The Society funded geophysical survey at two Pictish symbol stones
Gordon Noble, Meggen Gondek and Oskar Sveinbjarnarson
In 2011-12 exciting results were obtained from evaluative excavations conducted in relation to the Craw Stane, Rhynie. The excavations demonstrated that the Craw Stane stood at the entrance to an elaborate 6th century fort defined by a plank-built palisade, earthwork enclosures, all enclosing a series of timber buildings built by plank and post techniques. Exceptional finds were also identified including 6th century Late Roman Amphora (B-ware), glass from Merovingian France, metalworking moulds, iron and copper alloy pins and metalwork and crucible fragments. As part of a wider programme to evaluate other symbol stone monuments in Northeast Scotland the Society of Antiquaries of Scotland funded a programme of geophysical survey at two other symbol stone locations in Aberdeenshire. The two sites were the Picardy Stone and Tillytarmont.
Tillytarmont is the findspot of Five Pictish Class I symbol stones found during ploughing from 1867-1974. The last to be found, Tillytarmont 5 was found above a stone spread adjacent to a square ‘cairn’ excavated (but unpublished) by Woodham in 1975 (NJ54NW 24) (Woodham 1975). The findspots of the stones is on the haughland at the confluence of the Isla and Deveron rivers.
During late September and early October 2012 both sites were surveyed with the aim of identifing any archaeological features in association with the location of the stones as part of a wider project to contextualise Class I Pictish stones.
Both surveys were conducted with a Bartington Grad 601-2 fluxgate gradiometer. The machine is capable of measuring magnetic variations to 0.01nT (nanoTesla) and carries two probes, spaced 1m apart horizontally, which enable survey of two transects lines at the same time. The transect lines were spaced out and walked at 1 metre interval and 8 samples were measured every meter along the transect lines. After the survey the location of the survey grid was measured with a Topcon DGPS with horizontal accuracy of 0.8cm.
The geophysical survey around the Picardy symbol stone reveals that there are number of potential features which may be significant to the understanding of the function of the site and the stone. The antiquarian discovery of a cairn and possible burial adjacent to the symbol stone indicates the potential for burial features to be found in this field. The geophysical results include linear and square anomalies that could represent elements of contemporary activity, perhaps even burial mounds and square barrows. However, the results of the survey are hampered by the geology of the field and a number of these anomalies may be geological in nature. Only ground-testing of the anomalies will be able to verify and test the results of the survey.
Given Woodham’s (1975) reports of stone spreads and a square cairn the results of the survey at Tillytarmont were disappointing, but interesting nonetheless. The only definite features visible on the geophysical survey are linear E-W routeways (marked P7) which mark an old routeway across the Isla and the Deveron linking two fords. It would appear that the symbol stone distribution at Tillytarmont relates, at least in part, to this ancient routeway across the landscape. Test trenching carried out after the survey shows that many of the other anomalies were either geological or modern in nature. The cairn or stone spreads reported by Woodham were not idenitified – either these have been entirely removed by modern ploughing or they lie elsewhere on the haughland. Unfortunately, to date, only very basic records of his excavations have been uncovered. The anomlies P3-5 are striking, but test pits in these areas failed to identify archaeological features – these may simply be geological features or traces of activity that now only survives in the ploughsoil.
Larger-scale stripping of topsoil on the haughland would be a fruitful objective for future work to test the survival of the features identified by Woodham and to further investigate the context of the stones and features identified on the survey.
Overall the results of the survey programme shows promise in a geophysical approach to Pictish Class I symbol stones that can be extended to other monuments and landscapes across Pictland and beyond. The best results, however, will only be obtained where geophysical survey can be followed up by excavation, ideally large-scale stripping of topsoil to test anomalies. The landscape context of these monuments is key to understanding these monuments and it is only through more intensive programmes of research that important issues surrounding context, siting and function will be revealed.
Stuart, J. 1856. Sculptured stones of Scotland, vol.1 Aberdeen.
Woodham, A A (1975) ‘Tillytarmont cairn’, Discovery & Excavation Scotland 1975, 6.
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