- Vitrified fort
Vitrified fort is the name given to certain crude stone enclosures whose walls have been subjected in a greater or less degree to the action of fire [cite web |url=http://www.brigantesnation.com/VitrifiedForts/VitrifieedForts.htm |title=Vitrification of Hill Forts |accessdate=2008-01-24 |language=English] . 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 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 ramparts, 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 the walls were subjected to vitrification. Some antiquarians 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. Currently, the most popular suggestion is that the process was a symbolic demonstration of power, spectacularly removing the seats of a warrior aristocracy.
Since
John Williams , one of the earliest of Britishgeologist s, and author of "The Natural History of the Mineral Kingdom", first described these singular ruins in1777 , about fifty examples have been discovered inScotland . The most remarkable are:
* Dun Mac Sniachan (Dun Mac Uisneachain or Dun Macsnoichan), the ancient Beregoiium,Benderloch , north ofOban , oscoor|NM902381|map location;
* Craig Phadraig, or Phadrick, nearInverness ; oscoor|NH640452|map location
* Ord Hill, Kessock, nearInverness
* Dun Dhardhail (Dunjardil) inGlen Nevis ;
* Knockfarrel (or Knockfarrail), nearStrathpeffer , oscoor|NH505585|map location;
* Dun Creich, inSutherland , oscoor|NH651882|map location;
* Finavon (or Finhaven), nearAberlemno oscoor|NO507556|map location;
* Barryhill, inPerthshire ;
* Laws, nearDundee , oscoor|NO490349|map location;
* Dun Gall andBurnt Islands , in Buteshire;
* Anwoth, nearGatehouse of Fleet , oscoor|NX589560|map location;
*Tap o' Noth ,Aberdeenshire ; and
* Cowdenknowes, inBerwickshire , oscoor|NT585370|map location.Dun Mac Tjisneachain is the largest in area, being 250 yd. long by 50 yd. broad.
For a long time it was supposed that these forts were peculiar to Scotland; but they are found also in
County Londonderry andCounty Cavan , inIreland ; in Upper Lusatia,Bohemia ,Silesia ,Saxony andThuringia ; in the provinces on theRhine , especially in the neighbourhood of theNahe ; in the Ucker Lake, in Brandenburg, where the walls are formed of burnt and smeltedbrick s; inHungary ; and in several places inFrance , such as Châteauvieux, Péran, La Courbe, Sainte Suzanne, Puy de Gaudy and Thauron. They have not been found inEngland orWales .References
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