268
NOTES ON ESSEX GEOLOGY.
This is now alluded to because, although no classification of the
Drift beds was given (either in the paper or elsewhere), I was
disposed to regard those beds as belonging to the lower division
of the Glacial Drift, that is as being older than what is generally
known as the Great Chalky Boulder Clay. P. G. H. Boswell,
however, as the result of much good work in the eastern counties,
regards the various infillings of such channels (as at Sudbury
and the opposite part of Essex) as belonging rather to the Boulder
Clay.
I have never liked the name given to that clay : it is certainly
great ; but, as far as I know, other Boulder Clays are just as
chalky. As a rule adjectives are awkward things in geologic
nomenclature, and I have generally been content to honour
this particular clay as the Boulder Clay, leaving the various
other and much smaller beds of like character in the position of
poor relations, more or less without a local habitation or a name.
Since this date further sections have given further proof
of this channel.
B. B. Woodward's long paper on "Pleistocene Non-marine
Mollusca,"4 deals with those from the. Alluvium at the Royal
Albert Dock, Tilbury Dock, and the Lea Valley at Walthamstow,
and from the River-Drift at Grays, West Thurrock, and Ilford,
with notes on some of the species and a full list.
In his "Notes on Pleistocene Sections in and near London"
W. J. Abbott describes a section5 at West Thurrock (pp.
476-478) which, however, is wrongly given as four miles west
of Grays, being really less than three. It shows the Drift
banked up against a chalk-cliff (not escarpment as it is termed).
The precise site is not given ; but the author is not right in
suggesting that no section (of the kind) so far west had been
published : it may be that it is really the same as one of the
two described in 1889 in the Geology of London, etc., vol. i, p.
418, which work apparently the author had not seen. He gives
more details, however.
C. Reid's monograph on the "Pliocene Deposits,"6 is of
course chiefly concerned with other counties, Essex being
specifically referred to only on pp. 82-85 and in most of the
voluminous lists of fossils. Of the Upper Crag he says:—
4 Proc. Geol. Assoc., Vol. xi., No, 8, p. 335, etc.
5 Ibid., p. 473, etc.
6 Geological Survey Memoir, pp. viii., 326, 5 plates.