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Geophysical Survey

Date 30 July 2011 - 31 July 2011

Event ID 963274

Category Recording

Type Geophysical Survey


The St Colmac stone circle consists of an extant stone circle that measures c13m diameter internally. Work on 18th-century cartographic records and archive research by George Geddes of RCAHMS had suggested a second stone circle was located c25m to the W, prior to its removal by blasting powder in the early 19th century. There is little visible evidence of the second stone circle. A geophysical survey was undertaken 30–31 July 2011 at the request of the DBLPS to further investigate the site.

Whilst there is some confusion in the results arising from the natural geology and shallow bedrock the ‘lost’ stone circle is apparent in the data. It is roughly circular in plan, c22m in diameter and located c40m NW of the extant stone circle. It is possible to identify six potential stone sockets, with the data suggesting that at least two may contain remnants of standing stones, though the survey resolution does not make this identification absolute.

Perhaps as important, but more surprising, is the detection of two sub-circular concentric, but offset, ditches with a central rectangular structure. The structure (c11 x 8m) is orientated roughly N–S but presents no anthropogenic signature in the gradiometer data, as might be expected from a dwelling. It is possible that this is the site of a Christian chapel. Whilst this site is close to the known chapel site of East St Colmac c300m to the N, its location close to a stone circle does support its interpretation as a potential chapel site.

Archive: Rose Geophysical Consultants

Funder: Discover Bute Landscape Partnership

Rose Geophysical Consultants 2011

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