Searching for the secrets of St Colmac

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GEOPHYSICS will probably be a closed book to many readers of The Buteman – except perhaps those who are avid viewers of the TV series Time Team.

But two open days at Bute’s very own stone circle last weekend might just have cast some light on a branch of exploration as useful as it is fascinating.

Leading the open weekend at the stone circle at St Colmac, just off the road to Ettrick Bay, were Alistair Wilson and Dr Susan Ovenden, who spent last week on Bute surveying several sites around the island as part of a research project on early Christian sites around the so-called ‘Atlantic rim’.

The pair concluded their weekend by spending two days exploring the St Colmac site to see if they could find evidence of the precise location of a second stone circle, very near the one which is still standing today, which appeared on maps in the early 19th century and may have been blown up with gunpowder.

Alistair and Susan run their own company, Rose Geophysical Consultants, and have worked at sites the length and breadth of Britain, trying to find out as much as they can about the land beneath their feet without having to dig it up.

“Geophysics is the catch-all phrase for ‘remote sensing’, and covers a number of different techniques,” Alistair told us.

“These techniques include gradiometry, which senses minute changes in the Earth’s magnetic field and is therefore able to identify ditches, pits, middens, hearths, kilns and so on, and resistance surveying, which uses electricity passed through the ground to identify features such as stonework, foundations, paths and walls.

The couple’s initial findings from their week on Bute were presented at an open lecture at Bute Museum on Sunday evening, when Susan promised to produce a report on their conclusions once analysis is complete.

The open weekend at the St Colmac stone circle was organised jointly with the Discover Bute Landscape Partnership Scheme

Paul Duffy, the DBLPS project manager for archaeology, told us: “We want to encourage people to come and use Bute as a research lab, and we decided to use the stone circle at St Colmac because there’s a reference in an agricultural survey of Bute in 1816 which says there was a second circle very close to the existing one.

“Ultimately the Discover Bute project is about getting people out into the landscape and looking at things they might have seen hundreds of times before in a slightly different way, and if this weekend has helped achieve that it will have been something well worth doing.”