Excavation Iron Age The Cairns The Cairns Dig Diary 2019

The Cairns: Day 20 – the final day

The University of the Highlands and Islands research dig at The Cairns has now come to an end for this year. With the site safely covered up, it is time for site director Martin Carruthers to sum up...
Site excavation and recording completed and covered up for protection

The University of the Highlands and Islands research dig at The Cairns has now come to an end for this year. With the site safely covered up, it is time for site director Martin Carruthers to sum up…

Well we have reached the end of this season’s excavations at The Cairns! It’s been an incredibly rewarding season and we have learned a lot about the site.

We’ve been very busy finalising the recording of the features and buildings and then the great task of covering up the trench began.  Hundreds of tyres and many, many metres of plastic were moved around the site and placed with loving care to protect the site from the rigours of the weather for another year. 

Across all the areas of actively excavation we have made real progress, and one of the very satisfying reminders of that has been the number of return visitors to the site who have said they’ve seen real physical change to the site. Even the adverse weather hasn’t dented the spirits or the progress.

Broch origin stories

One of the most startling and very welcome developments is within the broch itself where we have reached the primary occupation levels in the west and north-east quadrants/rooms. This is very important in terms of our aims of fully excavating the entire suite of floors and occupation within the broch.  It means we are far closer to achieving this outcome than I imagined.

We will now be able reflect on the changes that have occurred to the layout and the use of the broch through time from the outset of its life to the very end.  Additionally, we should now be able to obtain radiocarbon dates for the earliest occupation in the broch.

It now appears that the major divisions of the room space represent the original layout and that’s important because they are very well preserved and convey a very clear and coherent impression of how movement and activity was organised in the broch.

Farewell from the remaining team on the last day of the excavation.

Within the western room of the broch we have seen that there is a very substantial focus of activity arranged around an impressive hearth, the setting for which is coming into view but there is so much rake out of hearth sweepings, and ashy flooring around it that we will be next season before it is entirely revealed.

In terms of artefacts from this area we have added a further piece of glass, a bronze ring and lots of pottery to add to last season’s glass beads and metal objects.  The glass objects are all imports to Orkney and ultimately the material for their manufacture derived from Roman sources. 

The tiny scrap of glass from the broch floor in the west quadrant/room.

It’s fascinating to see this obvious trace of interaction with communities on the Scottish mainland as well as with the Roman world. The landscapes of Orkney are often portrayed in the academic literature as tough and marginal places to eke a living from, but the imported objects are a welcome reminder of Orkney’s active participation in prehistoric geopolitics.

Bronze ring from the early phase floor of the broch.

The south-west extension

In the south-west extension area, progress has also been significant. 

Structure J is the principal building here, constructed directly in the lee of the southern wall-face of the broch. What had seemed to be a fairly small building in previous seasons can now be seen to be far more substantial and complex with its large multi-roomed interior.

The building sits within a revetment wall that has itself been built against the great construction cut or terrace for the broch.  We think this indicates the early nature of the village settlement and that it was largely constructed as a contemporary element alongside the broch.

If ultimately proven to be the case, this is significant in contributing to the debate about village planning and the primary nature of such extramural settlements!

Also in the south-western extension we continued to excavate the inner edge of the ditch. 

The ditch surrounds the site forming a large enclosure around 60 metres in diameter.  On the eastern side of this enclosure, the ditch splits in two to form a double line at the front of the settlement, and it is the innermost of these two ditch lines that we have access to in the south-wets extension. 

The ditch was again rich in finds this season, especially in animal bone but also stone tools and pottery.  On the edge of the ditch it became clear that there were several revetments added over time and these must have been intended to hold back the silty clay that we have found redeposited across parts of the buildings, indicating that it was subject to slippage and that this hill wash moved the clay around the site a little. This shows that the inhabitants of the site were trying to hold back the slope wash by constructing these revetments and that shows that they were maintaining the edge of the ditch and the inner bank of clay as a set of exposed earthen ground.

If they had allowed the grass to re-colonise the ditch and bank, then the slope-wash would probably not have occurred in this manner and been anchored by plant roots. 

Even this little detail is important as it appears that the broch community routinely maintained the enclosure and terrace. The enclosure must have been more visually prominent and vivid from a distance with its exposed yellow clay than it would have been if vegetated.

This just adds detail and colour to how we can visualise the site, as well as pointing to another set of tasks and procedures that the community routinely undertook, presumably in some numbers.

Down in the village

Trench areas M and Q make up a large, broad area around the North of the broch, stretching from immediately outside the front door of the broch around to the north-west extension that was made this year. New walls and entirely new buildings have emerged in this area so swift has been the progress made! 

There’s now a much more coherent sense of the shape and extent of previously identified buildings as well. We can now see that Structure O, a sub-rectangular building at the very front of the broch, just to the north of the entrance, is surmounted by the same rubble that clads the outside of the broch here, and this shows that the building was up and running for at least some of the period of the broch.

Its fourth (south) wall (only now visible) appears to respect the broch, stopping short of the pathway towards the broch front door and this fact together with O’s well-built double-faced walls make it a very good contender for another building that was constructed at the same time as the broch.

Meanwhile Structure R, a newly identified building is anchored on to O but constructed later, and itself opens on to Structure K.

Structure K is now shown to be a very large building (it’s the one that previously yielded lots of metalworking moulds and crucibles dating to around AD300), and we can see that it was in contemporary use with Structure R, because a common doorway and paving connects both buildings.

We’re now able to suggest very strongly that Structure O, N and M are primary with the broch, while Q, K and R, are subsequent constructions. K overlies the enclosure ditch and therefore this also points to the ditch being a broch period feature.  All of this phasing is probably best understood in diagrammatic form, so I’ve included a little schematic illustration of how it works.

A schematic illustration showing the main structures to the north-east of the broch and their phasing as we currently understand it

The souterrain

Looking along the souterrain passage as it makes a right-angle turn and enters the broch entrance passageway, which was itself reused as the chamber of the souterrain.

One of our aims this season was to deal with the deposits inside the souterrain, which lies on the eastern side of the broch. We excavated the deposits that in-fill the souterrain and took lots of soil samples to try to understand the composition of this in-fill.

What’s more, the way is clear for us to chemically analyse the floor of the souterrain to try to glean more information about how it was used.

A very odd feature of the souterrain seen in a previous season was the quern installation set up on the roof of the structure at its southern end. Essentially, two rotary querns had been set up inverted over an intentional aperture in the souterrain lintels. The central holes of the querns were aligned with the aperture, and the entire feature conveys the impression of being used to pour something into the underground passageway from above.

There are several instances of Iron Age querns reused in this way to form a porous lid on pits in wheelhouses in the Western Isles, and in one instance it was suggested that there may have been libations being poured into them! This season we were able to observe a very peculiar deposit located discretely and directly located beneath where the quern installation had lain.

Now that we have been able to acquire soil samples these will be subjected to phosphate analysis, amongst other analyses, to try to discern putative traces of the substance that was being poured into the hole in the roof – stay tuned to hear more over the next weeks and months! 

And finally…

In The Cairns broch.

All in all, it has been a very fruitful and enjoyable season, with a lot learned about the nature of the site, from its beginnings to the end, major features of the site such as the excavation of broch floors, the broch construction platform and the ditch will immeasurably help us to understand the character of the settlement, and the finds this year have been very rich and highly useful in a number of ways to elucidate issues relating to dating, the status of the community and their depositional practices.

Now some thank yous!

I’ll take this opportunity to thank the entire project team for their unstinting good humour, patience and enthusiasm. Without them the site would of course remain unexcavated, and it’s only through their sterling efforts that we begin to understand what was going on at the site more than 2000 years ago!

A second bronze ring from the broch floor.

This year the public have visited the site as before. We benefitted from a large number of very interested visitors, and they were very generous in their expression of support for the project. The funds will now be spent on important aspects of furthering the research, such as radiocarbon dating the beginning of the broch.

I would like to thank all of the visitors and donors, and for allowing us to communicate our findings at the site.

Finally, I would like to thank Charlie and Yvonne Nicholson and all of their family and friends in South Ronaldsay for their many acts of assistance and generosity. Our time at The Cairns is made possible, enjoyable and very amiable due to their great kindness.

Thank you!

Martin Carruthers, Site Director


  1. Can’t believe you are finished for this year already. I have so enjoyed your posts. Looking forward to next year’s excavations. Thanks for sharing and best wishes till next year!

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