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THE GEOLOGY OF SOUTH ESSEX.
"The Geology of London, and part of the Thames Valley." By W.
Whitaker, B.A., F.R.S., F.G.S. Two vols. 8vo. Eyre and Spottiswoode,
East Harding Street, Fleet Street, London, 1889.
To all geologists interested in the district around London, Mr.
Whitaker's Geological Survey Memoir on "The Geology of the
London Basin" (1872) has long been familiar, while his smaller
"Guide to the Geology of London" has had a still larger circulation.
It will be well, therefore, in the first place, to define the scope of the
new memoir as compared with that of the larger of the works just
mentioned.
It is stated in the Preface to be a description of the sheets of the
Geological Survey Map, Nos. 1, 2, and 7, with some marginal parts
of Nos. 6 and 8. The "Geology of the London Basin" included,
in addition, sheets 12, 13, and part of 34. It was styled "Vol. IV.,
Part 1" of the Memoirs of the Geological Survey, because it was
intended that Part 2 should consist of a description of the superficial
beds of the district, Part 1 treating only of the Chalk and the Eocene
deposits. But Part 2 has never been published, while Part 1 will
not be reprinted, and the new memoir describes both the older and
the superficial deposits of the more restricted area, districts not
included in it being covered by smaller memoirs dealing with single
sheets of the Geological Map. I may remind readers of the Essex
Naturalist that the whole of the southern half of Essex, together
with a small portion of north Kent, and the borders of Middlesex
and Hertfordshire, are comprised in sheets 1 and 2, No. 7 being
westward of No. 1, and containing parts of Middlesex, Hertfordshire,
Buckinghamshire, and Berkshire. Sheet 6 is mainly West Kent, and
sheet 8 Surrey. We have thus in Mr. Whitaker's new memoir a full
description both of the older and of the more superficial formations
of Essex south of a line drawn from the mouth of the estuary of the
Blackwater on the east to the river Lea, in the neighbourhood of
Hoddesdon, on the west.
The first volume, of 567 pages, contains the geological description
of the district; the second, of 355 pages, consists wholly of details of
sections. Those of wells of various localities predominate in number,
but no less than thirty-six pages are occupied by trial-borings made
by the Metropolitan Board of Works for the great main drainage
works, and for other purposes. For these Mr. Whitaker was indebted