Swartigill Burn

In January 2007, CFA Archaeology Ltd carried out a programme of palaeoenvionmental survey on behalf of the Scottish Wetlands Archaeology Programme (SWAP) within the locality of Loch of Yarrows, Caithness. This project is one of several research studies carried out by SWAP during 2006 as part of a wider framework to promote Scottish Wetland Archaeology (SWAP 2007 forthcoming) . The survey was carried with the help of volunteer members of the Caithness Archaeological Trust (CAT) and the Loch of Yarrows Archaeological Trust (YAT).

The project was designed to test the viability of Ground Penetrating Radar (GPR) over variable depths of blanket or mire peat formations. Three study areas were selected and included a sequence of deep, intermediate and shallow peat. The project was carried out following above average winter rainfalls that resulted in high saturation of the blanket peat which covers much of the area surrounding the study areas. A series of grids were peat probed and cored providing a biostratigraphic and basal profile of each survey grid. Each grid was subjected to GPR survey.

The three sites selected for survey were as follows:

Oliclate Farm to the north of Loch of Yarrows (grids A and B)

South of Loch of Yarrows (Yarrows 1 and 2)

Swartigill Burn, to the north of Loch of Yarrows

The results confirm that at Oliclate Farm, there is good correlation with the basal profile and biostratigraphic profiles obtained fom coring, although slight attenuation (loss of the radar signal) did occur owing to the very saturated nature of the peat. There is good correlation within the biostratigraphic profile and those obtained to the east by Tipping et al (2005). At South Yarrows 1, the shallow peat area, again good correlation was recorded between the environmental record and GPR results. At South Yarrows 2, an infilled palaeochannel provided the best correlation between the environmental record and the GPR results. At Swartigill Burn, the site of possible building remains resting on alluvial clay, the radar returns were confused by the distribution of building stone, possibly demolition material that was spread across the site. Although no wall alignments could be defined from within the radar patterns, the extent of the site within the survey grid itself is visible.

The results of this pilot study confirm that severely saturated peat does not adversely effect the radar returns gained from the apparatus used and both peat stratigraphy and basal morphology can be measured. GPR survey can provide a cost effective, non-destructive method for site demarcation of archaeological sites and monuments buried below deep peat.

ND 32110 45730 A fluxgate gradiometer survey, an earth resistance survey and a ground penetrating radar survey were carried out, 1–2 August 2014, on land next to the Burn of Swartigill. The survey aimed to characterise the extent and the nature of a known Iron Age site being eroded by the burn. The gradiometer survey has highlighted a 25 x 30m area, presenting strong magnetic variation likely to be associated with anthropogenic activity, and potentially indicative of the presence of a settlement. The earth resistance survey results suggested, within this area of enhancement, the presence of a potential sub-rectangular structure measuring 10 x 16m. The ground penetrating radar helped clarify the nature of some anomalies visible in the gradiometer and earth resistance survey. It is possible that the results of this geophysical survey

may have revealed a late Iron Age settlement, with a ‘wag’ or ‘figure-eight’ building.

Archive: ORCA

Funder: Yarrows Heritage Trust

Nick Card, Rosalind Aitken and Thomas Desalle – ORCA

(Source: DES)

ND 32110 45730 Ground penetrating radar survey.

Archive: ORCA

Funder: Yarrows Heritage Trust

Nick Card, Rosalind Aitken and Thomas Desalle – ORCA

(Source: DES)

ND 32110 45730 Resistivity survey.

Archive: ORCA

Funder: Yarrows Heritage Trust

Nick Card, Rosalind Aitken and Thomas Desalle – ORCA

(Source: DES)

ND 32110 45730 Magnetometry survey.

Archive: ORCA

Funder: Yarrows Heritage Trust

Nick Card, Rosalind Aitken and Thomas Desalle – ORCA

(Source: DES)

ND 3210 4573 A fairly small-scale exploratory excavation took place at the Burn of Swartigill, 16–20 September 2015. The work was undertaken in collaboration with the Yarrows Heritage Trust and with good attendance from volunteers from the local community.

The aims were modest and linked to scoping out the site for a potential, more expansive, future piece of work. One of the project objectives was to ‘ground-truth’ a geophysical survey undertaken in an earlier episode of work by ORCA. This survey had potentially pointed to the presence of a substantial rectangular building form, perhaps a post-broch Iron Age period ‘Wag’ a form of building well known in Caithness and Sutherland.

A second aim was to try to establish something of the character of archaeological remains that had been discovered eroding out from the side of the Burn of Swartigill and recorded and reported in 2012 by Yarows Heritage Trust. These remains had included probable masonry and an interesting, possibly two-phased, assemblage of Iron Age ceramics.

A small excavation trench (c3.5 x 3.0m) was placed to incorporate part of the erosion front, a more extensive area behind and a long narrow extension c3m running southwards. While a series of small trial trenches (1 x 1m, 1 x 1m and 2 x 1m respectively) were opened to give keyhole views into some of the other geophysical anomalies picked up in the survey. Substantial alluvial deposits from the floodplain of the burn were found to shroud archaeological remains to the S of the burn frontage itself, but there was a substantial mass of stone work, rubble and well preserved archaeological features lying beneath this alluvium. This was traceable as a fairly unprepossessing low rise in the modern ground surface. It can be tentatively suggested that the orientation of linear wall lines revealed in the main trench indicate a match to the rectilinear anomaly apparent in the geophysics, and these may reflect a long building orientated with its long axis at right angles to the stream. A pronounced gully or channel was identified running through the mass of rubble in one area. A section through the gully located a large subterranean stone-lined feature, probably a drain. The drain implies some element of water management, possibly beyond that required in a normal domestic space, and it could be connected to a range of possible different activities. Samples taken from the drain will hopefully yield well preserved environmental evidence and may even have implications for the role of the site and its proximity to the Burn of Swartigill.

Near to the burn it was possible to link the previously evaluated archaeological remains present in the erosion front with those in the main trench and in several of the small test trenches, and to establish that certain previously recorded massive blocks of stone and other features were indeed parts of wall lines and wall faces seen more clearly in the main trench. A significant assemblage of diagnostic ceramic sherds including well made, decorated Iron Age pottery, was recovered from contexts both abutting, and overlying, the wall lines, and much of this ceramic material is identical to sherds recovered in the earlier stage of work. A quern rubber came from the rubble mass and a hammer stone from the fill of the drain feature. Slightly more surprising, given the

relatively modest scope and scale of the excavations but no less welcome, was the discovery of a copper alloy artefact. In appearance this was a small abraded triangular fragment abraded smooth but nevertheless preserving indications of a deeply set ‘cell’ perhaps for an enamel inlay. This would appear to have been a relatively valuable item from something like a brooch or a decorative fitting.

One of the test trenches that had been set-out to explore a curvilinear anomaly on the geophysics encountered a probable stone dyke that may date to the post-medieval period.

Archive: Local Museums Services (intended)

Funder: Caithness and North Sutherland Fund and Yarrows

Martin Carruthers – Archaeology Institute, UHI

(Source: DES, Volume 16)

ND 3210 4573 The site is located at the Burn of Swartigill, along the S side of the burn. An excavation was undertaken by the Archaeology Institute, UHI and the Yarrows Heritage Trust, 23–30 April 2017, to further investigate structural remains partially eroded by the Swartigill Burn and identified within earlier phases of excavation and geophysical survey.

The structural remains recorded during the excavation align with areas of high resistance identified in the previous earth resistance survey and form a large sub-circular structure with an internal area measuring c6m E/W by 5m N/S. A small number of artefacts were recovered, including a small number of prehistoric ceramic pottery sherds and a whetstone reminiscent of 10th- and 11th-century artefacts from Norway and Iceland, though further analysis of this find is required before its provenance can be confirmed. The presence of this artefact raises the possibility of Viking period or early medieval activity on the site which post-dates the demolition of the structure.

Deposits on the W side of the structure contained abundant inclusions of charcoal, charred grain and fragments of magnetic material. The latter may represent hammer-scale, indicating evidence for metalworking, though further analysis is required to confirm this hypothesis.

Archive: ORCA

Funder: Foundation Scotland: Tannach and District WInd Farm Charitable Trust

Martin Carruthers and Richard Barton – Orkney Research Centre for Archaeology

(Source: DES, Volume 18)

ND 3210 4573 Investigation this season, 20 August – 7 September 2018, extended the area of the previous excavation to the E and S, in order to further investigate the well preserved structural features defined during the 2017 excavation season (DES 18, 132). The excavation area in 2018 season consisted of an area 10m long SE/NW by 10m wide SW/NE. A 5 x 2.5m wide extension was excavated to the S of the main trench area.

The work aimed to define the extent of the structural features in relation to the earth resistance survey, establish the stratigraphic and chronological relationships of the structural features, and investigate the potential for preservation of in situ deposits.

This season of excavations identified that the earliest phase of activity on the site is likely to be a series of structural features truncated by the erosion at the edge of the Burn of Swartigill. Radiocarbon dating from deposits associated with these structures in previous seasons of excavation returned an early to middle Iron Age date (366 – 192BC).

The structures eroding from the burn section include a small cist feature, measuring 1.2m long by 0.6m wide and 0.45m deep. The cist had been partially destroyed on its N side by erosion of the burn bank. Despite the apparent damage to the feature, the lower deposits within the cist appeared secure and were sampled for analysis.

The structural remains within the eroding burn section were overlain by an ash rich deposit, which was in turn truncated by the construction cut for a revetment wall for a passage structure to the S.

Structure A represents a curvilinear passage building, which extended 10m across the full width of the excavated area on a SW/NE alignment on the W side of the trench and turning to the E. The passage was defined by a northern revetment wall on the N side with a curvilinear arrangement of boulders forming the southern wall. The passage measured between 0.7m wide at its narrowest point at the W end, and 1.9m wide to the E. The interior of the structure features a threshold stone at its W end, with a flagstone surface throughout the building. The flagstones formed the capping for a substantial drain running through the E/W portion of the passage, which gradually slopes to the E, where it widened into a sub-rectangular chamber.

Structure A was infilled by collapsed structural material and disorganised rubble deposits. Radiocarbon dates from deposits sealing the rubble infill of this structure collected in previous seasons of excavation returned a date of 198-47BC. The full extent of this structure extended beyond the E and W edges of the current excavation area.

Structure B was situated directly to the S of Structure A and was abutted by the rubble core of the southern boulder revetment of Structure A. Structure B consisted of a sub-oval structure with an internal area measuring 6m wide N/S by 7.5m long E/W.

The structure was defined by double-faced walls, with an entrance aperture on its E side. A possible hearth setting was identified within the centre of the structure, defined by an area of carbon rich ashy deposit within a circular stone setting. Further possible occupation deposits were identified in the interior of the W side of the structure. The interior of the structure is partially infilled by rubble material, which is in turn overlain by peaty deposits and alluvium.

Evidence for a third well-preserved structure was identified in an extension of the trench to the S of Structure B. Structure C was defined by an arrangement of edge set stones, at right angles to each other, forming the interior face of a chamber, backed by coursed masonry and rubble. Only a small portion of this structure was identified within the excavation area, with traces of a portion of the structure continuing to the W with a passageway between Structures B’s south wall and Structure C.

A significant assemblage of artefacts was recovered during this season of excavation, mainly comprised of prehistoric pottery. The majority of the pottery sherds were found in deposits within the eroding burn section. A number of hammer stones were also recovered from contexts across the site. A fragment of shale bangle with a D-shaped profile was recovered from a rubble deposit in close proximity to the eroding burn section.

Archive: NRHE

Funder: Yarrows Heritage Trust, E.ON, Eneco UK, Lybster and Tannach, Foundation Scotland, and Caithness Archaeological Trust

Rick Barton – Orkney Research Centre for Archaeology (ORCA)

(Source: DES Volume 19)