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NOTES ON THE GEOLOGY OF MALDON AND
THE BLACKWATER ESTUARY.1
By T. V. HOLMES, F.G.S., M.A.I., Vice-President, E.F.C.
[Read September 15th, 1889.]
On the occasion of our visit to Langdon Hills, in June last, we were
fortunate enough to secure the services of Mr. Whitaker as Director,
and his unsurpassed knowledge of Essex geology was placed at our
disposal with his usual generosity and geniality. But it unfortunately
happens that the meeting of the British Association, and other causes,
have prevented him and other workers in this district from promising
to act as our geological guides to-day. Consequently I consented, at
the request of Mr. Cole, to make a few geological remarks myself, and
to illustrate them by means of the maps and sections of the Geological
Survey. However, I do not propose to say anything about the Black-
water Valley in connection with the singular contortion met with in
the Wickham Bishops well, which has been discussed by Mr. W. H.
Dalton and the late Searles V. Wood (Trans. E. F. C, vol. ii, p. 15,
and vol. iv, p. 82). Nor shall I touch upon the details of the interesting
section exposed by the railway cutting on the west side of this town,
some account of which has already been given in the Essex Natura-
list (see vol. i, p. 149, and vol. ii, 236), as full details of it appear in
a memoir by Mr. Whitaker, now passing through the press.2 But I
shall confine myself mainly to those aspects of the geology of the
estuary which explain the antiquity and long-continued existence of
the town of Maldon.
Before discussing the purely local geology, a few general remarks
may be of service. At first sight the Drift Maps of this county present
an appearance somewhat revolting to the lover of simplicity, and
startling to him whose knowledge of Essex geology has been derived
from a general geological map of England and Wales. On further
examination, however, the order of sequence becomes more or less
manifest. The Chalk, the lowest of Essex formations, though it
comes to the surface only between Purfleet and East Tilbury, and in
the north-west corner of the county, underlies the whole of the inter-
mediate district, and is the main source of the water supply from
1 This paper was kindly prepared by Mr. Holmes for the the meeting at Maldon, on September
14th and 15th, 1889 (see Essex Naturalist ii, p. 251), but owing to want of time it was
"taken as read" on that occasion.—Ed.
2 Now published by the Geological Survey under the title of the "Geology of London and Part
of the Thames Valley," vols. i and ii. London : Stanford, 1889.—Ed.