AT HANGMAN'S WOOD, GRAYS. 241
It had been intended to sift the whole of the longest and possibly
one of the other chambers of No. 11, that pit being less filled up with
rubbish than usual. Unfortunately it soon became evident that the
chalk between the mouths of its chambers—where it generally breaks
away much more rapidly than elsewhere—was so shattered and full
of cracks that it would be unsafe to remove the sand and gravel from
that quarter. We were accordingly compelled to content ourselves
with an examination of part only of the floor of the long chamber.
Nothing of importance was found.
Wherever, as before remarked, we exposed the original floor of any
part of a denehole we always found it very smooth and even and nearly
horizontal. It was observable in the open-shafted pits, on the removal
of the mounds, that the deneholes attained their greatest breadth at
a height of 7 or 8 ft. above the floor. In No. 5 the narrowing of the
pit below this height was more strongly marked than usual, and it is
on that account that the area of floor examined seems so narrow in
comparison with the breadth of the pit, as shown in the ground plan,
which gives approximately the greatest length and breadth attained
in each case.
Our last tunnels having introduced us to pits (Nos. 14 and 15)
not more but much less suited to sifting operations than those we
had already entered, and no other open-shafted pit remaining to
form a new centre of work, it seemed best to bring our exploration
to a close. In this view all the members of the Denehole Explora-
tion Committee who visited Hangman's Wood on Saturday, Oct. 8th,
1887, concurred. We have now, in conclusion, but to sum up the
results of our labours, together with the rest of the evidence avail-
able towards settling the question as to the age of these Hangman's
Wood deneholes and the primary purposes of their constructors.
The soft but singularly coherent and easily worked limestone
known as chalk has been much excavated both in ancient and
modern times for a variety of purposes. In addition to open chalk
quarries there exist in many chalk-bearing counties what are known
as chalk-wells, of the construction of which Mr. F. J. Bennett, of the
Geological Survey, has kindly sent us some interesting notes, which
may be read in full in Appendix III. to this Report. Here our
remarks about them shall be as brief as possible. These chalk-wells,
according to Mr. Bennett's experience, exist where the chalk is bare
or covered by other strata to a thickness not exceeding about fifteen
O