Vitrified fort
Encyclopedia
Vitrified fort is the name given to certain crude stone enclosures whose walls have been subjected in a greater or lesser degree to the action of fire
. They are generally situated on hills offering strong defensive positions. Their form seems to have been determined by the contour of the flat summits which they enclose. The walls vary in size, a few being upwards of 12 feet (3.7 m) high, and are so broad that they present the appearance of embankments
. Weak parts of the defence are strengthened by double or triple walls, and occasionally vast lines of rampart
s, composed of large blocks of unhewn and unvitrified stones, envelop the vitrified centre at some distance from it.
No lime
or cement
has been found in any of these structures, all of them presenting the peculiarity of being more or less consolidated by the fusion of the rocks of which they are built. This fusion, which has been caused by the application of intense heat, is not equally complete in the various forts, or even in the walls of the same fort. In some cases the stones are only partially melted and calcined; in others their adjoining edges are fused so that they are firmly cemented together; in many instances pieces of rock are enveloped in a glassy enamel-like coating which binds them into a uniform whole; and at times, though rarely, the entire length of the wall presents one solid mass of vitreous substance.
It is not clear why or how the walls were subjected to vitrification. Some antiquarian
s have argued that it was done to strengthen the wall, but the heating actually weakens the structure. Battle damage is also unlikely to be the cause, as the walls must have been subjected to carefully maintained fires to ensure they were hot enough for vitrification to take place.
Since John Williams, one of the earliest of British geologist
s, and author of The Natural History of the Mineral Kingdom, first described these singular ruins in 1777, about fifty examples have been discovered in Scotland
. The most remarkable are:
For a long time it was supposed that these forts were peculiar to Scotland; but they are found also in County Londonderry
and County Cavan
, in Ireland
; in Upper Lusatia
, Bohemia
, Silesia
, Saxony
and Thuringia
; in the provinces on the Rhine, especially in the neighbourhood of the Nahe
; in the Ucker Lake
, in Brandenburg, where the walls are formed of burnt and smelted brick
s; in Hungary
; and in several places in France
, such as Châteauvieux, Péran, La Courbe, Sainte Suzanne, Puy de Gaudy and Thauron. They have not been found in England
or Wales
.
Glass transition
The liquid-glass transition is the reversible transition in amorphous materials from a hard and relatively brittle state into a molten or rubber-like state. An amorphous solid that exhibits a glass transition is called a glass...
. They are generally situated on hills offering strong defensive positions. Their form seems to have been determined by the contour of the flat summits which they enclose. The walls vary in size, a few being upwards of 12 feet (3.7 m) high, and are so broad that they present the appearance of embankments
Levee
A levee, levée, dike , embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels...
. Weak parts of the defence are strengthened by double or triple walls, and occasionally vast lines of rampart
Defensive wall
A defensive wall is a fortification used to protect a city or settlement from potential aggressors. In ancient to modern times, they were used to enclose settlements...
s, composed of large blocks of unhewn and unvitrified stones, envelop the vitrified centre at some distance from it.
No lime
Lime (mineral)
Lime is a general term for calcium-containing inorganic materials, in which carbonates, oxides and hydroxides predominate. Strictly speaking, lime is calcium oxide or calcium hydroxide. It is also the name for a single mineral of the CaO composition, occurring very rarely...
or cement
Cement
In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
has been found in any of these structures, all of them presenting the peculiarity of being more or less consolidated by the fusion of the rocks of which they are built. This fusion, which has been caused by the application of intense heat, is not equally complete in the various forts, or even in the walls of the same fort. In some cases the stones are only partially melted and calcined; in others their adjoining edges are fused so that they are firmly cemented together; in many instances pieces of rock are enveloped in a glassy enamel-like coating which binds them into a uniform whole; and at times, though rarely, the entire length of the wall presents one solid mass of vitreous substance.
It is not clear why or how the walls were subjected to vitrification. Some antiquarian
Antiquarian
An antiquarian or antiquary is an aficionado or student of antiquities or things of the past. More specifically, the term is used for those who study history with particular attention to ancient objects of art or science, archaeological and historic sites, or historic archives and manuscripts...
s have argued that it was done to strengthen the wall, but the heating actually weakens the structure. Battle damage is also unlikely to be the cause, as the walls must have been subjected to carefully maintained fires to ensure they were hot enough for vitrification to take place.
Since John Williams, one of the earliest of British geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
s, and author of The Natural History of the Mineral Kingdom, first described these singular ruins in 1777, about fifty examples have been discovered in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. The most remarkable are:
- Dun Mac Sniachan (or DunDunDun is now used both as a generic term for a fort and also for a specific variety of Atlantic roundhouse...
Mac Uisneachan) , the largest in area at 245 m by 50 m. - BenderlochBenderlochBenderloch is a village in Argyll and Bute, Scotland.Benderloch lies on the A828 road in the coastal area of Appin, Argyll, Scotland. Its railway station closed in 1966.Benderloch forms part of the Lynn of Lorn National Scenic Area, one of 40 in Scotland....
, north of ObanObanOban Oban Oban ( is a resort town within the Argyll and Bute council area of Scotland. It has a total resident population of 8,120. Despite its small size, it is the largest town between Helensburgh and Fort William and during the tourist season the town can be crowded by up to 25,000 people. Oban...
;
- Craig Phadraig, or Phadrick, near InvernessInvernessInverness is a city in the Scottish Highlands. It is the administrative centre for the Highland council area, and is regarded as the capital of the Highlands of Scotland...
; - Ord Hill, North Kessock, near InvernessInvernessInverness is a city in the Scottish Highlands. It is the administrative centre for the Highland council area, and is regarded as the capital of the Highlands of Scotland...
; ; - Dun Deardail (or Dundbhairdghall) in Glen NevisGlen NevisGlen Nevis is a glen in Lochaber, Highland, Scotland, with Fort William at its foot. It is bordered to the south by the Mamore range, and to the north by the highest mountains in the British Isles: Ben Nevis, Càrn Mor Dearg, Aonach Mòr, and Aonach Beag...
; ; - Knock Farril (or Knockfarrel), near StrathpefferStrathpefferStrathpeffer is a village and former spa town in Ross and Cromarty, Highland, Scotland, with a population of 1,469.-Geography:It lies in a glen 5 miles west of Dingwall, with varying elevation from 200 to 400 feet above sea level...
, ; - Dun Creich, in SutherlandSutherlandSutherland is a registration county, lieutenancy area and historic administrative county of Scotland. It is now within the Highland local government area. In Gaelic the area is referred to according to its traditional areas: Dùthaich 'IcAoidh , Asainte , and Cataibh...
, ; - Finavon (or Finhaven), near AberlemnoAberlemnoAberlemno is a parish and small village in the Scottish council area of Angus. It is noted for three large carved Pictish stones dating from the 7th and 8th centuries AD ; the stones can be viewed at any time in spring-autumn, but are covered by wooden boxes in the winter to prevent frost damage...
; - Barryhill, in PerthshirePerthshirePerthshire, officially the County of Perth , is a registration county in central Scotland. It extends from Strathmore in the east, to the Pass of Drumochter in the north, Rannoch Moor and Ben Lui in the west, and Aberfoyle in the south...
; - Laws, near DundeeDundeeDundee is the fourth-largest city in Scotland and the 39th most populous settlement in the United Kingdom. It lies within the eastern central Lowlands on the north bank of the Firth of Tay, which feeds into the North Sea...
, ; - Dun Gall and Burnt IslandsBurnt IslandsThe Burnt Islands is the collective title for three small islands that lie in the Kyles of Bute off the west coast of the Scottish mainland. The islands are located at ....
, in ButeshireCounty of ButeThe County of Bute is one of the registration counties of Scotland. In 2001 its usually resident population was 13,720.-Local government county:...
; - Anwoth, (Trusty's Hill) near Gatehouse of FleetGatehouse of FleetGatehouse of Fleet is a town in Dumfries and Galloway, Scotland, which has existed since the mid-18th century, although the area has been inhabited since much earlier...
, ; - Tap o' NothTap o' NothThe Tap o' Noth is a hill fort on top of the Hill of Noth, 20 miles west of Inverurie in Aberdeenshire, Scotland at grid reference NJ485293. It is the second highest fort in Scotland and its main feature is its well-preserved vitrified wall which encloses an area of approximately 100 m by 30 m...
, AberdeenshireAberdeenshireAberdeenshire is one of the 32 unitary council areas in Scotland and a lieutenancy area.The present day Aberdeenshire council area does not include the City of Aberdeen, now a separate council area, from which its name derives. Together, the modern council area and the city formed historic...
; ; and - Cowdenknowes, in BerwickshireBerwickshireBerwickshire or the County of Berwick is a registration county, a committee area of the Scottish Borders Council, and a lieutenancy area of Scotland, on the border with England. The town after which it is named—Berwick-upon-Tweed—was lost by Scotland to England in 1482...
, .
For a long time it was supposed that these forts were peculiar to Scotland; but they are found also in County Londonderry
County Londonderry
The place name Derry is an anglicisation of the old Irish Daire meaning oak-grove or oak-wood. As with the city, its name is subject to the Derry/Londonderry name dispute, with the form Derry preferred by nationalists and Londonderry preferred by unionists...
and County Cavan
County Cavan
County Cavan is a county in Ireland. It is part of the Border Region and is also located in the province of Ulster. It is named after the town of Cavan. Cavan County Council is the local authority for the county...
, in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
; in Upper Lusatia
Lusatia
Lusatia is a historical region in Central Europe. It stretches from the Bóbr and Kwisa rivers in the east to the Elbe valley in the west, today located within the German states of Saxony and Brandenburg as well as in the Lower Silesian and Lubusz voivodeships of western Poland...
, Bohemia
Bohemia
Bohemia is a historical region in central Europe, occupying the western two-thirds of the traditional Czech Lands. It is located in the contemporary Czech Republic with its capital in Prague...
, Silesia
Silesia
Silesia is a historical region of Central Europe located mostly in Poland, with smaller parts also in the Czech Republic, and Germany.Silesia is rich in mineral and natural resources, and includes several important industrial areas. Silesia's largest city and historical capital is Wrocław...
, Saxony
Saxony
The Free State of Saxony is a landlocked state of Germany, contingent with Brandenburg, Saxony Anhalt, Thuringia, Bavaria, the Czech Republic and Poland. It is the tenth-largest German state in area, with of Germany's sixteen states....
and Thuringia
Thuringia
The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....
; in the provinces on the Rhine, especially in the neighbourhood of the Nahe
Nahe
The Nahe River is a river in Rhineland-Palatinate and Saarland, Germany, a left tributary to the Rhine. It has also given name to the wine region Nahe situated around it....
; in the Ucker Lake
Uecker
The Uecker or Ucker is a river in the northeastern German states of Brandenburg, where it is known as the Ucker, and of Mecklenburg-Vorpommern. Its source lies in the Uckermark district, near the village Alt-Temmen. It flows north through Lake Oberuckersee, Lake Mollensee and Lake Unteruckersee,...
, in Brandenburg, where the walls are formed of burnt and smelted brick
Brick
A brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar. It has been regarded as one of the longest lasting and strongest building materials used throughout history.-History:...
s; in Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
; and in several places in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, such as Châteauvieux, Péran, La Courbe, Sainte Suzanne, Puy de Gaudy and Thauron. They have not been found in England
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...
or Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
.