Burnt mound
Encyclopedia
A burnt mound is an archaeological feature
consisting of a mound of shattered stones and charcoal
, normally with an adjacent hearth and trough. The trough could be rock-cut, wood-lined or clay-lined to ensure it was watertight. Radiocarbon dates
vary quite widely, the earliest being late Neolithic, with clusters of dates between 1900 - 1500 BC and 1200 - 800 BC, with some outliers in the Iron Age
. There are also some dates that go into the early Medieval period. The technology used at burnt mounds has much greater antiquity and is found from the palaeolithic onwards.
when the heated stones were dropped into liquid, normally believed to be water. The mound is assumed to result from the periodic clearing out of the trough, with the stone fragments and charcoal being cast up into a mound. The mound is frequently a crescent shape, which is seen as being the result of the upcast.
. Recognised from the nineteenth century onwards, they attracted little significant interest until the 1980s. In Ireland they are often found in low-lying ground close to water. In Britain, they appeared to have a distribution pattern confined to the higher ground. However, this may be illusory, as examples have been found at lower altitudes during linear route excavations. The reason that they had not been recognised previously was that the mounds have been ploughed out, although the trough may partially survive and there will be layers of the burnt mound material surviving as a spread of material. The mixture of burnt and shattered rock with charcoal, labelled as burnt mound material, is found on occasion without the trough. There are settlement sites on Orkney, where the burnt mound material is found as thick layers
, but there is no trough to explain the shattering of the rocks.
The upland bias in distribution in Britain has led to a suggestion that they were cooking sites for hunting parties, and there are images from Medieval Irish texts that appear to show this. There are also descriptions of the use of such features for cooking in some of the early Medieval tales, although the historicity of these accounts is open to question. The burnt mounds are always adjacent to water courses, and there can be several instances along the same burn or stream.
There has been considerable debate about the time required to create the mounds. Some interpretations posit the rapid accumulation of material, as a trough was used intensively and very frequently; others suggest a slower accumulation, where the trough was used occasionally over a long period of time. The hunting site explanation would most likely result in the latter pattern of accumulation, while the former would suggest that the use of the trough was for an essentially domestic purpose.
of cooking. The process undoubtedly works; experiments were carried out in Ireland in the 1950s to show that a joint of meat could be fully cooked in about three to four hours through this method. However, bone is rarely if ever reported from burnt mound sites, which would be unusual for a cooking site. This has been explained as the result of the soils being too acidic for the bone to be preserved, but this is unsatisfactory. It would be rather unlikely that all of the soils relating to burnt mounds were so acidic that no bone survived, particularly as the pH of the soil will vary considerably from site to site. However, there are examples of burnt mounds that have been recorded on neutral or basic soils, without bone being apparent in the burnt mound material, Alternatives that have been suggested include saunas (where the intention is to create steam rather than cook anything), fulling, salt production
, leather preparation etc.
The implication found in many accounts of burnt mounds in Britain gives the impression that they are found in Ireland and Scotland, but they also are found in Wales and in England. The Welsh examples tend to be upland and rural, as are many of the English ones, but there are also many found in the lowlying English Midlands
. Barfield & Hodder's interpretation of burnt mounds as potentially saunas arose from their various excavations of burnt mounds in the Birmingham area, while more recently forty mounds have been discovered in Birmingham
. One example is in Moseley Bog
where experiments were made in the late 1990s to asses the plausibility of the sauna hypothesis.
, such as in Sweden
and Switzerland. It is not necessarily the case that the burnt mound material must have been created for the same purposes, and it would be a mistake to seek a single explanation for all the examples of burnt mounds and burnt mound material. Similar material has been produced all over the world
, and there may be a range of explanations.
Feature (archaeology)
Feature in archaeology and especially excavation has several different but allied meanings. A feature is a collection of one or more contexts representing some human non-portable activity that generally has a vertical characteristic to it in relation to site stratigraphy. Examples of features are...
consisting of a mound of shattered stones and charcoal
Charcoal
Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...
, normally with an adjacent hearth and trough. The trough could be rock-cut, wood-lined or clay-lined to ensure it was watertight. Radiocarbon dates
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
vary quite widely, the earliest being late Neolithic, with clusters of dates between 1900 - 1500 BC and 1200 - 800 BC, with some outliers in the Iron Age
Iron Age
The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...
. There are also some dates that go into the early Medieval period. The technology used at burnt mounds has much greater antiquity and is found from the palaeolithic onwards.
Purpose
The shattered rock fragments are thought to be the remains of stones heated in fires, which were used to heat water for cooking, bathing, dyeing or leather treatment. The shattering of the rock appears to have been the result of thermal shockThermal shock
Thermal shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity, and high thermal expansion coefficients...
when the heated stones were dropped into liquid, normally believed to be water. The mound is assumed to result from the periodic clearing out of the trough, with the stone fragments and charcoal being cast up into a mound. The mound is frequently a crescent shape, which is seen as being the result of the upcast.
Locations
The vast majority of burnt mounds are found in the uplands of Britain, and in Ireland where they are called fulachtaí fiaFulacht fiadh
A fulacht fiadh is a type of archaeological site found in Ireland. In England, Scotland, Wales and the Isle of Man they are known as burnt mounds. They commonly survive as a low horseshoe-shaped mound of charcoal-enriched soil and heat shattered stone with a slight depression at its centre showing...
. Recognised from the nineteenth century onwards, they attracted little significant interest until the 1980s. In Ireland they are often found in low-lying ground close to water. In Britain, they appeared to have a distribution pattern confined to the higher ground. However, this may be illusory, as examples have been found at lower altitudes during linear route excavations. The reason that they had not been recognised previously was that the mounds have been ploughed out, although the trough may partially survive and there will be layers of the burnt mound material surviving as a spread of material. The mixture of burnt and shattered rock with charcoal, labelled as burnt mound material, is found on occasion without the trough. There are settlement sites on Orkney, where the burnt mound material is found as thick layers
, but there is no trough to explain the shattering of the rocks.
The upland bias in distribution in Britain has led to a suggestion that they were cooking sites for hunting parties, and there are images from Medieval Irish texts that appear to show this. There are also descriptions of the use of such features for cooking in some of the early Medieval tales, although the historicity of these accounts is open to question. The burnt mounds are always adjacent to water courses, and there can be several instances along the same burn or stream.
There has been considerable debate about the time required to create the mounds. Some interpretations posit the rapid accumulation of material, as a trough was used intensively and very frequently; others suggest a slower accumulation, where the trough was used occasionally over a long period of time. The hunting site explanation would most likely result in the latter pattern of accumulation, while the former would suggest that the use of the trough was for an essentially domestic purpose.
Possible explanations
The main explanation for burnt mounds is that they were cooking sites. However, there are problems with such explanations, not the least of which is the lack of any direct evidenceDirect evidence
Direct evidence supports the truth of an assertion directly, i.e., without an intervening inference...
of cooking. The process undoubtedly works; experiments were carried out in Ireland in the 1950s to show that a joint of meat could be fully cooked in about three to four hours through this method. However, bone is rarely if ever reported from burnt mound sites, which would be unusual for a cooking site. This has been explained as the result of the soils being too acidic for the bone to be preserved, but this is unsatisfactory. It would be rather unlikely that all of the soils relating to burnt mounds were so acidic that no bone survived, particularly as the pH of the soil will vary considerably from site to site. However, there are examples of burnt mounds that have been recorded on neutral or basic soils, without bone being apparent in the burnt mound material, Alternatives that have been suggested include saunas (where the intention is to create steam rather than cook anything), fulling, salt production
Edible salt
Salt, also known as table salt, or rock salt, is a mineral that is composed primarily of sodium chloride , a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities, but is harmful to animals and plants in excess...
, leather preparation etc.
The implication found in many accounts of burnt mounds in Britain gives the impression that they are found in Ireland and Scotland, but they also are found in Wales and in England. The Welsh examples tend to be upland and rural, as are many of the English ones, but there are also many found in the lowlying English 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...
. Barfield & Hodder's interpretation of burnt mounds as potentially saunas arose from their various excavations of burnt mounds in the Birmingham area, while more recently forty mounds have been discovered in Birmingham
Birmingham
Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London, with a population of 1,036,900 , and lies at the heart of the West Midlands conurbation, the second most populous urban area in the United Kingdom with a...
. One example is in Moseley Bog
Moseley Bog
Moseley Bog is a nature reserve in the Moseley area of Birmingham in England, at .It was once a secondary reservoir to feed the millpond of Sarehole Mill. Although now drained, the embankment on its eastern side remains...
where experiments were made in the late 1990s to asses the plausibility of the sauna hypothesis.
Burnt mounds outside Britain
Burnt mound material is also found outside Britain, and examples have been found elsewhere in northwestern EuropeNorth-West Europe
North-West Europe is a term that refers to a northern area of Western Europe, although the exact area or countries it comprises varies.-Geographic definition:...
, such as in Sweden
and Switzerland. It is not necessarily the case that the burnt mound material must have been created for the same purposes, and it would be a mistake to seek a single explanation for all the examples of burnt mounds and burnt mound material. Similar material has been produced all over the world
, and there may be a range of explanations.