More information : "Deneholes."
"These deep subterranean excavations are to be found on either
side of the Thames. They consist of a narrow well-like shaft
sunk through the overlying Thanet sand, and thence into the
underlying chalk, where a chamber, or series of chambers, is
found.
Their exact period and purpose is not known with certainty but
evidence is available that these pits were already in existence
in the 16 C. William Lambarde writing in 1570 describes some
deneholes in the Dartford area.
The siting of these excavations is often in long-established
woodland and are to be found in association with ancient
earthworks.
In more recent times, many of these denholes have been stopped
up with rubbish, to obviate the danger they presented to
passers-by and animals.
It has been estimated that around the Dartford area alone, some
200 of these pits existed - the greater number of which are now
entirely stopped up.
Excavations similar to deneholes, known as Chalkwells, were
excavated in the 18 C. to provide chalk for 'marling' the
surrounding fields. These wells seldom exceed 25 feet in depth
and consist of three roughly hewn chambers."
"A typical denehole consists of a vertical entrance shaft
approximately 3 feet in diameter sunk through the upper loam
or Thanet Sand until the underlying chalk is reached. The shaft
then widens out into the chalk forming from it a large chamber,
or alternatively a complexity of several chambers all being
inter-connected. The height of the chambers varies between 16 to
24 feet and their width from 5 to 9 feet. The chalk platforms
seen in some chambers are those left by the original excavators.
It is interesting to note that the slope employed in forming the
roof is one which gives a good factor of mechanical safety in
chalk. Rough footholds or toe-grips have been diametrically cut
at approximately 1 foot 6 inches apart to facilitate descent and
these are continued down the shaft to the floor level. The total
depth of the shaft varies between 30 to 80 feet.
The sites chosen for these excavations were often the sides of a
dry valley and they are sometimes found in direct association
with old banks and ditches. Kent and Essex are the classical
sites for these shafts.
Deneholes occur singly and in clusters, typical of the latter
being Cavey Springs, Stankey Wood, Bexley, (TQ 57 SW 58) and
Hangman's Wood, Essex. An interesting point with regard to
deneholes which are in clusters is that considerable care has
been taken to ensure that the chambers of one shaft do not pierce
the chambers of an adjoining shaft.
The Joyden's Wood area formerly contained some 120 of these
shafts, the greater number of which have now fallen in or been
deliberately stopped up. William Lambarde writing in 1570
mentions them in his "Perambulation of Kent". He describes them
as being of antiquity then and mentions the danger they presented
to persons falling into them.
The exact purpose and period of deneholes is not known with
certainty, but from the few that have been excavated both Roman
and Medieval pottery fragments have been found. They are earlier
than the chalk wells with which they bear a superficial
similarity." (1)
Denehole, towards the SE corner of Cavey Spring, at the northern
end of Joyden's Wood, visited July 7, 1883, by the Sidcup & Cray
Field Club. The floor of the chamber was at a depth of 61 feet 6
inches from the surface, and the pit, though small by comparison,
had already reached the pillar stage, two being already formed
and two in process of formation. (2)
No atempt has been made to plan the two denehole clusters (in
the Joyden's Wood area, Bexley,) as the exact distribution did
not seem of sufficient importance to justify the labour involved,
and a check in Cavey Spring showed both Spurrell (a) and the OS
map to be incorrect. (3)
Pit in Joyden's Wood, Bexley, visited November 10, 1883, proved
to be more singular than any yet seen. It is situated near the
eastern margin of the wood, and about 460 yards due east of the
'summerhouse' marked on the 6" Ordnance map. (4)
See Map Diagram for report of some forty deneholes on this sheet.
25" A.M.s corrected. (5)
OS 1:1250 : 1:2500, 1961 checked and amended. (6)
(TQ 50717108) Deneholes (NR) (7)
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