In archaeology, earthworks are artificial changes in land level,
typically made from piles of artificially placed or sculpted rocks and
soil. Earthworks can themselves be archaeological features, or they
can show features beneath the surface.
Earthworks of interest to archaeologists include hill forts, henges,
mounds, platform mounds, effigy mounds, enclosures, long barrows,
tumuli, ridge and furrow, mottes, round barrows, and other tombs.
Hill forts, a type of fort made out of mostly earth and other natural
materials including sand, straw, and water, were built as early as the
Stone Age and were built more frequently during the Bronze Age
Iron Age as a means of protection. See also Oppidum.
Henge earthworks are those that consist of a flat area of earth in a
circular shape that are encircled by a ditch, or several circular
ditches, with a bank on the outside of the ditch built with the earth
from inside the ditch. They are believed to have been used as
monuments for spiritual ritual ceremonies.
A mound is a substantial manmade pile of earth or rocks that was
frequently created to mark burial sites 
Platform mounds are pyramid or rectangular-shaped mounds that are used
to hold a building or temple on top.
An effigy mound is a pile of earth, often very large in scale, that is
shaped into the image of a person or animal, often for symbolic or
spiritual reasons 
An enclosure is a space that is surrounded by an earthwork.
Long barrows are oblong-shaped mounds that are used for burials.
A tumulus or barrow is a mound of earth created over a tomb.
A cross dyke or cross-ridge dyke is a bank and ditch, or sometimes a
ditch between two banks, that crosses a ridge or spur of high ground.
Found in Europe and often belonging to the later
Bronze Age or Iron
Age. Often marked on
Ordnance Survey maps in the UK.
Ridge and furrows are sets of parallel depressions and ridges in the
ground formed primarily through historic farming techniques.
Mottes are mound structures made of earth and stone that once held
castles. They are an important part of the motte-and-bailey castle, a
castle design during early Norman times in which the castle is built
on the motte, and surrounded by a ditch and a bailey, which is an
enclosure with a stone wall.
A round barrow is a mound that is in a rounded shape that was used
Neolithic times as a burial mound.
Geoglyph, a large design or motif
Earthworks can vary in height from a few centimetres to the size of
Silbury Hill at 40 metres (130 ft). They can date from the
Neolithic to the present. The structures can also stretch for many
tens of kilometres (e.g.
Offa's Dyke and Antonine Wall). In area, they
can cover many hectares; for example, Maiden Castle, which is 19
hectares (47 acres).
Shallow earthworks are often more visible as cropmarks or in aerial
photographs if taken when the sun is low in the sky and shadows are
more pronounced. Similarly, earthworks may be more visible after a
frost or a light dusting of snow.
Earthworks can be detected and plotted using Light Detection and
Ranging (LIDAR). This technique is particularly useful for mapping
small variations in land height that would be difficult to detect by
eye. It can be used to map features beneath forest canopy and for
features hidden by other vegetation.
LIDAR results can be input into a
geographic information system (GIS) to produce three-dimensional
representations of the earthworks.
A survey of a Hopewell enclosure
Newark Earthworks in Ohio, U.S.
An accurate survey of the earthworks can enable them to be interpreted
without the need for excavation. For example, earthworks from
deserted medieval villages can be used to determine the location,
size, and layout of lost settlements. Often these earthworks can point
to the purpose of such a settlement, as well the context in which it
Mound in Ohio
Earthworks in North America include mounds built by Native Americans
known as the
Mound Builders. Ancient people who lived in the American
Midwest commonly built effigy mounds, which are mounds shaped like
animals (real or imaginary) or people. Possibly the most famous of
these effigy mounds is Serpent Mound. Located in the Ohio, this
411-meterlong earthen work is thought to memorialize alignments of the
planets and stars that were of special significance to the Native
Americans that constructed it. Cone-shaped or conical mounds are
also numerous, with thousands of them scattered across the American
Midwest, some over 80 feet tall. These conical mounds appear to be
marking the graves of one person or even dozens of people. An
example of a conical mound is the Miamisburg
Mound in central Ohio,
which has been estimated to have been built by people of the Adena
culture in the time range of 800 B.C. to 100 AD. The American
Plains also hold temple mounds, or platform mounds, which are giant
pyramid-shaped mounds with flat tops that once held temples made of
wood. Examples of temple mounds include Monks
Mound located at the
Cahokia site in Collinsville, Illinois, and
Mound H at the Crystal
River site in Citrus County, Florida. The earthworks at Poverty
Point occupy one of the largest-area sites in North America, as they
cover some 920 acres (320 ha) of land in Louisiana.
Military earthworks can result in subsequent archaeological
earthworks. Examples include Roman marching forts which can leave
small earthworks. During the American Civil War, earthwork
fortifications were built throughout the country, by both Confederate
and Union sides. The largest earthwork fort built during the war
was Fortress Rosecrans, which originally encompassed 255 acres
(103 ha).[relevant? – discuss]
In northeastern Somalia, near the city of
Bosaso at the end of the
Baladi valley, lies an earthwork 2 km to 3 km long.
Local tradition recounts that the massive embankment marks the grave
of a community matriarch. It is the largest such structure in the
wider Horn region.
Bigo is an extensive earthworks site located in the interlacustrine
region of southwestern Uganda, Africa. Situated on the south shore of
the Katonga river, the
Bigo earthworks consist of a series of ditches
and berms comprising an outer arch that encompasses four
interconnected enclosures; when combined the
Bigo earthworks measure
more than 10 kilometers long. Radiometric dates from
archaeological investigations at
Bigo date the earthworks to roughly
AD 1300 - 1500, and they have been called Uganda's "largest and most
important ancient monument."
The Steppe Geoglyphs, discovered in 2007 using Google Earth, are an
example of Earthworks in Central Asia.
An 11th-century hill fort: Bielsko-Biała, Poland
A 12th-century motte-and-bailey castle:
Château de Gisors
Château de Gisors in Eure,
An Adena tumulus (burial mound): Grave Creek
Mound in West Virginia,
A Mississippian platform mound:
Cahokia in Illinois, U.S.
Mound at Ocmulgee National Monument
Fort Ancient effigy mound: Serpent
Mound in Ohio, U.S.
Neolithic long barrow:
Stoney Littleton Long Barrow
Stoney Littleton Long Barrow in Somerset,
Thornborough Henges in North Yorkshire, U.K.
^ Muir, 77
^ Wood, 85–96; see also: excavation
^ Scott, Willie. "How Earthwork Forts were Built". Retrieved 13 April
^ "The Definition of a Henge". Retrieved 13 April 2012.
^ "Mound". Retrieved 13 April 2012.
^ "Platform Mound". Retrieved 13 April 2012.
^ "Effigy Mound". Retrieved 13 April 2012.
^ "Enclosure". Retrieved 13 April 2012.
^ "West Kennet Long Barrow". Retrieved 13 April 2012.
^ "Tumulus". Retrieved 13 April 2012.
^ Darvill, Timothy (2008). Oxford Concise Dictionary of Archaeology,
2nd ed., Oxford University Press, Oxford and New York, p. 116.
Ordnance Survey 1:50,000 Landranger series.
^ "Ridge and Furrow". Retrieved 13 April 2012.
^ "Motte". Retrieved 13 April 2012.
^ "Round Barrow". Retrieved 13 April 2012.
^ Wilson, 38
^ Aston, 14
^ EID; crater beneath canopy
^ Taylor, 59–60
^ Feder, 54
^ Crystal, Ellie. "Mounds of North America". Retrieved 12 April
^ Feder, 54
^ Weisman, Brent (1995). "Crystal River: A Ceremonial
Mound Center on
Florida Gulf Coast".
Florida Archaeology. 8: i–86.
^ Kidder, Tristram R.; Ortmann, Anthony L.; Arco, Lee J. (November
Poverty Point and the
Archaeology of Singularity", Society for
Archaeology Archaeological Record, 8 (5): 9–12
^ Earl J. Hess (2005). "Field Armies and Fortifications in the Civil
War". UNC Press. Retrieved 20 May 2013.
^ Ed Bearss (1960). "Fortress Rosecrans Research Report". National
Park Service. Retrieved 17 May 2013.
^ Hodd, Michael (1994). East African Handbook. Trade & Travel
Publications. p. 640. ISBN 0844289833.
^ a b Ali, Ismail Mohamed (1970).
Somalia Today: General Information.
Ministry of Information and National Guidance, Somali Democratic
Republic. p. 295.
^ Sutton, John (2000). "Ntusi and Bigo: Farmers, cattle-herders and
rulers in western Uganda, AD 1000-1500". Azania: Archaeological
Research in Africa.
^ Posnansky, Merrick (1969). "
Bigo Bya Mugenyi". The Uganda
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