70 THE PAST AND FUTURE OF THE ESSEX FIELD CLUB.
those counties which ignored the superficial beds, whatever might be
the case elsewhere. Therefore I need only say now that the drift
maps of Essex should be in the hands of all who are interested in its
agriculture, underground water supply, and the distribution of its
animals and plants, as well as in its geological structure. And by
the geologist the survey maps should be looked upon rather as a
sound basis for further work than as obviating any need for his
labours. Any geological map must vary in completeness as the
amount of evidence at the disposal of the surveyor varies. In Essex
the general geological structure of the county is very simple, but the
accurate mapping of the various beds in detail is often a task of
some difficulty, both from their uniformly soft character and their
variability. But geological maps must be coloured, and each forma-
tion limited by boundary lines, whatever may be the amount of
available evidence. Insufficient evidence, too, may not only cause
the existence of inaccurate boundary lines, but of erroneous notions
as to the relation of the beds to each other. Thus, the sections seen
by the geological surveyor may not have led him to suspect the
existence of an unconformity between two beds, while a section
exposed years after his departure may make it at once manifest. In
some instances he may have been guided by evidence no longer
available, but, on the other hand, it must necessarily have happened
that since his departure new wells have been sunk, new brick yards
and gravel pits opened, and new railways and road-cuttings made.
This new evidence may turn out to be important or unimportant,
but it is, at all events, most desirable that our geological members
should not omit to notice and record its true nature.
The geological papers that have hitherto appeared in our "Transac-
tions," though not numerous, have been useful additions to our
knowledge. The most important as regards the amount of informa-
tion it affords is that by Mr. W. Whitaker, on "Some Essex Wells,"
which I trust may be but the first of a series. I have pleasure in
adding that my friend and former colleague has lately been making
an exhaustive bibliographical list of books and papers bearing more
or less on the geology of Essex, which will shortly appear in the
Essex Naturalist. Of the merits of our special memoir on the
Essex Earthquake, by Prof. Meldola and Mr. W. White, I need say
nothing here.
As our botanical largely outnumber our geological members, we
find, as might be expected, that our botanical papers and notes