Denehole
Encyclopedia
A Denehole 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 be due to the 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 Canutes Gold Mine near Bexley
, naturally follow the same theory. The word, however, is probably derived from the Anglo Saxon
den, a hole or valley. The lack of evidence found in them has led to long arguments as to their function.
from the surface, but, although chalk could have been obtained close at hand within a few feet, or even inches, from the surface, a depth of from 45 to 80 feet, or more, is a characteristic feature.
Footholds were cut into the sides of the shaft to allow the miners 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. 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.
, also found to some extent in the 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 Rochester on the south side of the river. 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.
wrote about British chalk extraction in 70AD 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 evidence
or assisted in determining the uses of these prehistoric excavations has been discovered in any of the known deneholes. Chrétien de Troyes
has a passage on underground 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.
In 1225 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.
Vortigerns 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.
Local tradition in some cases suggests the use of these caves by smugglers. 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.
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 the south of Europe
and Morocco
. It has been suggested that the 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.
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 marl
ing. By excavating a narrow shaft, the miners used up as little of the productive agricultural land as possible. He suggested various other practical issues which supported his ideas including that open cast 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.
Another theory that has been advanced is that the excavations were made in order to get flint
s for implements.
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, which have been popularly supposed to be due to the 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
Vortigern
Vortigern , also spelled Vortiger and Vortigen, was a 5th-century warlord in Britain, a leading ruler among the Britons. His existence is considered likely, though information about him is shrouded in legend. He is said to have invited the Saxons to settle in Kent as mercenaries to aid him in...
s Caves at Margate
Margate
-Demography:As of the 2001 UK census, Margate had a population of 40,386.The ethnicity of the town was 97.1% white, 1.0% mixed race, 0.5% black, 0.8% Asian, 0.6% Chinese or other ethnicity....
, and Canutes Gold Mine near Bexley
Bexley
Bexley is an South East London]] in the London Borough of Bexley, London, England. It is located on the banks of the River Cray south of the Roman Road, Watling Street...
, naturally follow the same theory. The word, however, is probably derived from the Anglo Saxon
Old English language
Old English or Anglo-Saxon is an early form of the English language that was spoken and written by the Anglo-Saxons and their descendants in parts of what are now England and southeastern Scotland between at least the mid-5th century and the mid-12th century...
den, a hole or valley. 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, obviously, by the depth of the chalkChalk
Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....
from the surface, but, although chalk could have been obtained close at hand within a few feet, or even inches, from the surface, a depth of from 45 to 80 feet, or more, is a characteristic feature.
Footholds were cut into the sides of the shaft to allow the miners 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. 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 EnglandEngland
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, also found to some extent in the Midlands
English Midlands
The Midlands, or the English Midlands, is the traditional name for the area comprising central England that broadly corresponds to the early medieval Kingdom of Mercia. It borders Southern England, Northern England, East Anglia and Wales. Its largest city is Birmingham, and it was an important...
and the north, but true deneholes are found chiefly in those parts of Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
and Essex
Essex
Essex is a ceremonial and non-metropolitan county in the East region of England, and one of the home counties. It is located to the northeast of Greater London. It borders with Cambridgeshire and Suffolk to the north, Hertfordshire to the west, Kent to the South and London to the south west...
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 Rochester on the south side of the river. 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
Woolwich
Woolwich is a district in south London, England, located in the London Borough of Greenwich. The area is identified in the London Plan as one of 35 major centres in Greater London.Woolwich formed part of Kent until 1889 when the County of London was created...
, Abbey Wood
Abbey Wood
Abbey Wood is a district of South-East London, England, located mostly in the London Borough of Greenwich, and partly within the London Borough of Bexley. It is situated east of Charing Cross.-Development:...
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.
History
Pliny the ElderPliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
wrote about British chalk extraction in 70AD 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 evidence
Dating methodology (archaeology)
Dating material drawn from the archaeological record can be made by a direct study of an artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence relative to datable contexts...
or assisted in determining the uses of these prehistoric excavations has been discovered in any of the known deneholes. Chrétien de Troyes
Chrétien de Troyes
Chrétien de Troyes was a French poet and trouvère who flourished in the late 12th century. Perhaps he named himself Christian of Troyes in contrast to the illustrious Rashi, also of Troyes...
has a passage on underground 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
Cymbeline
Cymbeline , also known as Cymbeline, King of Britain or The Tragedy of Cymbeline, is a play by William Shakespeare, based on legends concerning the early Celtic British King Cunobelinus. Although listed as a tragedy in the First Folio, modern critics often classify Cymbeline as a romance...
) of the 1st century.
In 1225 Henry III
Henry III of England
Henry III was the son and successor of John as King of England, reigning for 56 years from 1216 until his death. His contemporaries knew him as Henry of Winchester. He was the first child king in England since the reign of Æthelred the Unready...
gave every man the right to sink a marl
Marl
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...
pit on his own land. Spreading chalk on the fields was a common practice in the Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
. 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.
Vortigerns 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.
Local tradition in some cases suggests the use of these caves by smugglers. Illicit traffic was common not only on the coast but in the Thames as far up the river as Barking Creek
Barking Creek
Barking Creek joins the River Roding to the River Thames. It is fully tidal up to the Barking Barrage, which impounds a minimum water level through Barking in Barking. In the 1850s, the creek was home to England's largest fishing fleet, and the Victorian icehouse - where the fish were landed and...
. 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.
Purpose
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
- storehouses for grain.
- drawwells 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 the south of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
. It has been suggested that the 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.
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 marl
Marl
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...
ing. By excavating a narrow shaft, the miners used up as little of the productive agricultural land as possible. He suggested various other practical issues which supported his ideas including that open cast 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.
Another theory that has been advanced is that the excavations were made in order to get flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...
s for implements.
Further reading
- "Essex Dene-holes" by T.V. Holmes and W Cole; The Archaeological Journal (1882); the Transactions of the Essex Field Club; Archaeologia Cantiana. &c.;
- "Deneholes" by F. W. Reader, in Old Essex, ed. A. C. Kelway (1908).
- F.C.J. Spurrell'sFlaxman Charles John SpurrellFlaxman Charles John Spurrell , the archaeologist, geologist and photographer, was born in Mile End, Stepney, London, the eldest son of Dr. Flaxman Spurrell, M.D., F.R.C.S., and Ann Spurrell...
paper "Deneholes and Artificial Caves with Vertical Entrances", published in the Archaeological Journal for 1881 and 1882.