the Dartford Heath Terrace
A DISCOVERY OF ACHEULIAN IMPLEMENTS IN THE
DEPOSITS OF THE DARTFORD HEATH TERRACE
By P. J. TESTER
SOME of the difficulties involved in considering the age of the Dartford
Heath gravel in relation to other Pleistocene deposits of the Lower
Thames area have been referred to in a previous volume of Arch. Cant.
(LXIII, pp. 128-132). No purpose would be served by repeating what
has already been published in these Proceedings and it will suffice to
say here that there exists a conflict of opinion as to whether the Dartford
Heath gravel is contemporary with the well-known implementiferous
gravels at Swanscombe or earlier. Present evidence is of an uncertain
and somewhat conflicting nature and it will therefore be appreciated
that any new discovery likely to throw light on this problem wfll be of
particular interest to those concerned in elucidating the geological
succession of the Thames Valley deposits and determining the relative
ages of the Stone Age industries they contain.
During 1952 deep excavations have been made on the eastern fringe
of the Dartford Heath terrace in connection with the braiding of a
new Technical CoUege (N.G.I.535738). In the course of this work
several Acheulian biface implements were discovered. The site lies
on the brink of the Darent Valley, the chalk outcropping from beneath
the terrace deposits on the slope eastward towards the river. Unfortunately
the main exposures were obscured by the time my investigations
were made, but I was able to view a typical section exposed in a recently
dug " soak-away," and the clerk of the works, Mr. W. T. L. Scott, to
whose kindness and able assistance I am greatly indebted, furnished
me with photographs of the larger excavations with details of levels
which have enabled me to compile the foUowing account.
In the section examined the surface was approximately 97 O.D.,
beneath which about 1 ft. 6 in. of surface soil rested upon a varying
thickness up to 2 ft. of solifluxion gravel channeUing the beds below.
These consisted of reddish fluviatUe sand merging downwards into a
greyish loam. The workmen reported that below this they encountered
a shaUow bed of coarse material which from their description was of
similar character to the flinty gravel exposed in pits nearer the centre
of the Heath. In the adjoining larger exposures the junction with
the chalk was revealed at 87 O.D. In the " soak-away " section the
thickness of the sand and loam bed was not less than 6 ft.
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ACHEULIAN IMPLEMENTS IN DEPOSITS, DARTFORD HEATH TERRACE
The implements were aU obtained from the sand or loam, a fact
confirmed by traces still adhering to their surfaces when presented
for my inspection. The largest (Fig. 1, No. 1) was found at the depth
of 6 ft. and is unpatinated and unabraded. The butt of another
simflar implement (not fllustrated) was found at the same depth. Both
the other specimens were stated to have come from a somewhat higher
level.
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FIG. 1. Acheulian implements from Dartford Technical College site, (k)
All these implements are sufficiently weU defined typologically
to enable them to be used, for dating the deposits in which they lay,
at least in relation to other sites in the general locality. It may
therefore be stated at once that they belong to the same stage of the
Acheulian culture as that abundantly represented in the Middle
Barnfield (late Boyn HiU) gravel at Swanscombe. Pointed, pearshaped
bifaces of the type of Nos. 1 and 2 are the commonest form in
the Middle Gravel of the Barnfield pit, whole many examples of the
ovate implements represented by No. 3 have come from the upper levels
of Rickson's pit, south of GaUey HiU.
This evidence constitutes proof that this portion of the Dartford
Heath terrace is of Boyn HiU age. It is to be noted also that the
levels, when compared with those at Swanscombe, fall weU within the
range observed in that locality.1
1 King, W. B. R. and Oaldey, K. P., 1936, " The Pleistocene Succession in the
Lower Parts of the Thames Valley," Proc. Preli. Soc, Vol. I I , Part I, p. 59. It is
there stated that the summit of the Swanscombe Middle Gravel is about 115 O.D.
In " Report of the Swanscombe Committee," 1938, J.R. Anthr. Inst., LXVIII,
p. 23, the base of the Swanscombe terrace is noted as 75 O.D.
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ACHEULIAN IMPLEMENTS IN DEPOSITS, DARTFORD HEATH TERRACE
Further down the slope towards the Darent and slightly to the
south, I observed 5 ft. of Coombe Rock, similar to that at Baker's
Hole, overlying the chalk exposed in the sides of a small pit by the
roadside (N.G.I.536736). This agrees with the Swanscombe sequence
where the downcutting of the river after the aggradation of the Boyn
Hill terrace deposits was closely followed by formation of Coombe
Rock resulting from a return of glacial conditions. The solifluxion
gravel overlying the implementiferous sands on the Technical College
site may thus reasonably be correlated with the Upper Gravel in the
Barnfield section.
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