Excavation Iron Age ORCA Swartigill

Burn of Swartigill excavation 2021 – week one update

We are one week into this season’s excavation at the Burn of Swartigill, Caithness, and it’s time for an update on progress on site.

By Rick Barton

We are one week into this season’s excavation at the Burn of Swartigill, Caithness, and it’s time for an update on progress on site.

After the covers were removed last Monday, a mechanical excavator was brought in to extend the trench to the east and south. Straight away, we encountered structural remains in the south-west corner of the site.

Work commencing at the Burn of Swartigill site after the machine excavator had finished stripping the topsoil. (Bobby Friel/@takethehighview)

Previous years of excavation have identified that the deposits and structures within the burn section have been truncated by the construction of a souterrain, Structure A. This year, we will be looking at these relationships in more detail to try and define the form of these structures and recover material form deposits partially eroded by the burn to better understand this part of the site.

Site assistant Calum Hall and ORCA project officer Rick Barton discussing the excavation of the burn section.

Site assistant Calum Hall has been working in the area where the souterrain cuts into the earlier deposits.

Travis Lowe is an Archaeology SVQ student from University of the Highlands and Islands Archaeology Institute, and he has joined us at the Burn of Swartigill to gain some extra site experience.

He has been excavating some of the rubble that appears in the eroding bank of the burn and has encountered an area that contains a cache of pottery from what appears to be from a single vessel. This area of the site has always been rich in cultural material, though Travis’s finds appear to represent the remains of is a little unusual. Watch this space for updates.

Travis Lowe recording a pottery spread.

In the western extension of the site, we have been looking to establish the extent of the structures identified at the west end of the souterrain, Structure A.

Mary Renshaw excavated this area back in 2019 and has returned this year, having graduated from the UHI Archaeology Institute with a BA in Archaeology, to continue the investigation. She has been assisted by Archaeology Institute BA undergraduate Alannah Edwards and have been working tirelessly to excavate through the alluvial deposits that have shrouded the entire site. Their work has been rewarded with the appearance of wallheads for structural features and deposits rich in charred, organic material.

Mary and Alannah excavating in the western extension.

In the south-west corner of the site, the machine excavation quickly uncovered a north – south orientated alignment of stone. Husband and wife team, Deryck and Anthea Dean, wasted no time getting stuck into defining this feature and it soon became clear that this feature represents tumble from a wall.

Anthea, who is currently undertaking an MLitt in Archaeology with the UHI Archaeology Institute, noted that the feature appears to turn to the east. This would correspond to an area of high resistance detected during the geophysical survey of the site, and is likely to be related to Structure C – a feature characterised by the “ripple” stone forming an upright in its southwest corner.

New structural features emerging in the south-west corner of the site.
Anthea investigating the structure appearing in the south-west extension.

In the centre of the site, we are preparing to excavate some of the occupation-type deposits in Structure B. In previous years we have caught tantalising glimpses of deposits rich in charred, organic material, which is likely to represent a phase of secondary re-use of this structure.

Before we can start digging these deposits, however, we need to complete the process of recording them. This process can be painstaking, but site supervisor Holly Young has made short work of gridding out and planning this large structure and is ready to start investigating them in greater detail in the coming days.

Holly planning Structure B.
Structure B plan. Swartigill. (Holly Young)
Holly’s completed plan of Structure B. (Holly Young)
Floor surfaces emerging in Structure B.
George Watson looking at the drone screen with Bobby Friel.

We were delighted to welcome Caithness resident and archaeological enthusiast George Watson to site on Thursday. After George retired from Dounreay Nuclear Power Plant, he travelled all over Caithness visiting heritage sites and has accumulated an enviable understanding of the cultural heritage of the region.

On his first visit to the Burn of Swartigill, we spoke at length about the region’s rich cultural heritage, and how Swartigill was similar, and yet different, to numerous other sites in the area. George was particularly interested in how the landscape might have changed in the years since the site at Swartigill was occupied.

ORCA Project Officer Bobby Friel flew his drone over the site so that George could see the site from a higher vantage point.

We are extremely grateful to George for taking the time to come and visit us, and to George’s daughter Katrina, as well as Catherine and Steven from the Thrumster estate for their assistance in making his visit possible.

Aerial view of the Swartigill site. (Bobby Friel/@Takethehighview)

There is still plenty of time to come and see the site and get involved in the excavation. We will be working on site every day until the Wednesday, September 1, after which we will be taking a short break, returning on Monday, September 6. The final day of excavation will be Tuesday, September 14.

Visitors are welcome between 9am and 4pm.

If you would like to get involved with the dig as a volunteer, please email us at Enquiries.ORCA@uhi.ac.uk. No previous experience is required.

The site is changing every day, so be sure to keep an eye on our dig diary and the Yarrows Heritage Trust website, www.yarrowsheritagetrust.co.uk.


  1. Has the “ripple stone” been found anywhere else i.e. other sites in Caithness? It looks rather fascinating and unusual. Also do you anticipate this project continuing to the 2022 season also? Thank you.

    1. From site director Rick: “I believe the ripples on the stone are fossilised lake or river bed, and potentially relate to when the area was part of Lake Orcadie, about 350-400 million years ago. These sediments are mainly fine grained sandstone, siltstone and mudstone, and I believe it is not uncommon to find the deposits forming in ripples.

      For me personally, I have seen these kinds of deposits in situ in Orkney, specifically along cliffs to the west of Scapa beach, and in the South Mainland of Shetland at Exnaboe, where there are some fantastic former river sediments containing fossilised fish.

      This is only the second time that I can think of that I have seen this kind of ripple stone purposefully incorporated into a structure. The other example was as the basal slab of the stone lined tank at Cruester burnt mound on Bressay, Shetland. In this situation, I feel that the watery ripple effect on the stone would have had some special significance, since these tanks were undoubtedly used to hold water.

      Structurally speaking, these kinds of sedimentary rock do not lend themselves to substantial or load bearing architectural features. They are not particularly hard, and degrade or laminate relatively quickly. Most of the rest of the stone used in the structures at Swartigill of are a much denser and more solid sandstone formation, with a high proportion of sub-rounded boulders which may be derived from glacial diamicton.

      I will be making more enquiries about the geological origins of the stone on the site once the season is complete, with contributions from some more expert voices than my own.”

      We hope the Swartigill project will continue in 2022.

  2. Thank you so much for this reply. Very, very fascinating. I am just an enthusiast and hope to be able to offer my volunteer services next year, world travel permitting. I had planned to come in 2020, and 2021, but that obviously did not work out. Well done — the photographs and documentation are epic.

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