Excavation Iron Age The Cairns

The Cairns dig diary – day eleven

Midway through the 2023 dig, site director Martin sums up the progress so far.
The Cairns. Picture: Tom O'Brien

Dig director’s mid-season summary of work so far

Well, folks we’ve reached the mid-point in this season’s excavations at The Cairns, and so I thought, I’d sum up the progress so far.

A reminder that we had three key areas we wanted to focus on as we entered the field season this year. These were:

  • The broch – where we wanted to explore more of the interior and its floor deposits than ever before.
  • Examine Structure O and establish the fuller outline of this broch-period village building.
  • Excavate the substantial broch-period midden immediately outside the broch and understand the context of the remarkable ‘Elder’ assemblage and its relationship to this midden.
  • Along the way it has been both expedient and very, very interesting to open a “fourth front” in the vicinity of building remains that are apparently associated with Late Iron Age building, Structure E.

Okay. Let’s take each of these areas one at a time.

The broch

The interior space of The Cairns broch.

Inside the broch, the focus of the team, led by area supervisor Rick, has been on two areas where we’ve previously undertaken less work than in other zones of the broch. These are the so-called North and Central Rooms, respectively.

Early on, we’ve established that the Central Room is indeed a corridor space that permitted/guided access into both the North and West Rooms (a “co-axial” passageway). It’s nice to confirm this and it is effectively the last piece of the puzzle in unravelling the nature of how the household moved around the broch from space-to-space, room-to-room, 2,000 years ago.

It seems that the Central Room was not just intended for access, however, as the volume of artefacts and animal bone, as well as stone tools, seems to suggest that some activities were taking place there also.

Some of the material here may well be the result of waste that was redeposited from processes under way in other rooms – a way of filling up the inevitable erosion and ruts in what would have been a high-traffic area with lots of Iron Age footfall.

The size and condition of some of the pottery fragments, however, suggests that at least some areas of the quite wide Central Room were not subject to trampling. So, our modern perception of corridor spaces, as merely transitional space – as non-places as Marc Augé would put it – is misleading and does not encompass what a passageway might have involved and what it might have meant to Iron Age sensibilities.

Working in the North Room of the broch. (ORCA)
Tom and Sara working in the North Room of the broch. (ORCA)

In the adjacent, much more “roomy”, North Room, work has also proceeded at pace.

In the West corner of this large room arc, we’ve established yet further signs of internal subdivision and it looks like there was a semi-separate quality to the space there, with a recognisably different character of occupation deposits from the rest of the North Room.

Of course, this is also where the massive whalebone rib came from in week one of the excavation and judging by its place in the sequence this looks very like it was part of the elaborate “structured abandonment” process under way inside the broch around AD200.

One of the larger pieces of Fin whalebone previously found in The Cairns broch. (Andrew Hollingrake)
One of the larger pieces of Fin whalebone previously found in The Cairns broch. (Andrew Hollingrake)

Many whalebone fragments – largely fin whale – were cut up and distributed around the broch, along with many other caches and deposits of artefacts and animal remains, at the termination of the broch.

The presence of the rib here, then, potentially allows us to establish the upper occupation in the North Room as contemporary with the abandonment-period activities elsewhere in the broch. That may sound like an obvious conclusion, however we have previously found several instances of the rooms in the broch possessing different histories of deposition and possibly going out of use at different times from each other.

So, the strong possibility that the North Room was also involved in the overall process of abandonment allows us to synchronise the story of this room with the others.

I’m really looking forward to seeing what emerges from the North Room next as already it is producing stone tools and other whalebone items.

The stairs leading into the ‘well’ at The Cairns broch. (ORCA)
The stairs leading into the ‘well’ at The Cairns broch. (ORCA)

Of course, this is also the room that hosts the entrance to our underground “well” and it will therefore be very interesting to see what unravelling the aboveground story of this room dies for our understanding of the context of that elaborate underground chamber. We’ll keep you posted!

Today, we also resumed work in the broch’s South-east Room and began excavating features in the clay floor. We’ll also keep you updated on what we find from here.

Structure O

Outside the broch's main entrance today, with the paved revetment area overlying Structure O in the foreground. (ORCA)
Outside the broch’s main entrance today, with the paved revetment area overlying Structure O in the foreground. (ORCA)

Over in Structure O – a village building of the broch-period – The Cairns has pulled off its familiar trick on us and gone and become more complex than we expected!

Sean and his team began the season excavating and recording the features that partially overly the building, with a view to recording and removing a late episode of paving so that we could note the full outline of Structure O beneath.

The paving, and its accompanying revetment wall, seem to be part of a short-lived, outdoor terrace on what would have been the mound of the earlier broch ruins.

The hearth-like feature in the paving over Structure O last week. (ORCA)
The hearth-like feature in the paving over Structure O last week. (ORCA)

At the centre of the paving, however, we have encountered an interesting feature. In appearance it is a little like a rough hearth, with some sense of edge-set stones providing a bounded setting. There’s some ashy, burnt material in attendance but not a lot, yet.

The feature seems to be, to some extent, semi-sunken and pit-like in nature. We must excavate this feature to understand it’s fuller relationship with the paving episode – is it contemporary with, or later than, the paving? Time will tell, but we will take time to fully record this enigmatic part of the site story.

Long experience has often shown that it is these somewhat-less-clear, quite ephemeral, episodes/events on site that, in hindsight, become quite important to unlocking a better, more subtle, sense of what the past community was doing. More news of this feature to follow…

Meanwhile, as reported in week one, the small amount of work that has taken place in the exposed area of the rubble that fills Structure O revealed that it contains a few interesting deposits of semi-articulated Associated Bone Groups (ABGs). These hint that the formal process of abandoning the village building was like that of the broch itself and gives us something to really look forward to when we reach the stage of fully excavating this rubble.

It’s nice to be able to look forward even to rubble removal as an exciting and enlightening process!

Broch ‘frontage’

The shell midden under excavation. (ORCA)
The shell midden under excavation. (ORCA)

Immediately outside the broch, at the broch frontage, Holly and her team’s mission was to expose as much of the shell-rich midden as possible by recording and removing large volumes of rubble so that we could see the midden more clearly.

Holly and Chloe excavating the shell midden outside the broch - the broch 'frontage' area. (ORCA)
Holly and Chloe excavating the shell midden outside the broch – the broch ‘frontage’ area. (ORCA)

Having achieved that and shown some interesting contextual relationships between things in this locale, they were ready to begin excavating and sampling the midden.

This will be achieved by running a long section through the width of the midden and simultaneously exposing the deposits continuously from the broch’s outer wall face to Structure O.

That way we can both explore the contents of this midden and assess the relationships across a varied and important set of buildings, features, and events.

From what we have seen this week, the midden is very full of shells and that’s also great news for area supervisor Holly, who is undertaking a PhD on marine molluscs at the UHI Archaeology Institute, with The Cairns being one of her key case studies.

As we had hoped, the midden also contains animal remains, including seal, deer, and fishbone so far. It also has artefacts – pottery and worked whalebone.

The Cairns 'Elder's' mandible - has another of her teeth turned up on site?
The Cairns ‘Elder’s’ mandible – has another of her teeth turned up on site?

Importantly, thus far, we can see discrete layers, or lenses, of deposition, horizontally banded within the midden, so we can unravel something of a sequence to the midden and how it accumulated through time.

One of the most exciting things to come from it so far, and just at the very end of last week, was a human tooth.

With its flattened cusps and quite wispy roots, and its proximity to the “Elder assemblage“, I would tentatively suggest that this is indeed one of our previously recovered, venerable old lady’s missing teeth!

It would have worked loose in its “post-depositional environment” and been “migrated” slightly by some past critter or another. It’s a reminder that this midden, at least it’s upper part, is very much part of the same series of events as the burial of the Elder jawbone and is close to the time of the end of the broch.

We shall see how far back this midden stretches into the broader period of the broch in the first and second Centuries BC/AD…

The extension

In our area at the south-east of the main trench, where we decided to explore the bitty remains of stonework that were visible just under the topsoil at the start of the season, things have come on leaps and bounds.

An array of well-built walls, cells and stone partitions have emerged from the hard work undertaken by Ole, Anthea, Deryck, Duncan, Iain, and Felix. These structures have every appearance of being well-preserved with substantial depth.

The fill of this multi-cellular structure – or possibly structures – includes some heavy rubble and it appears to have been deliberately back-filled, and swiftly so, if the voidy, largely soil-free nature of the rubble is anything to go by.

We have been working with the hypothesis that these cells are an integral part of nearby Structure E – a 7th Century AD building we excavated some years ago. The builders of Structure E truncated the remains of the broch ruins to establish a sound foundation for their new construction.

Excavating in the cellular area near Structure E today. (ORCA)
Excavating in the cellular area near Structure E today. (ORCA)

Towards the end of last week, however, we got an interesting surprise as a section of straight walling emerged – typically from under our control baulk, i.e., the edge of the excavated area – which threw that hypothesis into doubt.

The wall does not seem to fret into Structure E, but seems to demarcate the multi-cellular area as something in its own right – an independent building. We’ll need more time to prove this, but it seems possible that we’re looking at an entirely different building from Structure E.

If so, it’s one that seems to have been constructed later, thus becoming the latest Iron Age period building we know of prior to the arrival of the Norse on site.

Changing of the guard – thank you!

I’d like to recognise their efforts by saying a big thank-you to all the team for the first half of the excavation and especially those who have now left us at this stage – the first UHI excavation fieldschool and regular, stalwart volunteers Anthea and Deryck.

We look forward to sharing our findings with the next group of UHI fieldschool students and with newly arriving volunteers.

We’ll also continue to share our findings with you in this regular daily blog too.

So watch this space…

Martin Carruthers
Site Director

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