Na Clachan Aoraidh Geophysical Survey

Date 24 October 2016 - 11 November 2016

Event ID 1025230

Category Project

Type Project

Permalink http://canmore.org.uk/event/1025230

NN 83861 62018 (NN86SW 3) The site is referred to as Na Carraigean Edintian or Na Clachan Aoraidh ‘the stones of worship’ (Burl 1988, 187). The standing stones comprise four boulders of quartziferous schist forming a quadrilateral c3.2 x 3.6m; the stones are graded with the tallest occurring in the SW corner and these are set on the circumference of a

circle which is c4.3m in diameter, although all but one of the stones are now leaning. The stones are set on a low mound or platform formed from cairn material and which is c16.5 x 8.85m in diameter. The platform appears to be kerbed by smaller stones. There is a slight hollow in the centre of the mound, thought to be the result of undocumented activities of earlier antiquarians. In recent years a bonfire within the hollow may have caused further damage to the monument.

The site was subject to topographical and a geophysical survey, including magnetometry and resistivity (Archaeological Services Durham University) and laser scanning (AOC Archaeology), the results of which were used to produce a 3D visualization of all elements of the site. A stone kerb or revetment was detected encircling the standing stones and outside of which was an arc of low resistance consistent with a ditch; this feature appears to resemble the ditch which encircled the natural mound of the four-poster at Lundin Farm South-East (Stewart 1967). Within the platform

two negative magnetic anomalies were interpreted as voids, possible caused by cists or stoneholes. Within the slightly sunken centre was a positive magnetic anomaly which could be detecting the backfill of an antiquarian excavation. On the S side of the platform another curvilinear positive magnetic anomaly was thought to be the fill of another ditch and

which may well be the remains of a ring ditch. Also on the S side of the platform a possible stone wall/dyke was detected and an equally stony rectangular feature was recorded on the E side of the four-poster platform.

A sample excavation was undertaken, 24 October – 11 November 2016, in order to:

• Evaluate the damage upon the archaeological deposits caused by an illegal fire pit

• Ascertain the extent and nature of surviving archaeological deposits

• Ensure the continued protection of surviving features

• Enhance the historic environmental record

The excavation of three trenches over and adjacent to the monument revealed:

• The four standing stones occurred within and at least one was contemporary with the stone platform which was roughly 0.50m thick.

• The platform was edged by a kerb of larger cobbles.

• There was no ditch outside the kerb.

• One of the internal magnetic anomalies was shown to be a void within the stone platform, no archaeological material was observed within this; it is unclear whether this is an empty cist or a fortuitous void.

• The central hollow was not caused by antiquarian digging but it was the location of a probable tree throw that had been modified and into which a central pit containing cremated bone (human?) and ashes had been dug.

• There was no ring ditch on the S side of the monument.

• There was no stone wall or dyke on the S side of the monument.

• There was no stony rectangular feature on the E side of the monument.

• There was no entrance into the monument.

• The heat effects of the central bonfire had not penetrated below the turf and had not caused any damage to the archaeological horizons.

In conclusion, the four poster stone circle is a simply constructed monument comprising an oval stone platform cairn and four stone orthostats arranged around a central pit which contains burnt bone mixed with ash and redeposited soil. The monument appears to have been centred on a hollow which was created by a collapsed or dead tree. The

site was backfilled and a layer of gravel placed upon terram but under the turf in the centre of the monument to protect the underlying deposits from damage in the event of further illegal bonfires.

Archive: HES and NRHE (intended)

Funder: Forestry Commission Scotland

Clare Ellis – Argyll Archaeology

(Source: DES, Volume 17)