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Dun Mor a' Chaolais, broch and cup-marked rock, Millton, Tiree

A Scheduled Monument in Oban South and the Isles, Argyll and Bute

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Latitude: 56.5303 / 56°31'49"N

Longitude: -6.7455 / 6°44'43"W

OS Eastings: 108322

OS Northings: 747678

OS Grid: NM083476

Mapcode National: GBR 9CQG.C2Q

Mapcode Global: WGX9Z.C433

Entry Name: Dun Mor a' Chaolais, broch and cup-marked rock, Millton, Tiree

Scheduled Date: 19 November 1997

Source: Historic Environment Scotland

Source ID: SM6906

Schedule Class: Cultural

Category: Prehistoric domestic and defensive: broch; Prehistoric ritual and funerary: cupmarks or cup-and-ring

Location: Tiree

County: Argyll and Bute

Electoral Ward: Oban South and the Isles

Traditional County: Argyllshire


The monument consists of a broch and its outwork, the former exhibiting at least two phases of construction, which occupy the summit of a low rocky hill, together with a rock displaying cup markings. The broch stands on the summit of Dun Mor a'Chaolais, a low rocky hill dominating the NE end of Tiree.

The hill is not steep and provides only limited natural protection. A number of later structures have been constructed over the site of the broch and its outworks, and modern field boundaries cross the site.

The broch measures approximately 12m in internal diameter, with a wall originally about 3.7m thick. However, the wall has been widened to approximately 5.8m in thickness by the subsequent addition of an external revetment on all sides. Such a widening of the wall can be parallelled in two brochs on Mull. Part of the facework from each phase of work can be distinguished, and the character of the build differs considerably.

Both phases of work are of dry-stone construction. The stone has been heavily robbed, probably for the construction of the field walls which cross the site. The broch entrance passage can be recognised on the NW, as can part of an intramural gallery about 0.8m wide within the SW quadrant of the broch, and a small mural chamber (together with traces of a possible second one) within the SE quadrant.

The ruined foundations of a later rectangular building immediately to the SW of the entrance passage may cover another such chamber. The SW part of the broch is relatively well preserved, up to 1.5m high, although the NE part has been more intensively cultivated and is more denuded.

The broch is surrounded by an outwork which may curve inward to meet the outer face of the main structure on the W. It was entered from the S, but another entrance may have existed to the N. It is preserved up to 1.6m in height although, like the broch, the SW half is better preserved than the NE. The outwork is approximately oval on plan, and measures over 50m N-S. It extends up to 18m from the outer face of the broch.

Approximately 27m W of the broch, on the edge of a rock outcrop, is a group of at least 7 cup markings, the largest about 80mm in diameter.

The area to be scheduled is a circle 100m in diameter, centred on the broch, as defined in red on the enclosed map, and it includes the broch and its outwork, the cup-marked rock and the later structures. The scheduling excludes the above-ground structures of both the OS triangulation station and of modern fences.

Source: Historic Environment Scotland

Statement of Scheduling

The monument is of national importance because the broch is a well-preserved field monument which exhibits a range of architectural details. It has the potential to provide information about later prehistoric architecture and the nature, organisation and development of Iron Age society.

The associated cup-markings indicate that the rocky hill on which the broch is situated was also the site of earlier prehistoric activity: such carvings are rare in the Argyll islands, although they are likely to relate to the internationally significant examples on the Argyll mainland.

Source: Historic Environment Scotland



RCAHMS records the monument as NM 04 NE 1.


RCAHMS, Inventory of Monuments in Argyll, Vol. 3, 91-2 (Entry 166).

Source: Historic Environment Scotland

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