Journal of Proceedings. cli
there were but two so exceptional as to call for some remark. In one
there were but four chambers, the shaft being on one side; but the plan
was not so fundamentally distinct as it appeared to be at first sight. It
was, indeed, like a Denehole on the ordinary system of excavation in
which the two primary chambers had been formed as usual, while but
two secondary chambers, parallel to each other in direction, had been
made, those generally to be seen opposite not having been begun. In
the other case, one of the primary chambers had been ended off very
sharply only five or six feet from its entrance, progress having been stopped
by a pipe in the chalk, which had let down the Thanet Sand seven or
eight feet below its ordinary level.
As the visitors proceeded on their way, the conductors pointed out
that here and there the makers of the Deneholes had reduced the parti-
tions between the separate pits too much for stability, so that it became
occasionally possible to step through a hole from one pit into another ;
but in all such cases it was evident, from the rounding off and finishing
of the adjoining chambers of the different Deneholes, that the nearness
had been recognised, though its consequences had not been sufficiently
guarded against. An inspection of the ground-plan of the twelve pits
opened out showed that their makers had no scientific means of ascer-
taining the directions of their underground excavations, but, apparently,
hoped to prevent intercommunication by preserving a certain space
between each shaft, and restricting the excavators below to a given area.
They must also have trusted to the acuteness of hearing, and a know-
ledge of the relation between the intensity of the sounds from neigh-
bouring pits, and the thickness of the chalk wall of separation. [For
full particulars and maps, and ground-plan, &c., see " Report on the
Denehole Exploration in Hangman's Wood," 'Essex Naturalist,' vol. i.,
pp. 225-270.]
All present congratulated the Committee, and especially Mr. Holmes
and Mr. Cole, on what had been done in the way of investigation of
these mysterious excavations.
After a thorough inspection of the Deneholes, some of the party,
under the guidance of Mr. Holmes, visited the extensive Chalk Pits
west of Belton Park, Grays, by the kind permission of Messrs. Brooks,
Shoobridge & Co., where excellent exposures of the Chalk and overlying
beds was seen, and the junction between the Chalk and Thames
Valley beds was especially well shown. Mr. Cole stayed at the Deneholes
the whole day looking after the safety of the numerous parties who
were continually arriving and descending the pit. Upwards of eighty,
including many ladies, went down the shaft; but happily, although
some anxiety was felt, not a single hitch occurred during a long and
hard day's work. The seven men employed exercised every possible care ;
the machinery was fixed as before, by Mr. Shipman, Contractor, Grays.
Tea was taken in the " Masonic Hall" attached to the " King's
Arms," Grays ; after which Mr. Holmes explained what had been done