Editing Broch (section)

==Structures==
[[File:Mousa Broch 20080821 02.jpg|thumb|upright=1.2|[[Broch of Mousa]] in the Shetland Isles]]

Generally, brochs have a single entrance with bar-holes, door-checks and lintels. There are mural cells and there is a scarcement (ledge), perhaps for timber-framed lean-to dwellings lining the inner face of the wall. Also there is a spiral staircase winding upwards between the inner and outer wall and connecting the galleries.<ref>Prehistoric Scotland (R.W. Feachem, 1992) {{ISSN|0305-8980}}</ref> Brochs vary from {{convert|5|to|15|m|ft|spell=in}} in internal diameter, with {{convert|3|m|ft|adj=mid|-thick|spell=in}} walls. On average, the walls only survive to a few metres in height. There are five extant examples of towers with significantly higher walls: [[Dun Carloway]] on [[Isle of Lewis|Lewis]], [[Dun Telve]] and [[Dun Troddan]] in [[Glenelg, Scotland|Glenelg]], [[Broch of Mousa|Mousa]] in Shetland and [[Dun Dornaigil]] in Sutherland, all of whose walls exceed {{convert|6.5|m|ft}} in height.<ref>Armit (2003) p. 55.</ref>

[[File:Dun Hallin - geograph.org.uk - 414645.jpg|left|thumb|The remains of [[Dun Hallin]] Broch, [[Isle of Skye|Skye]]]]

Mousa's walls are the best preserved and are still {{convert|13|m|ft}} tall; it is not clear how many brochs originally stood so high. A frequent characteristic is that the walls are galleried: with an open space between, the outer and inner wall skins are separate but tied together with linking stone slabs; these linking slabs may in some cases have served as steps to higher floors. It is normal for there to be a cell breaking off from the passage beside the door; this is known as the guard cell. It has been found in some Shetland brochs that guard cells in entrance passageways are close to large door-check stones. Although there was much argument in the past, it is now generally accepted among some archaeologists that brochs were roofed, perhaps with a conical timber framed roof covered with a locally sourced thatch. The evidence for this assertion is still very scanty, although excavations at Dun Bharabhat, Lewis, may support it. The main difficulty with the interpretation continues to be identifying potential sources of structural timber, though bog and driftwood may have been sources.{{citation needed|date=August 2017}}

Very few of the brochs on the islands of [[Orkney]] and [[Shetland]] have cells on the [[ground-floor|ground floor]]. Most brochs have scarcements (ledges) which may have allowed the construction of a wooden first floor (spotted by the antiquary George Low in [[Shetland]] in 1774), and excavations at Loch na Berie on the Isle of Lewis may show signs of a further, second floor (e.g. stairs on the first floor, which head upwards). Some brochs such as Dun Dornaigil and [[Culswick]] in Shetland have unusual triangular lintels above the entrance door.<ref>{{Cite web |title=Iron Age and Later Prehistory - Dun Dornaigil |author=Steveco |work=The Megalithic Portal |date=11 November 2002 |url= https://www.megalithic.co.uk/article.php?sid=1252119992|url-status=live|archive-url=https://web.archive.org/web/20110610083053/http://www.megalithic.co.uk/article.php?sid=1252119992|archive-date=10 June 2011}}</ref><ref>{{Cite web|url=http://www.rockstanza.info/node/11|url-status=usurped|title=Brochs of Shetland –- Culswick|date=23 October 2006|first=Chris|last=McGinlay|archive-url=https://web.archive.org/web/20080513010427/http://www.rockstanza.info/node/11|archive-date=13 May 2008}}</ref>

[[File:Scotland Glenelg broch.jpg|thumb|upright=1.2|[[Dun Telve]] Broch, [[Glenelg, Highland|Glenelg]]]]

As in the case of [[Old Scatness]] in Shetland (near [[Jarlshof]]) and [[Burroughston Broch|Burroughston]] on [[Shapinsay]], brochs were sometimes located close to [[arable land]] and a [[water supply|source of water]] (some have wells or natural springs rising within their central space).<ref>Hogan, C. Michael (7 October 2007) [http://www.megalithic.co.uk/article.php?sid=7891 ''Burroughston Broch''] {{webarchive|url=https://web.archive.org/web/20110610071233/http://www.megalithic.co.uk/article.php?sid=7891 |date=10 June 2011 }} The Megalithic Portal; retrieved 11 May 2008.</ref> Sometimes, on the other hand, they were sited in wilderness areas (e.g. [[Levenwick]] and [[Culswick]] in Shetland, Castle Cole in Sutherland). Brochs are often built beside the sea ([[Carn Liath (broch)|Carn Liath]], Sutherland); sometimes they are on islands in [[lochs]] (e.g. [[Clickimin]] in Shetland).<ref>{{Cite web |title=Lerwick, South Road, Clickimin - Blockhouse (Iron Age), Broch (Iron Age), Enclosure (Iron Age), Fort (Prehistoric), Settlement (Prehistoric) |author= |website=Canmore - National Record of Historic Environment |date=2018<!--date of latest reference on page--> |url= https://canmore.org.uk/site/1049/lerwick-south-road-clickimin}}</ref>

About 20 Orcadian broch sites include small settlements of stone buildings surrounding the main tower. Examples include Howe, near [[Stromness]], [[Gurness Broch]] in the north west of [[Mainland, Orkney]], Midhowe on [[Rousay]] and Lingro near [[Kirkwall]] (destroyed by a farmer in the 1980s). There are "broch village" sites in Caithness, but elsewhere they are unknown.<ref>Armit (2003) pp. 95-106.</ref>

Most brochs are unexcavated.<ref>Armit (2003) p. 51 notes that of 140 Atlantic roundhouses in the [[Outer Hebrides]] only 14 have been "at least partially excavated".</ref> The end of the broch building period seems to have come around AD 100–200.<ref>{{Cite book|title=The Macmillan Encyclopedia|publisher=Market House Books, Ltd.|year=2003|edition=2nd|via=Credo Reference}}</ref><ref>{{Cite web|url=https://www.academia.edu/10772443|title=The Broch Cultures of Atlantic Scotland. Part 2. The Middle Iron Age: High Noon and Decline c. 200 BC–AD 550|last=Mackie|first=Euan W.|year=2010|website=Academia.edu|access-date=15 May 2019}}</ref> Those that have been properly examined show that they continued to be in use for many centuries, with the interiors often modified and changed, and that they underwent many phases of habitation and abandonment.