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Sean Dun, dun 180m SSE of Balygrundle No. 1

A Scheduled Monument in Oban North and Lorn, Argyll and Bute

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Latitude: 56.5021 / 56°30'7"N

Longitude: -5.5034 / 5°30'12"W

OS Eastings: 184484

OS Northings: 739945

OS Grid: NM844399

Mapcode National: GBR DCSJ.PWJ

Mapcode Global: WH0FZ.FTKT

Entry Name: Sean Dun, dun 180m SSE of Balygrundle No. 1

Scheduled Date: 23 July 1956

Last Amended: 15 March 2013

Source: Historic Environment Scotland

Source ID: SM245

Schedule Class: Cultural

Category: Prehistoric domestic and defensive: dun

Location: Lismore and Appin

County: Argyll and Bute

Electoral Ward: Oban North and Lorn

Traditional County: Argyllshire


A group of three detached military aircraft sheds (hangars) built in 1913-14 for the Royal Flying Corps, as part of the former Montrose Air Station. Rectangular on plan and arranged from north to south, in an eastward-facing crescent shape, the sheds are symmetrical with pitched roofs and gabled north and south elevations. Constructed from timber-frames over a base of concrete and brick, they are clad in corrugated metal. The east elevation of each shed has a pair of gables, each of which has four timber-panelled sliding access doors. The cladding of Nos. 46 and 47 is concealed by late-20th century secondary steel cladding and the access doors of these two sheds have been altered and reduced in size. There is a single-storey timber-clad lean-to abutting the south elevation of the southern shed (No.48), which was added later and is excluded from the listing.

The interior of No.48 was seen in 2017. It is open plan and subdivided in two by a red brick wall, which is likely to be a later addition, as comparable examples such as Farnborough do not appear to include this. The finishes are plain with a smooth concrete floor, painted and rendered walls and later ceiling tiles. The exposed triangular timber roof trusses have diagonal cross-bracing, vertical iron tension rods and diagonal webbing. Low-level late-20th century partitions have been added to the south elevation of No.48 (of no interest in listing terms).

In accordance with Section 1 (4A) of the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 the following are excluded from the listing: The timber extension on the south of Building 48.

Source: Historic Environment Scotland

Statement of Scheduling

Cultural Significance

The monument's cultural significance can be expressed as follows:

Intrinsic characteristics

The dun occupies a site of great natural strength, on the summit of a knoll surrounded on the E, S and N sides by near vertical cliffs and a steep-sided gully. The footprint of the dun broadly covers the elongated summit, with only a small area to the N falling outside its circuit. The dun itself survives as the remains of a roughly circular wall-circuit, with an overall diameter of around 25m. The wall now appears as a stony bank spread to 5.5m wide on average, but some of the inner and outer facing stones have been recorded previously, leading researchers to suggest that the original wall-thickness was about 4.1m. The approach to the dun was from the W where a gentle slope offers relatively easy access. Within the entrance to the WSW, part of the passage-wall and an inner corner-stone were visible in 1968. Outside the entrance to the W and S, a concentric earthwork arc forms an outwork to the dun. A break in the W side of this feature is slightly offset from the dun entrance, but represents the likely access route through the outwork to the dun. The interior ground surface of the dun is uneven and is likely to contain structural remains and archaeological evidence of occupation. The enclosure to the W is situated on a level shelf immediately below the dun, but is probably later than the dun as it almost blocks the entrance through the outwork. At least two of the clearance cairns appear to overlie the enclosure and are likely to be later than both the dun and the enclosure. This evidence for a development sequence between the dun, outwork and enclosure adds to the archaeological significance and potential of the site.

Overall, the footprint of the monument is intact and it survives in reasonably good condition. Despite the relatively slight appearance of the perimeter wall today, there is high potential for the survival of buried deposits and features beneath and beyond the wall, within the dun interior, and within the outwork and enclosure. Future examination of the dun could provide detailed information about its date, form and construction, and the wider development sequence of the dun and its outwork and the enclosure. Investigation of the interior of the dun could contribute to our understanding of how it was used and how this may have changed over time. Buried artefacts and palaeoenvironmental evidence can contribute to our understanding of how people lived and worked, the extent and nature of trade and exchange, and the nature of the agricultural economy. The monument has the potential to contribute to our understanding of the nature of Iron Age settlement and the design and development of these small defended enclosures.

Contextual characteristics

This type of relatively small, defended settlement characterises much of the coastal occupation of Argyll and Atlantic Scotland in later prehistory. There are eight known duns on Lismore and almost 50 in the Lorn area. They belong to a much broader category of later prehistoric settlement, which includes brochs, forts, crannogs, duns and hut circles. Altogether, over 500 later prehistoric settlements are known in Argyll. It is believed that duns represent the remains of the living spaces of small groups or single families. They are largely a coastal phenomenon and tend to be located on locally high ground, along prominent coastal routes or within easy reach of the coast, as in this case.

The duns of Lismore are all sited on rock outcrops and take advantage of the natural prominence and defence they afford. Sean Dun has a seaward outlook and would have been clearly visible from the sea, which, combined with its prominent knoll-top position, suggest that defence and visibility were the chief factors that determined its siting here (rather than proximity to agricultural land, for instance). A series of duns and forts lines this coastline, while Dun Mor lies some 700m W and inland of Sean Dun. The relationship between the duns in the island merits further research, but it is likely that they formed part of a network of similar sites along the Lismore coast. Sean Dun is probably also broadly contemporary with the substantial broch at Tirefour and the possible broch at Loch Fiart. Sean Dun has high potential to contribute to our understanding of the Iron Age occupation of Lismore and further afield.

Associative characteristics

The site is labelled as 'Fort (Sean Dùn)' on the first edition Ordnance Survey map.

National Importance

This monument is of national importance because it has an inherent potential to make a significant addition to our understanding of the past, in particular, the design and construction of later prehistoric, small defended settlements in western Scotland, and their place in the wider economy and society. There is good potential for well-preserved archaeological remains surviving within and immediately outside the dun and its outwork. These buried remains can tell us much about the people who built and lived in the settlement and the connections they had with other groups. The loss of the monument would significantly diminish our future ability to appreciate and understand the occupation of Argyll in the later prehistoric and early historic periods.

Source: Historic Environment Scotland



Canmore: CANMORE ID: 276376, 252022, 252023


Ordnance Survey (surveyed 1923, published 1924) Forfarshire XXVIII.14 (Dun; Montrose). 25 inches to the mile. 2nd and later Editions. Southampton: Ordnance Survey.

Ordnance Survey (published 1957) NO65 & Parts of NO75 (includes: Montrose). 1:25,000. Southampton: Ordnance Survey.

Map of Montrose Training Depot Station (c.1918) in Fife, M. (2007) Scottish Aerodromes of the First World War, Stroud: Tempus Publishing Limited, p.113.

Printed Sources

Barclay, G. (2014) The Built Heritage of the First World War in Scotland, Edinburgh: Historic Scotland and RCAHMS, pp.7-11

Brown, I. Burridge, D. Clarke, D. Guy, J. Hellis, J. Lowry, B. Ruckley, N. and Thomas, R. (1995) 20th Century Defences in Britain, An Introductory Guide; Handbook of The Defence of Britain Project, York: Council for British Archaeology, p.104.

Fife, M. (2007) Scottish Aerodromes of the First World War, Stroud: Tempus Publishing Limited, p. 7, 10, 18, 21, 97, 112-114, 117, 119, 121, 177, 178, 180, 183, 221.

Francis, P. (1996) British Military Airfield Architecture – From Airships to the Jet Age, Somerset: Patrick Stephens Limited, pp.9-15, 81-110.

Smith, D. (1983) Action Stations: 7. Military airfields of Scotland, the North-East and Northern Ireland, Cambridge: Patrick Stephens Limited, pp.152-156.

Online Sources

War in the Air, WW100 Scotland, p.8 [accessed 20/03/2018]

RAF Montrose Air Station Heritage Centre [accessed 14/03/2018]

Canmore, Montrose Airfield, Building 46 [accessed 14/03/2018]

Canmore, Montrose Airfield, Building 47 [accessed 14/03/2018]

Canmore, Montrose Airfield, Building 48 [accessed 14/03/2018]

Canmore, Montrose Airfield, General [accessed 14/03/2018]

Commonwealth War Graves Commission, Montrose (Rosehill) Cemetery

Commonwealth War Graves Commission, Montrose (Sleepyhillock) Cemetery

Ronald V, (2010-13) Abandoned & Little-Known Airfields: United Kingdom, Scotland: Tayside [accessed 14/03/2018]

Historic England, First World War: Airfields [accessed 14/03/2018]

Historic England, Catterick [accessed 20/07/2018]

Historic England, Farnborough [accessed 20/07/2018]

Historic England, Eastchurch [accessed 14/03/2018]

Historic England, Historic Military Aviation Sites, Conservation Guidance [accessed 14/03/2018]

Historic England, Larkhill [accessed 14/03/2018]

The Aerodrome, No.2 Squadron [accessed 14/03/2018]

SCRAN, Cross-section of 1913 Aircraft Hangar at Montrose Airfield, Tayside [accessed 14/03/2018]

Other Information

Montrose Heritage Centre

Listed Building Record (1988)


Source: Historic Environment Scotland

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