View source for Denehole

{{Short description|Type of chalk cave in England}}
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[[File:Denehole.jpg|thumb|Descending into a denehole in [[Essex]]]]
A '''denehole''' (alternatively '''dene hole''' or '''dene-hole''') is an underground structure consisting of a number of small [[chalk]] caves entered by a vertical shaft. The name is given to certain caves or excavations in [[England]], which have been popularly supposed to have been created by the [[Danes (Germanic tribe)|Danes]] or some other of the early northern invaders of the country. The common spelling '''Dane hole''' is adduced as evidence of this, and individual names, such as [[Vortigern]]'s Caves at [[Margate]], and [[Canute]]'s Gold Mine near [[Bexley]], naturally follow the same theory. The word, however, is probably derived from the [[Old English language|Anglo Saxon]] ''den'', a hole or valley.<ref name="EB1911"/> The lack of evidence found in them has led to long arguments as to their function.

==Form==
The general outline of the formation of these caves is invariably the same. The entrance is a vertical shaft some 3 feet (1 m) in diameter falling, on an average, to a depth of 60 feet (20 m). The depth is regulated by the depth of the [[chalk]] layer from the surface, although chalk can be found within a few feet, or even inches, from the surface. A depth of from 45 to 80 feet or more, is a characteristic feature.<ref name="EB1911"/>

Footholds were cut into the sides of the shaft to allow people to climb in and out. The shaft, when the chalk is reached, widens out into a domed chamber with a roof of chalk some 3 feet thick. The walls frequently contract somewhat as they near the floor. As a rule the main chamber is 16 to 18 feet in height, beneath each shaft. From this excessive height it has been inferred that the caves were not primarily intended for habitations or even hiding-places.<ref name="EB1911"/> In most cases, between two and four sub-chambers are present, excavated laterally from the floor level, the roof being supported by pillars of chalk left standing.

==Distribution==
There are many underground excavations in the south of England, also found to some extent in the [[English Midlands|Midlands]] and the north, but true deneholes are found chiefly in those parts of [[Kent]] and [[Essex]] along the lower banks of the [[Thames]]. With one exception there are no recorded specimens farther east than those of the [[Grays Thurrock]] district, situated in [[Hangman's Wood]], on the north, and one near Challock on the south side of the river south of Faversham. Isolated specimens have been discovered in various parts of Kent and Essex, but the most important groups have been found at Grays Thurrock, in the districts of [[Woolwich]], [[Abbey Wood]] and Bexley, and at Gravesend. Those at Bexley and Grays Thurrock are the most valuable still existing. It is generally found that the tool work on the roof or ceiling is rougher than that on the walls, where an upright position could be maintained.<ref name="EB1911"/>

==History==
[[Pliny the Elder]] wrote about British [[Chalk mining|chalk extraction]] in A.D. 70, and archaeological evidence shows that at least some of the deneholes were being exploited during prehistory. Casts taken of some of the pick-holes near the roof show that, in all probability, they were made by bone or horn picks. Numerous bone picks have been discovered in Essex and Kent. These pick-holes are amongst the most valuable data for the study of deneholes, and have assisted in fixing the date of their formation to pre-Roman times. However, very few artifacts which would provide [[Dating methodology (archaeology)|dating evidence]] or assisted in determining the uses of these prehistoric excavations have been discovered in any of the known deneholes. [[Chrétien de Troyes]] has a passage on caves in Britain which may have reference to deneholes, and tradition of the 14th century treated the deneholes of Grays as the fabled gold mines of Cunobeline (or [[Cymbeline]]) of the 1st century.<ref name="EB1911"/>

In 1225 [[Henry III of England|Henry III]] gave every man the right to sink a [[marl]] pit on his own land. Spreading chalk on the fields was a common practice in the [[Middle Ages]]. This appears to have continued into the 19th century. The need for chalk in agriculture supports the theory that the origin of deneholes was for chalk extraction.{{citation needed|date=July 2015}}

[[Margate Caves|Vortigern's Caves]] at [[Margate]] are possibly deneholes which have been adapted later for other purposes; and excellent examples of various pick-holes may be seen on different parts of the walls. The [[Shell Grotto, Margate|Shell Grotto]] in Margate may also have been adapted from a denehole.<ref name=":0">{{Cite web |last=LeGear |first=R. F. |date=2006 |title=The Margate Shell Grotto |url=https://www.kentarchaeology.org.uk/papers/the-margate-shell-grotto |access-date=2025-11-05 |website=Kent Archaeological Society |language=en-GB}}</ref>

Local tradition in some cases suggests the use of these caves by [[smuggler]]s. Illicit traffic was common not only on the coast but in the Thames as far up the river as [[Barking Creek]]. The theory is at least plausible that these ready-made hiding-places, which were difficult of approach and dangerous to descend, were used in this way.<ref name="EB1911"/>

==Purpose==
[[File:Information sign about the Dene Hole in Capstone Park - geograph.org.uk - 1014969.jpg|thumb|information sign about the Dene Hole in [[Capstone Farm Country Park]]]]
By the end of the nineteenth century, three purposes had been suggested for which deneholes may have been originally excavated:

* as hiding-places or dwellings,
* as storehouses for grain, or
* as draw-wells for the extraction of chalk for agricultural uses.

For several reasons it is unlikely that they were used as habitations, although they may have been used occasionally as hiding places.  Silos, or underground storehouses, are well-known in southern [[Europe]] and in [[Morocco]]. It has been suggested that grain was stored unthreshed and carefully protected from damp by straw. A curious smoothness of the roof of one of the chambers of the Gravesend twin-chamber denehole has been put forward as additional evidence in support of this theory.<ref name="EB1911"/>

Since the 1950s the theory that they were ancient chalk mines has gained acceptance. This was formerly thought unlikely, as it was reasoned that chalk could have been obtained outcropping close by. [[J.E.L. Caiger]] worked in Kent excavating, surveying and researching deneholes, and concluded that they were excavated in prehistoric, Roman, medieval and even post-medieval times in order to produce a supply of unpolluted chalk to spread on fields for the purposes of [[agricultural lime|marling]]. By excavating a narrow shaft the miners used up as little  of the productive agricultural land as possible. He suggested various other practical matters that supported his ideas, including the facts that opencast chalk extraction would require moving the material further than necessary and that shallower chalk deposits have much of their minor mineral content leached out by groundwater.

==References==
{{reflist|refs=
<ref name="EB1911">{{EB1911|inline=1 |wstitle=Dene-holes |volume=8 |pages=19-20 |first=Alexander |last=Philip}} References cited:
* ''Essex Dene-holes'' by T. V. Holmes and W. Cole
* ''The Archaeological Journal'' (1882)
* The ''Transactions'' of the Essex Field Club
* ''Archaeologia Cantiana'', &c.
* ''Dene-holes'' by F. W. Reader, in ''Old Essex'', ed. A. C. Kelway (1908)</ref>
}}

==Further reading==
*[[Flaxman Charles John Spurrell|F.C.J. Spurrell's]] paper "Deneholes and Artificial Caves with Vertical Entrances", published in the ''Archaeological Journal'' for 1881 and 1882.
*"Deneholes" Harry Pearman (1966) Chelsea Spelaeological Society Records Vol. 4 72pp
* [[Dorothy L. Sayers]], ''[[The Nine Tailors]]'', 1934.  (Body found in a denehole.)

==External links==
{{commonscat|Deneholes}}
* [https://web.archive.org/web/20060510184213/http://www.kurg.org.uk/sites/deneholes.htm Kent Underground Research Group page on deneholes]
* [http://www.rainham-history.co.uk/articles/dene_holes.htm Rainham Kent Dene Hole Photos from 1980s]
* [https://www.bbc.co.uk/news/uk-england-essex-20626908 Collapse of Denehole in Grays]

[[Category:Archaeology of the United Kingdom]]
[[Category:Types of monuments and memorials]]
[[Category:Subterranea of the United Kingdom]]
[[Category:Subterranean London]]