Martin Carruthers, Site Director sums up last week by writing….Friday was open day and that’s always a cheerful, fun experience, with so many people of different ages and backgrounds turning up and enjoying a visual feast of archaeology.
Prior to all the visitors arriving, we finished removing the rubble from the final segment of the broch- and we all enjoyed finally seeing the western inner wall face of the broch revealed, especially Becky and her team.
The wall is very impressively monumental and very skilfully constructed as in the other parts of the broch. The broch suddenly has a more open, and obviously complete, feel to it.
Interestingly, the numerous uprights and partitions seen across the eastern half of the broch interior are largely absent from the western side as far as we can see.
This is perhaps to be expected in hindsight when one looks at a number of plans of earlier excavations of brochs in the Northern Isles, and Caithness.
These often show almost crowded uprights (orthostats) clustered around the side of the broch possessing the entrance but the area opposite is frequently quieter with much larger less differentiated space(s).
The other fascinating aspect is the presence of items in the lower rubble that we are now working down by hand. These include stone tools and animal bones. In one case, a really large piece of whale bone rib emerged.
As in other areas of the broch infill the rubble itself also seems to be the focus of some interesting deposition. We’ll keep posting some images of the broch interior as we remove more of the lower in-fills reveal more of the beautiful walling.
Elsewhere on site, the pottery vessel that has been found in Trench Q continues to develop with an apparently in situ pot lid present as well!
The souterrain looks especially beautiful with its main roof slabs now exposed and we can even begin to work out the construction sequence of the roof slabs as their overlap shows which ones were set up first, and which came after.
It looks as though the builders began at the southern end (where we previously found that they had installed a small stone setting encircling an arrangement of deposited rotary querns), and moved north as work progressed.
In Trench M, the furnace has now been completely lifted for post-excavation assessment, and it means we can carry on working through the rubble in the metalworking building, on which the furnace had been perched.
This week is final week and if you were unable to get down during the open day you’re still very welcome to come and see the site. We’ll be beginning to put the site to bed from Wednesday afternoon onwards so come out before that if you can.
Rounding up the previous weeks work, Martin continues…..
In the broch, Becky and her team have made great progress with the deposits inside the south-eastern “room”.They’ve revealed a lovely organic, carbon-rich layer. This is, without doubt, the uppermost occupation layer of the broch in this sector and it is a very greasy, black soil, full of charred cereal grains, burnt bone and all sorts of environmental evidence and fragments of artefacts.
An antiquary of the 19th or early 20th century would no doubt have used their favourite word for it – unctuous.
It’s very likely made up of degraded and compacted straw for flooring and bedding, as well as the thousands of little organic items trapped in it. The presence of these deposits is very good news as it means that, just as in the north-eastern sector excavated last year, we have lots of very well-preserved evidence for the actual use of the broch.
The other very good news is that we’ve had a selective peek under this black deposit and, again just like the north-eastern sector, there appears to be clean orange clay underneath. This is probably a formally laid down beaten-earth floor, on which the black unctuous matter was developing through the human use of the broch interior.
Hopefully, just as in the north-eastern sector, there will be several layers of this alternate black occupation material on top of clean clay descending down through the “deep history” of the broch’s use.
We are now excavating and sampling (100 per cent) of these floor deposits on a grid pattern, which means that we keep control of the spatial variations across the floors and this will tell us about what was going on across the different areas of the interior of the broch. We will find out much more over the next couple of weeks!
In Trench M, where the metalworking bronze working moulds and furnace have been found, things have also been progressing nicely.
One interesting aspect is that we now think the furnace is for iron-working, probably smelting, and so it looks as if both copper-alloying (i.e. bronze-working) and iron-working were going on at the same time in the same space.
This would be very similar to the smithy building at Minehowe, in Orkney’s East Mainland, and it’s probably happening at around the same period in the middle Iron Age. It’s therefore going to be interesting to see how similar, or different the situation in Trench M is to that amazing site.
The other fascinating thing learned about the Trench M metalworking is that it appears to be much longer-lived in this zone of the site than we previously knew.
We’re now finding a lot of metalworking waste from deposits dating to earlier than all the bronze moulds and the furnace, including bog ore, slag, and “hearth bottoms” (a kind of plano-convex, circular cake of industrial waste that builds up at the bottoms of furnaces.
All this evidence for a longer period of metalworking in Trench M is very useful in terms of understanding the nature and scale of craft-work and specialist production at The Cairns.
Questions like were the metalworkers members of the resident community at the site? Or were they itinerant, specialist craft-workers temporarily based at the site? These can, potentially, be sensibly approached with the new evidence we are acquiring.
The new trench – Trench Q – has also been moving forward. You may remember that this trench is in the area where we would expect a substantial segment of extramural village surrounding the broch to be.
Usefully, we are now starting to pick up fairly chunky, well-built walls in the western part of Trench Q.
These walls are double-faced, and therefore were free-standing, and this, together with their overall build quality, is perhaps indicative that we are indeed now starting to see the tops of walls belonging to village buildings of the settlement that goes with the broch.
We’ll continue to develop this area for the next two weeks and see what we come up with by way of proof of this. We’ll keep you posted.
In the souterrain – Structure F – things are also going well.
Holly, Beth and the “souterrain squad” (as they wish to be known!) have revealed details of the roofed portion of the souterrain passage and found that there are no fewer than three layers of substantial slabs covering the passage.
Each time a layer of slabs has been recorded and removed, we have seen that there are good rich soily deposits underneath and this will be very useful in terms of giving us material with which to potentially radiocarbon date the construction of the souterrain.
We anticipate that next week we’ll be able to reveal the main massive roof slabs of the souterrain and record them.
We will also soon be in a position to start carefully excavating the floor deposits inside, much in the manner of the broch using a sampling grid. That’s when the information about what was going on inside the souterrain will, hopefully, really begin to be collected!
As usual, all of this exciting work and newly acquired information wouldn’t be at all possible were it not for the conscientious and talented excavation team. So I’d like to express my gratitude to them for their hard work during the first two weeks of the season and I look forward to sharing more great discoveries over the next two!
Thanks to Sigurd Towrie and Orkneyjar