Excavation at the Iron Age site at the Burn of Swartigill, Thrumster, Caithness, is a collaboration between the University of the Highlands and Islands Archaeology Institute and the Yarrows Heritage Trust.
The excavations have provided a glimpse of everyday life in Iron Age Scotland – but a life that does not centre on the monumental architecture of the brochs.
The site was first investigated by members of the Yarrows Heritage Trust and CFA Archaeology in 2004, after structures were noted eroding from the bank of the burn.
In 2012, concerned that valuable archaeological evidence could be lost the trust recorded the eroding section. They discovered the remains of structures and deposits containing ceramics, which appeared to be Iron Age in form.
In 2014, ORCA Archaeology undertook a geophysical survey of the site, combining magnetometry, earth resistance and ground penetrating radar. This confirmed the likely presence of substantial structures and evidence of occupation at the site.
ORCA returned in 2015 to do some small exploratory work and the excavation has continued to expand from there. In multiple seasons of excavation the team, including professional archaeologists, local community volunteers and students, have uncovered the remains of a settlement that spans over a thousand years – from c350BC until AD945.
The site
In 2021, excavation revealed that the site comprised two roundhouse-type structures, as well as a souterrain.
These buildings were designated as Structures A, B and D. There were also traces of other buildings, either partially truncated or concealed by the later roundhouses and souterrain. These were designated as Structure C, E and F.
The Structures
Structure B – A sub-circular building. Radiocarbon dates for the occupation surface in the centre of this structure placed activity in the Early Medieval period, between the mid-9th and early 10th century. Some of the finds from this building provided clues about this later phase of activity, such as a bar-shaped whetstone with a distinctively Viking appearance.
This re-use of the structure appears to have occurred quite late in the life of the settlement. The walls of Structure B were significantly reduced, with rubble partially infilling the building. The rubble was cleared to create a temporary living space, with a hearth and post-holes to support a roof.
This may represent very transient activity. Perhaps a place for a farmer to rest while their livestock took water from the burn or a convenient camping spot for folk working out in the landscape.
This location has been used in this way for hundreds of years and into modern times. Locals speak of having picnics and campfires in this sheltered spot while peats were being cut out on the moor.
Structure A – The souterrain passage. We have confirmed that the cell at the west end of the souterrain is a later addition and the passage was originally linked to other buildings to the west.
Structure C – A small chamber with edge-set stone – the remnants of an earlier building incorporated into the later walls and entrance passage of Structure D. It is possible this chamber could significantly pre-date the other buildings on the site, but there is much work to do to investigate the feature and determine its date and function.
Structure D – A building with similarities to Structure B, another building which has been extensively modified. Both have hearths set within a horseshoe shaped kerb and were originally accessed through a passage leading to the east. The flagstone surfaces of these passages are linked with the courtyard area on the east side of the settlement.
Structure F – The earliest dated elements of the site, which were abandoned during the early Iron Age. The rubble that infilled this structure is interspersed with large amounts of prehistoric pottery.
Structure G – We are just starting to investigate the upper layers of this building. At some point Structure G was linked to Structure D, but in its later life the shell of the building was re-used and incorporated into later Structure E, with a roughly laid cobble surface supporting a large grinding stone
The area
The Burn of Swartigill is situated within the Yarrows, an area recognised for the excellent preservation of cultural heritage sites dating from the Neolithic to the Medieval period.
The late Iron Age settlement site of Thrumster is approximately 1km to the west of the site, further upstream of the Burn of Swartigill. The Thrumster site is characterised as a “wag”, which is defined as a post-broch structure, mainly found in Caithness, and characterised by a rectangular building form possessing two rows of orthostats forming a central aisle. The settlement is visible as a low mound, approximately 20 metres in diameter, with the remains of solidly constructed drystone wall footings visible in the top.
Two broch sites are situated within close proximity to the site.
The broch of Thrumster Mains is 1.3km to the south-east of the site and the Broch of Yarrows, along with a range of complex secondary structures including “wags”, is 2.5km to the south-east on a spur on the edge of the Loch of Yarrows.
The Burn of Swartigill site is also near two medieval farmsteads, which sit within an identified medieval farming landscape.
The first is approximately 30m to the north-west of the site and is comprised of a heavily robbed-out range with a smaller building and a set of run rig cultivations. The second is on the southern edge of the meltwater channel, approximately 160m to the south-east of the site. This farmstead is also comprised of a heavily robbed building and has an enclosure situated immediately to the east, with field system composed of pens and embankments to the south and east.
It was initially thought that the Swartigill Burn site represented a mill dating from the same period as the Swartigill township, and was included in the original record for this site.