A day of site-wide revelations…
Dig Diary – Tuesday, August 4, 2020
Wednesday, August 4, 2011, was a day of revelations in Trench P.
Working in Structure Fourteen it became clear that the archaeology was more than a collection of ephemeral walls post-dating most of the other buildings on site. Instead, it was another piered building similar to Structures One, Eight and Twelve and contemporary with them.
From initially wispy walls, Structure Fourteen could now be seen to be a symmetrical building, around nine metres metres wide and eleven metres long, with an entrance at its eastern end and one on its southern side.
Although some of its walls had been badly robbed out, we could now see other architectural features it shared with One, Eight and Twelve, apart from the use of piers and extremely fine angular masonry. The main wall consisted of two separate elements – a double-faced inner wall, with an outer revetting wall, and a midden core between the two.
Jumping forwards to 2014 (weekends again) the bone deposits in Structure Ten’s 1.81m wide entrance were confirmed to be made up of entirely cattle toe bones. Marking the entrance was a massive threshold slab, which could now be seen to have been carefully trimmed and dressed round one side.
In Structure Eleven – a feature represented by a curving wall between Structures One and Eight – the discovery of a hearth added to the 2014 mystery of what the building represented and how it fitted into the Trench P timeline.
Now, with the benefit of six years additional excavation, we know Structure Eleven was constructed around the same time Structure One was reduced in size, incorporated the south-western corner of Structure Eight into its fabric and may be part of Structure Nineteen to the north.
Trench T continued to throw up surprises on this day five years ago.
A large, broken orthostat had turned up at the bottom of the trench a few days previously and was followed, on August 4, 2015, by the remnants of a well-made, by robbed-out, wall. Because the wall lined up nicely with the orthostat, to which it was perpendicular, it seemed we may be looking at the remains of orthostatic divisions within the building we now know to be Structure Twenty-Seven.
The use of upright stone slabs to divide up a building is also seen in Trench J’s Structure Five and finds parallels in the construction of stalled chambered cairns in Orkney, such as the Blackhammer and Midhowe cairns, in Rousay.
The size of the orthostat was one of the early indications that we were looking at the remains of a large building. We now know Structure Twenty-Seven was approximately 17 metres long by 11 metres wide, with c2.4 metre thick walls.
Evidence of roof tiles in Trench T the day before was followed by more in Structure One, suggesting it to, in its primary phase, had a stone-tiled roof.
The weather in 2016 was not playing ball, but among the finds four years ago was another “chequerboard” incised stone.
This example was one of a number recovered from Structure Eleven and which had been built into the walls – and therefore not visible – as the building was being constructed.
In 2017, more of Structure Five was being uncovered daily.
It turned out to be badly stone robbed but it was still possible to trace its outline, in particular its slightly waisted form and orthostatic radials in common with early buildings, such as the Knap of Howar, Smerquoy (in St Ola) and the Braes of Ha’breck (in Wyre).
Outside Structure Five, the outside wall face of the “Great Wall of Brodgar” had been exposed, but it too had been extensively plundered for stone in prehistory.
The “Great Wall” respected Structure Five, gently curving round it, and both constructions sat directly on top of the natural boulder clay, making stratigraphic separation impossible. It raised the question, however, whether the wall was much earlier in the history of the site than we had previously thought.
And there, because August 4 fell on the weekends in 2018 and 2019, we end today’s trip through memory lane.
See you all tomorrow.