Skaill, Castle Of Snusgar

HY21NW 54 centred on 2349 1891

The following areas were surveyed in June and July 2003 as part of the Birsay-Skaill Landscape Project.

HY 236 196 to HY 230 187 Bay of Skaill. Survey was concentrated in two areas: the mound on the N side of the bay known as the 'Castle of Snusgar' which was the site of the 1858 Viking silver hoard; and the immediate environs of Skara Brae within the World Heritage Site area to the S. The Snusgar survey started with 3D electronic topographical modelling - a flat platform on the NW of the mound was mapped, almost certainly the site where a stone building once stood (visible until the 18th century). Magnetometry confirmed that this prominent rise in the landscape is a major settlement mound with probable medieval, Norse and Neolithic components.

Survey around Skara Brae itself was relatively limited, but showed that an 'igneous dike' passes almost underneath the settlement, and that there are further archaeological features including linears and discrete anomalies both around Skara Brae and the large settlement mound to the W (HY21NW 30), which is currently suffering severe cliff face erosion. Two 30 x 30m magnetometry grids close to Skara Brae allowed a repeat of part of a 1973 geophysical survey, and this cast informative new light on the earlier data.

Report to be lodged with Orkney SMR and the NMRS.

Sponsors: Orkney Islands Council, Orkney Heritage, University of Oxford.

D Griffiths 2003

HY 236 196 Bay of Skaill. Resistivity survey.

Reports to be lodged with Orkney SMR and the NMRS.

Sponsors: HS, Orkney Islands Council, University of Oxford.

D Griffiths 2004

HY 236 196 Bay of Skaill. Magnetometry survey.

Reports to be lodged with Orkney SMR and the NMRS.

Sponsors: HS, Orkney Islands Council, University of Oxford.

D Griffiths 2004

HY 236 196 Bay of Skaill. Previous survey (DES 2003, 101) was concentrated on the mound on the N side of the bay, known as the Castle of Snusgar, which was the site of the 1858 Viking silver hoard. Gradiometry showed a dense concentration of magnetic anomalies in the Snusgar mound, which were provisionally interpreted as indicating that the mound is a multi-period archaeological feature.

Topographical and geophysical survey were extended considerably in 2004 in collaboration with the newly established geophysics unit at Orkney College. Twenty grids of resistivity (20 x 20m) were carried out on the Snusgar mound itself, and 34 grids of gradiometry were carried out on Snusgar, a neighbouring (lower) mound immediately to its NW, a mound cut by the road (HY21NW 23), and a further mound some 60m to the E of Snusgar. With the exception of the latter mound, all targets showed dense anomalies indicating archaeological potential: the concentration of multi-period sites around the N of the bay can now be expanded from one to at least three foci.

Two trenches were opened in the NE flank of the Snusgar mound. The subsidiary trench on the furthest E flank of the mound was intended to provide a soils history in profile.

The main trench, nearer the summit of the mound, encountered a spread of industrial waste: date as yet unknown, but may be relatively recent, possibly from kelp burning as burnt seaweed was retrieved from environmental samples. Beneath and outwith this concentration were laminated sand/occupation layers surrounding stone structures. Some of these were disturbed and fragmentary, but there was a large E-W double-faced wall, 1.2-1.5m wide, which corresponds with the E-W structural features observed in the 2003 gradiometry plot, and which were provisionally interpreted as part of the phase which gave rise to the notion of the Norse 'castle'. The occupation layers, which may be outcast midden from a settlement core immediately to the W of the excavation area, were associated with a range of (mostly bone) finds of Viking period type, and a green banded whetstone with parallels associated with high-status Viking sites in Scandinavia. Bone preservation was good and a large range of animal bone was retrieved, with some fish bone from lower occupation layers. Environmental samples indicate that oat cereal grain, six-row hulled barley and flax were present, along with burnt peat. Other significant finds include polished bone pins, antler comb fragments, bone textile utensils, a copper-alloy toilet implement and a small amount of iron slag.

Progress was made in characterising this upper phase of the mound - part or all of which was resting on a substantial layer of windblown sand, but time did not permit deeper investigation within and beneath this windblown layer.

Reports to be lodged with Orkney SMR and the NMRS.

Sponsors: HS, Orkney Islands Council, University of Oxford.

D Griffiths 2004

HY 2365 1962 A research project on building landscape context for coastal erosive areas in zones affected by significant wind-blown sand was undertaken from 28 July–18 August 2007. Previous survey in 2003 and further survey and excavations in 2004–6 at the Bay of Skaill was concentrated on N bay environs, focused on the mound on the N side of the bay known as the ‘Castle of Snusgar’ (the probable site of the 1858 Skaill Viking

silver hoard). Gradiometry showed a dense concentration of magnetic anomalies in the Snusgar mound and neighbouring mounds. The concentration of multi-period ‘mound’ sites around the N of the Bay can now be expanded from one to at least five foci (excluding Broch of Verron, HY21NW22). The excavation area opened as a test-trench in 2005 on mound to the E of ‘Castle of Snusgar’ revealed Viking or Norse period middens stratified over a substantially well preserved stone building with in situ orthostatic internal divisions or ‘furniture’. This had filled with windblown sand (which contributed to a diffuse gradiometer response in 2004). This was further excavated in 2006 and extended in 2007. A coherent spread of stone walls has now been revealed standing up to 0.5m high with clearly defined internal and external areas, stone flagged floors and

entrances. Finds suggest a Viking/Late Norse date, including an extremely well preserved decorated antler comb from a sealed context under a flagged floor. A series of OSL samples are currently being processed at the Research Laboratory for Archaeology, Oxford University, and a radiocarbon application for a series of dates is pending.

Bone preservation was good (currently being assessed by Dr I Mainland, Bradford University). Environmental samples were floated and processed on site and are being assessed for archaeobotanic evidence and radiocarbon potential by Dr D Aldritt, GUARD, Glasgow. The finds are being conserved on behalf of Historic Scotland by AOC Conservation Services, Edinburgh.

Data Structure Report deposited with HS, Interim Reports to be deposited with Orkney SMR, Orkney Museum and RCAHMS. Archive presently in Room 317, OUDCE, Oxford University.

Funder: Historic Scotland, Oxford University.

HY 2365 1962 This project focuses on building landscape context for coastal erosive areas in zones affected by significant windblown sand. Work from 2–30 August 2008 built on the previous survey (2003) and survey and excavations (2004–7) at the Bay of Skaill, which concentrated on N bay environs and focussed on the mound on the N side of the bay known as the ‘Castle of Snusgar’, which was the probable site of the 1858 Skaill Viking silver hoard. Gradiometry showed a dense concentration of magnetic anomalies in the Snusgar

mound and neighbouring mounds. The concentration of multi-period ‘mound’ sites around the N of the Bay can now be expanded from one to at least five foci (excluding Broch of Verron, RCAHMS HY21NW 22).

The excavation area opened as a test trench in 2005 on the mound to the E of ‘Castle of Snusgar’, revealed Viking or Norse-period middens stratified over a well preserved stone building with in situ orthostatic internal divisions or ‘furniture’. This had filled with windblown sand, which contributed to a diffuse gradiometer response in 2004. This was further excavated in 2006–7 and extended in 2008.

A coherent spread of stone walls has now been revealed standing up to 0.5m high, with clearly defined internal

and external areas, stone flagged floors and entrances. Immediately to the N of the buildings exposed in 2005–7 (continued in 2008), the central section of a much larger bow-sided longhouse was exposed, with stone flagged floors, a central walkway and box benches at the sides. Strong evidence for spatial zoning in the character of deposits and a stub wall indicated the division between animal and domestic occupation. Finds and a coherent group of radiocarbon dates (SUERC, 2008) indicate a Viking/Late Norse date between

cAD 1000–1200, which has been confirmed by a series of OSL samples processed at the Research Laboratory for Archaeology, Oxford University.

Outside the buildings exposed in 2005–7 was a square ‘yard’ area which was heavily burnt and contained very large quantities of metalworking waste, ferrous and non-ferrous slag.

Bone preservation was good, and bone is currently being assessed by Dr I Mainland, Bradford University.

Environmental samples were floated and processed on site and are being assessed for archaeobotanic evidence and radiocarbon potential by Dr D Alldritt, Glasgow.

The finds are being conserved on behalf of Historic Scotland by AOC Conservation Services, Edinburgh.

A geophysical survey was begun at Marwick Bay (continuing).

Archive: Oxford University. Report: HS, Orkney SMR, Orkney Museum and RCAHMS (intended)

Funder: Historic Scotland and Oxford University

David Griffiths (Oxford University), 2008

HY 2365 1962, HY 2283 2399 and HY 2300 2410 This project focuses on building landscape context for erosive coastal areas with significant windblown sand. Work from 20–29 June 2009 focused on the mound complex on the N side of the Bay of Skaill. Gradiometry and GPR showed a dense concentration of magnetic anomalies which were subjected to selective excavation in 2004–8. The concentration of multi-period ‘mound’ sites around the N of the Bay can now be expanded from one to at least five foci (excluding Broch of Verron, RCAHMS HY21NW 22 and RBW HY21 12, Verron 2). No excavation took place in 2009 but geophysical surveys

were continued and extended, connecting with the previous survey of the WHS buffer zone to the S (Orkney College Geophysics Unit).

A geophysical survey was begun at Marwick Bay in 2008 and continued in 2009. The chapel (SAM 2934) produced strong magnetometry and resistivity plots. Survey, characterisation, recording and soil sampling works also took place on the eroding settlement mound on the shore front of Marwick Bay (SAM 2884 – termed ‘Viking house’ by RCAHMS). Samples and radiocarbon dates will be processed in 2010.

Archive: OUDCE, Oxford University. Report: Historic Scotland, Orkney Museum, Orkney SMR and RCAHMS

Funder: Historic Scotland, Orkney Islands Council and Oxford University

David Griffiths – Oxford University

HY 2365 1962, HY 2283 2399 and HY 2300 2410 This project focuses on building landscape context for erosive coastal areas with significant windblown sand. Work from 20–29 June 2009 focused on the mound complex on the N side of the Bay of Skaill. GPR showed a dense concentration of magnetic anomalies which were subjected to selective excavation in 2004–8.

Funder: Historic Scotland, Orkney Islands Council and Oxford University

David Griffiths – Oxford University

HY 2365 1962, HY 2283 2399 and HY 2300 2410 This project focuses on building landscape context for erosive coastal areas with significant windblown sand. Work from 20–29 June 2009 focused on the mound complex on the N side of the Bay of Skaill. Gradiometry showed a dense concentration of magnetic anomalies which were subjected to selective excavation in 2004–8.

Funder: Historic Scotland, Orkney Islands Council and Oxford University

David Griffiths – Oxford University

HY 2365 1962 This project focuses on building landscape context for erosive coastal areas with significant windblown

sand. A previous survey in 2003 and further survey and excavations in 2004–8 concentrated on the N bay environs.

Gradiometry showed a dense concentration of magnetic anomalies in the ‘Castle of Snusgar’ and neighbouring mounds. The concentration of multi-period ‘mound’ sites around the N of the Bay of Skaill can now be expanded from one to at least five foci (excluding Broch of Verron, HY21NW 22).

Work from 24 July–30 August 2010 focused on an area initially opened as a test trench in 2005 on the mound 100m to the East of ‘Castle of Snusgar’, which had revealed Viking and Norse period middens stratified over a well preserved stone building with in situ orthostatic internal divisions or ‘furniture’. Excavation continued in 2006–8 and was extended in 2010. A coherent complex of stone walls has now been revealed standing up to 1m high with clearly defined internal and external areas, stone flagged floors, yards and entrances. External to the buildings exposed in8 2005–8 (now viewed as outbuildings) was a square ‘yard’

area which was heavily burnt and contained very large quantities of metalworking waste, ferrous and non-ferrous slag. This was fully excavated in 2010, revealing a series of four well preserved bowl hearths separated by laminated clay floors, and producing large amounts of ferrous and some non-ferrous metalworking residues. These are now being assessed at NMS. Radiocarbon dates taken in 2008 indicate that the upper fills of the metalworking features contain charred material from around AD 1000. Outside and to the SE of the frequently rebuilt ancillary buildings were rich, deep midden deposits. Underlying these were a drain system and an earlier phase of stone buildings of a less rectilinear, more curvilinear plan, perhaps dating to the early- or even the pre-Viking period.

In 2008 the central section of a much larger longhouse, with walls standing over a metre, was exposed immediately to the N of the buildings excavated in 2005–7. Connected to them by a staircase and flagged yard. In 2008 the longhouse was seen as a stone flagged entrance area, a drain and central walkway to the E, and box benches and hearth deposits to the W. Strong evidence for spatial zoning in the character of deposits and a stub wall indicated the division between animal and domestic occupation. Finds and a coherent group of radiocarbon dates (SUERC, 2008, 2009) provided a Viking/Late Norse date between AD c1000–1200. The longhouse building was almost fully exposed in 2010 (with only a small section in the W end remaining unexcavated between two trenches). Both ends of the building were identified, confirming it at 23.6m long, with intact stone side benches, laminated floors and hearths, sunken stone-lined box-pits, and symmetrically sited postholes. The building was constructed in at least three phases; beginning with a simple bow-sided longhouse, later extended E to create the byre/working area (when the stub wall was probably built), and W, with a substantial rectilinear longhouse style extension to the living area. The western extension was constructed with wider side-benches and cooking hearths in a central kerbed zone. The internal entrance passage between the dwelling area and byre was well preserved with the door socket in situ. All finds and samples were 3-D plotted and stratigraphic analysis, phasing and further radiocarbon dating are under

way. Animal bone preservation was good and environmental samples are being assessed. Finds are currently undergoing conservation.

Archive: Currently with University of Oxford. Reports: HS, Orkney

Museum and RCAHMS

Funder: Historic Scotland, University of Oxford and Orkney Islands

Council

HY 2365 1962 and HY 2460 2700 This project, which began in 2003, focuses on building landscape context for erosive coastal areas with significant windblown sand. Geophysical survey and targeted excavation have taken place at three bays and their hinterlands at Birsay, Marwick and Skaill.

The Brough of Birsay, the Point of Buckquoy, parts of Birsay Links, and areas surrounding the bay frontage at Marwick were all surveyed 2003–10. Survey and excavations in 2003–10 at the Bay of Skaill concentrated on the N bay environs. Gradiometry showed a dense concentration of magnetic anomalies on a group of five large settlement mounds on the northern margins of the Links of Skaill, immediately NE of the bay frontage. These have been tested selectively by excavation.

Excavations in 2004–10 revealed Viking and Norse period middens stratified over well preserved stone buildings on two large settlement mounds: ‘Castle of Snusgar’ and ‘East Mound’. On ‘East Mound’, a coherent complex of stone structures surrounding a longhouse 26.3m in length was revealed in 2010, with walls standing up to 1m high with clearly defined internal and external areas, stone flagged floors, yards, flights of steps, and entrances. Radiocarbon and OSL dates from samples taken in 2004–8 indicated a general chronology AD c950–1200 for occupation layers on ‘Snusgar’ and ‘East Mound’. Further refinements in 2011, from dates taken from occupation levels and metalworking hearths in 2010, and ongoing statistical analysis by Derek Hamilton of SUERC, suggest the main domestic occupation phase of the longhouse and its associated buildings on East Mound is dated to a relative narrow chronological range in the early 11th century AD.

In August 2011 a 15 x 2m trench was excavated on the sloping periphery of the settlement complex to test the mound/soil formation deposits in this area. As with other peripheral interventions on the edges of these settlement mounds, a complex build up of laminated sands and buried ground surfaces was exposed, trending towards waterlogged silts nearest to the burn edge, and showing indirect settlement influences. These layers were sampled and recorded in section and further soil, environmental and dating analyses are in process. A 2 x 2m test pit was also machine excavated on a possible smaller mound feature to the SE of ‘East Mound’ on the other side of the burn. This area had been surveyed using magnetometry in 2005, with generally negative results, and the test pit confirmed a depth of clean windblown sand to 2m, the lowest practicable excavation depth in such soft and unstable ground, eliminating the possibility that this particular ‘feature’ is archaeological in origin.

Geophysical survey was undertaken using a Bartington G601-2 gradiometer and a Geoscan RM15 twin probe resistance meter, on 20m grids taking readings at 0.25m with 1 separation, and the data was processed using Archaesurveyor™ software. In 2011, a possible mound feature 100m to the E of ‘East Mound’ at the Bay of Skaill was surveyed with both magnetometer and resistivity, having been topographically surveyed in 2010. The site was found to be badly contaminated by modern activity but some potential was highlighted at the uppermost part of the feature where a stone dyke crosses it. A surface survey and geophysics where also undertaken on the one remaining scheduled site yet to be investigated within its study area: the mound known as Saevar Howe (SAM 1373) on the southern edge of Birsay Links. This is another large sandy settlement mound, known to be of significant archaeological interest, having been excavated on two previous occasions in 1862 and 1977, producing evidence of Pictish and Norse burials and structures. Its current condition is poor, suffering weathering and deflation, and animal erosion by rabbits and cattle. A large deflation hollow occupies the centre of the mound, which partly may be due to previous excavations, and which is strewn with metallic and other debris dating from WW2 and later. The survey aimed to further characterise its remaining archaeological importance and assess its vulnerability to further degradation. A topographic model was compiled using a Leica 400 Total Station and Surfer™, which was supplemented by 0.64ha of combined magnetometer and resistivity survey. A large rectilinear feature occupies the upper area of the mound, surrounding the deflation hollow, which is of potential archaeological significance. This possibly represents a large, coherent stone feature which has probably been made visible magnetically by a build up of midden around its exterior. Elsewhere on the mound, and particularly on its northern side, are more diffuse amorphous anomalies of a type which have become familiar on several such large sandy settlement mounds already surveyed at the Bay of Skaill. These are caused by multiple layers of organic midden and windblown sand producing a combined magnetic response. Resistivity and 3D survey modelling have helped to give these some depth and topographic resolution. This summary is based only on the first stage of visualising the results: further processing and refinement is ongoing.

Archive: University of Oxford (currently). Reports: Historic Scotland, Orkney Museum and RCAHMS

Funder: Historic Scotland, Oxford University and Orkney Islands Council

University of Oxford, 2011

HY 2365 1962 and HY 2460 2700 This project, which began in 2003, focuses on building landscape context for erosive coastal areas with significant windblown sand. Resistivity surveys have taken place at three bays and their hinterlands at Birsay, Marwick and Skaill.

Archive: University of Oxford (currently). Reports: Historic Scotland, Orkney Museum and RCAHMS

Funder: Historic Scotland, Oxford University and Orkney Islands Council

University of Oxford, 2011

HY 2365 1962 and HY 2460 2700 This project, which began in 2003, focuses on building landscape context for erosive coastal areas with significant windblown sand. Gradiometry survey has taken place at three bays and their hinterlands at Birsay, Marwick and Skaill.

Archive: University of Oxford (currently). Reports: Historic Scotland, Orkney Museum and RCAHMS

Funder: Historic Scotland, Oxford University and Orkney Islands Council

University of Oxford, 2011