The range of recurring ground-plans of timber roundhouses in much of southern and eastern Scotland are often known by short-hand reference to their salient structural feature as of ring-groove, post-ring and ring-ditch construction . The broad distinctions have merit, but the structural features are not exclusive: buildings with a ring-groove wall regularly have an internal post-ring providing the main structural support, while ring-ditch houses always have a post-ring and sometimes have a ring-groove wall; post-rings alone may have had a turf wall, but could also have lost any ring groove to erosion.
It is unclear what these distinctions signify, particularly as in many areas they are in use over the same long timespan and, indeed, are not uncommonly found as elements of the same settlement. An attempt was made to model possible ethnic, functional or social variations for the post-ring houses and ring-ditch houses juxtaposed at Kintore, Aberdeenshire. Here the excavators argued for the occupants of ring-ditch houses having a dominant relationship with their post-ring counterparts (Cook & Dunbar 2008) an argument that has not found general agreement.
Tofts Ness roundhouse, Orkney © Dockrill
The idea of houses as cultural and chronological markers in the Tyne-Forth area proposed by Hill (1982b) has been applied in Eastern Dumfriesshire to ring-ditch houses (RCAHMS 1997, 161-2). It does not, however, seem to be applicable for other areas - e.g. the North-East (Cook & Dunbar 2008; Dunwell & Ralston 2008). For most Atlantic areas (with the possible exception of East Lothian) the chronological control is currently inadequate to support the use of house plans as type-fossils, and indeed the evidence generally contradicts such simple views.
Stone-built 'hut circles' occur extensively across Scotland, in 'upland' contexts on the mainland and on the inner isles in Bronze Age and Iron Age contexts, though not in parts of the south-east, or on the Northern Isles or Outer Hebrides. They occur in both Bronze Age and Iron Age contexts. Excavation suggests that the majority belong to the second millennium BC, with a smaller proportion indicating activity in the first millennium BC (Halliday 1999, 56-8).
The most dramatic stone-built roundhouses are those traditionally called brochs, and typical of Atlantic Scotland. The dramatic broch towers such as Mousa are now normally seen as a development from earlier, less complex but still massive stone roundhouses, the details of which remain a matter of considerable debate. The terminology of simple and complex Atlantic roundhouses was developed to encompass this architectural variety (including sites otherwise termed brochs and duns) while emphasising that these were variants of the roundhouse tradition; this is discussed and referenced more fully below (see theme 5.9).
Coring on the Iron Age islet site of An Dunan, Uig, Western Isles © Uig Landscape Project
While there is a great preponderance of round or oval buildings, there is, however, also a much smaller range of other structures present, of unrelated forms, that are generally ascribed a non-domestic function (i.e souterrains, 'four-posters' and a miscellany of odd structures like that at An Dunan, Uig, Western Isles (Gilmour 2002); some are considered further below (see theme 5.10).
Crannogs (artificial islets) are distributed across Scotland where conditions are suitable, with Late Bronze Age/Early Iron Age dates for the earliest recognisable timber crannogs and artificial islets constructed on a large scale during the period c. 800-500 BC, which has been termed the 'crannog event horizon' by Cavers (2006). Regional distinctions have been proposed by Henderson (1998), based upon visible characteristics, although the value of this classification has been questioned by Harding (2000), particularly in terms of the relationship with island duns. Crone (2000, 4) understands these regional differences principally in terms of the availability of raw resources rather than as cultural differences. She notes that currently known distributions may reflect research bias (Crone 2000, 2), except for the situation in the south-east of Scotland where there appears to be a genuine dearth of crannogs, probably largely due to the relative scarcity in this region of suitable locations.
There is no reason to assume all crannogs were domestic residences or even supported a single circular house (Harding 2000). 'Crannog' has been argued as a portmanteau term (Harding 2000) for a type of site that included domestic occupation, but the excavated sample is insufficient to say whether or not crannogs performed a range of functions, whether permanent, periodic or seasonal. Marine crannogs (a disparate group found mostly in the Firth of Clyde and Beauly Firth) probably were not primarily domestic residences, instead serving a range of functions for craft-processing and utilising the sea's resources (Hale 2000). Certainly Irish investigation of crannog sites, which has been more intensive than in Scotland, suggests that these sites vary widely in function, over a very widely varying chronology, with industrial, ceremonial / funerary and settlement functions being identified (Fredengren 2002).
- There is a continuing need for the definition of local types and sequences (see also theme 3.3).
- Is variation in house size and construction simply a product of the availability of resources (Cook & Dunbar 2008 , 13), or were other social factors responsible? Can clearer patterns in space and time be discerned?
- What range of activities took place on crannogs?