THE ESSEX FIELD CLUB. 263
evidence, not even a tradition. It is, of course, hard to prove a negative ; but
the argument of Messrs. T. E. and R. H. Forster, who surveyed the caves,
that they are planned exactly like a coal mine of the early eighteenth century,
indicates what is probably the earliest date of any working here. This argument
is not seriously impugned by the letter of "Historicus" in these columns,
where he asks for plans or views of the Newcastle mine. A coal mine may be
visited without much difficulty, if its general character is not familiar ; but a still
nearer resemblance can be seen in the chalk mines now being worked a few miles
away. The Druidical theory is based entirely on surmise ; there are facts
proving that the Chislehurst Caves were a chalk mine within the memory of man;
and nothing to suggest, but everything to render extremely unlikely, that they
were ever anything else. Mr. Clift demonstrated most convincingly that the
alleged prehistoric camp on the hill above the caves is a pure myth.
It may be added that the hollow sound referred to by a correspondent in these
columns, as indicating that deeper chambers probably exist at one spot under
the present galleries, is in all likelihood quite illusory. One is often misled by
the acoustics of underground chambers ; and there have been many instances at
Cheddar and elsewhere of cave-owners who have wasted money in excavating on
the track of such hollow reverberations and found nothing but solid rock.
A hearty vote of thanks was accorded to Mr. Nichols for his valuable services
in arranging the meeting, who confined his reply to a narrative of the deeds of
certain smugglers in the caves during the last two centuries. The party enjoyed
their visit to these picturesque excavations, which are of considerable interest as
a curious subterranean labyrinth, apart from the romantic legend that has grown
up round them during the last seven years."
[The two appended short papers by Mr. A. L. Leach and Mr. T. V. Holmes
embody much information which was brought forward at the meeting.—Ed.]
A KENTISH CHALK MINE.
By A. L. LEACH.
SO much attention has recently been directed to the Chislehurst "Caves"
and the improbable theories associated with them, that an account of a
visit paid in February, 1903, to a Kentish Chalk-mine may serve to complete the
disillusionment of those who have been beguiled into a half-hearted belief in their
"antiquity"
Chalk has some obvious uses, "whitening" and lime for mortar, for instance,
but tens of thousands of tons of chalk have been excavated entirely for use in the
making of bricks—the familiar yellow London "stock brick," which owes its
colour, in part, to the finely-divided chalk added to the brick-earth in the
mixing roil], and this chalk is obtained from true mines sunk sometimes nearly
too feet below the ground level.
Obviously brick-making can be most economically conducted when the raw
materials, chalk and "brickearth," are in close association. This is the case
in certain parts of Kent where chalk underlies, at no great depth, beds of sandy
clay, which are admirably suited for brick-making. The brickfield and its
associated chalk mine1 with which this article deals lies in a small valley, and a
1 See Proc. Geol. Assoc, Vol. xix. Report of Excursion to East Wickham and Bostal
Heath, April 28th, 1906, by A. L, Leach and B. C. Polkinghorne B.Sc.