Excavation Iron Age The Cairns

The Cairns dig diary – day six

A summary of week one and a look at what lies ahead.
Aerial view of The Cairns excavation site during week one of the 2023 excavation. (Tom O'Brien)
Aerial view of The Cairns excavation site during week one of the 2023 excavation. (Tom O’Brien)

A summary of week one and looking ahead…

It’s been a very wet day today – a real transformation of the very sunny, warm weather we’ve become almost used to lately.  We therefore had to bid the site adieu early lest we did it, or ourselves, a bit of damage amidst the sustained rain.

I have to say that the site has been so dry that a little precipitation is just what it needed to reveal subtle colour changes in soils and make the stonework pop against the deposits, so hopefully tomorrow will be better weather and we’ll see a real improvement in the appearance of the site also.

As it’s the Monday of our second week on site, I thought I’d do a little round-up of what we accomplished last week and what we have to look forward to…

In the broch

The broch interior.

A major focus for attention this year, the broch (Structure A) is a core part of the site.

We intend to peer into areas of the broch interior that we have not substantially excavated in previous seasons. To that end, we began the week exploring the North Room. This is a large arc of a room, set around the northern interior of the broch. This room includes the sub-floor feature of the well.

In the western part of the room there even remained rubble from the infill of the broch. We began to excavate this rubble and beneath it was where what is probably the star find of the week – the massive whale rib.

The whale rib, lying on top of a slab of dressed stone. (ORCA)
The whale rib, lying on top of a slab of dressed stone. (ORCA)

The rib may well be another part of the previously encountered whalebone assemblage. This comprised over 20 pieces of whalebone that DNA analysis proved to be from fin whale and probably from the same individual – and all dating to the end of the broch. In which case, this would show the spread of this whale carcase extended into the North Room of the broch also.

The removal of the last rubble here showed that we’re probably on the brink of confirming that there is a further subdivision within the broch interior. The uprights which are now emerging suggest we will have to assign a North-West Room to the broch. This shows how thoroughly partitioned the broch ground floor was.

The large saddle quern being removed from the interior of the broch last week. (Kevin Kerr)
The large saddle quern being removed from the interior of the broch last week. (Kevin Kerr)

Another key area that we have hitherto spent less time in until this field season is the adjacent Central Room. Here the removal of collapsed slabs was a prelude to establishing a sampling grid. I was really pleased to see that rather than leave us with a sense of absence, the removal of these slabs provided conclusive proof of the layout of the Central Room in the form of in situ low uprights defining the area even more clearly.

It shows that in its current form, the Central Room is indeed, what we thought it was – a largely corridor space, that permitted access to the West and North Rooms respectively. We are closing in evermore on the detailed access arrangements around the various elements of the space in the broch interior.

Under and around the toppled uprights of the Central space were querns, shells, fishbone and antler points: floor/occupation deposits giving insight into what richness probably awaits us in this area.

In the week ahead, we’ll really begin excavating these deposits and who knows what else we’ll find!

Structure O

Structure O, our village building outside the broch entrance, is another focus of work this year and our intention is to further characterise this building: its form and chronology.

The task, ahead of that, however, is to fully record the revetment and paving that overlies a good chunk of Structure O. We think this wall and paving dates to around the AD400s or 500s.

From the work undertaken last week it appears that this wall may have been a really quite fast build. Although it is composed of some fairly impressive blocks of large masonry, the wall is quite an irregular build, with quite ragged and small pieces of stonework elsewhere.

The paving associated with the revetment wall capping Structure O that probably dates to the fourth/fifth century AD. (ORCA)

With nothing to suggest that the wall endured for a very long time, or had multiple stages of rebuilding, it would seem it was constructed quite hurriedly and with perhaps a fairly short purpose in mind. It certainly seems not to be the kind of wall that could have carried much weight or height and so we think it relates to an outdoor, unroofed space.

It does indeed seem to form part of a series of three parallel revetment walls (each with its accompanying paving), two of which we have previously excavated in this area. These walls seem designed to demarcate a space on the “broch-mound” – the ruinous remains of the broch – probably partially turfed over by that time but remembered nonetheless perhaps, and still physically conspicuous.

What these walls and platforms were actually used for eludes us for now, as there’s little evidence to go on but in some ways, they resemble tiers of masonry around much earlier chambered cairns, or the revetments and paved areas at Mine Howe, East Mainland, Orkney, a site previously excavated by UHI Archaeology in the early 2000s.

A final thought on the paved area: as we cleaned up the paving and exposed it fully a strange area in the centre emerged that does not look like the rest of the slabs. It is composed of more irregular blocks of stone bounded, in part, by edge-set stones. This looks like some kind of feature set in the centre of the paved area and we will have to excavate this after we’ve fully recorded the paving.

Perhaps it will hold a clue to what these revetted platforms were used for…

The lamb remains recovered from rubble infill of Structure O. (ORCA)
The lamb remains recovered from rubble infill of Structure O. (ORCA)

In the part of Structure O not sealed by the overlying revetment and paving, Luci was tasked with trimming back the rubble infill and here she encountered an animal bone group (or ABG) composed of pretty much the entire skeleton of a lamb and another medium-sized mammal.

Back in the 2017 field season, we encountered a well-preserved cattle spine in this same rubble and it was subsequently C-14 dated to the later second century AD – the time around the end of the broch. It looks like these two new ABGs may also be depositions marking the abandonment and back-fill of Structure O.

The ‘frontage’ outside the broch

The “Elder Assemblage’ in 2016. (ORCA)

Lying between the broch outer wall-face and Structure O, is what we’re terming the frontage.

In this area we previously encountered large volume of shell and animal bone and, of course, the remarkable human jaw, and whalebone vessel deposit (‘The Elder Assemblage’).

The jawbone found as part of the deposit outside the broch in 2016.

You might recall that our purpose in this area this season is to further explore the context of the Elder assemblage, but also to characterise the midden that clearly sat outside the broch entrance during the second and possibly first Centuries AD, or even earlier.

This will be a highly valuable source of information about the lifestyle, particularly the diet and economy of the broch household.

Simply put, last week, Holly’s team working here “played a blinder” by very quickly excavating overlying rubble and broadening out the amount of area we have available to work in and explore.

The midden, conspicuous by the patches of shells strewn across it, turns out to be substantial and more extensive than we had thought – good news as it seems to contain even more information, therefore.

For the beginning of this week, we will be able to establish our strategy to excavate and sample this important source of evidence for life in the broch during the Iron Age, complementing the information coming out of the broch itself.

Structure E

Post Broch structures.

We always have a least one “break-out” area beyond the main planned focus of work each season at the Cairns.

Usually, we branch out to this region for a mix of practical reasons and to provide additional experiences for the varied team of diggers. For now, this additional, but important, supplemental area is the south-eastern fringe of the main trench.

Here, the remains of little walls and uprights have slowly emerged from previous season’s work, but it has been difficult to really interpret this set of features and it has lacked any sense of cohesion until now.

Anthea, Deryck, Michael and Ole, working in this zone, have really brought it on and we can see there are a continuous series of semi-circular chambers forming a multi-cellular building, itself an extension of Structure E – a Late Iron Age or Pictish building constructed and in use in the first half of the seventh century AD.

The 'Shamrock' building at the Broch of Gurness, with the broch in the background. (Sigurd Towrie)
The ‘Shamrock’ building at the Broch of Gurness, with the broch remains in the background. (Sigurd Towrie)
The roch of Gurness 'Shamrock' building. (Sigurd Towrie)
The roch of Gurness ‘Shamrock’ building. (Sigurd Towrie)

These cells resemble the similarly dated “‘Shamrock” building at the Broch of Gurness, in Orkney’s West Mainland, but perhaps even more so a set of enigmatic structures on the northern coastal fringe at Gurness that are thought to have been truncated by coastal erosion, and which were not clearly understood during the excavations in the 1930s.

The important contribution that our emerging multi-cellular remains of Structure E can make to our understanding of these interesting but enigmatic semi-circular features and buildings is therefore high.

Not bad for our “wild-card”, break-out zone this season.

Overall, the first week of activity on site has delivered a fantastic mix of nice finds, important realisations, and learning new things about the generations of people who lived here at The Cairns during the Iron Age.

Martin Carruthers
Site Director