First encountered in 2015, Structure Twenty-Seven lay beneath tonnes of deposited ash and domestic refuse in Trench T.
The excavation of this midden mound had begun in 2013 and, at first, it was thought to be nothing more than a monumental pile of rubbish – a highly visible symbol of conspicuous Neolithic consumption. In 2014, however, the stump of an apparent standing stone at the foot of the mound suggested there might be more to it. The mound was clearly covering something.
Structural remains were uncovered in 2015 and we now know Structure Twenty-Seven was a large sub-rectangular building built directly on the natural boulder clay.
As work progressed the sheer scale of the building was revealed.
Although it has yet to be fully exposed, Structure Twenty-Seven’s exterior is approximately 17 metres long by 11 metres wide, with c2.4 metre thick walls. Despite extensive stone-robbing, it is clear that great care and skill went into both its interior and exterior with some of the finest stonework seen at the Ness.
Given its position beneath a five-metre deep midden mound, and because it stands on the natural land surface, we had thought Structure Twenty-Seven might pre-date many of the other buildings on site. But its stepped foundations and high-quality stonework are very reminiscent of Structure Ten, the last major building constructed, so Structure Twenty-Seven may not be as early as once thought.
At present we have no dating evidence for the construction or demolition of Structure Twenty-Seven so its age and relationship with the rest of the site remains unclear.
From its first appearance there was no doubt that Structure Twenty-Seven was beautifully built — its exquisite masonry was enhanced by pick-dressing in places on its external wall face, and great care (and effort) had gone into cladding the interior walls.
Massive rectangular stone slabs, up to 4.55m in length, had been carefully set on edge and defined the interior space. Two of these slabs were placed end-to-end along the side walls and another along the south-west end wall.
The scale of these prone slabs is only matched by the large megaliths incorporated into Maeshowe and weathering noted on the exposed upper edges has raised the possibility they may have originally been standing stones.
Inserted behind and supported by these prone slabs, and flush against the interior wall, were a series of upright orthostats that clad and covered the less-than-perfect internal wall faces, producing what must have been a stunning and unique internal appearance to mirror the exquisite external finish.
Orthostatic slabs set partially into the walls created two “stalls” at each side of the interior. One of these orthostats was decorated with the same incised rectilinear designs found elsewhere on site. The excavators had previously noted the stone had unusual, but faint, markings on its surface.
Closer examination confirmed many incised lines, some forming chevrons and other geometric motifs as well as some probable “drag marks” relating to its quarrying and transportation. The presence of these geometric designs, some on the hidden back edge of the orthostat, would also imply that the building is later than we originally thought.
It was also clear that an inner edge had a rounded profile. These discoveries strongly suggested the massive slab had been used before, possibly in a different building, before its incorporation into Structure Twenty-Seven.
The presence of slates inside the building, together with the thickness of the walls, suggests Structure Twenty-Seven had the same slate-roofing as encountered elsewhere on the Ness.
Although elements of Structure Twenty-Seven’s impressive architecture have become clearer, the question of its role has not. Is it an Orcadian equivalent of a Neolithic timber hall recreated in stone? Or could it be like a structure encountered at the base of the Howe site, in Stromness, which was excavated in the early 1980s and interpreted (questionably?) as a stalled tomb? Or something totally different? Only more excavation can reveal its secrets, especially as we start to uncover its floor deposits and features that are so tantalisingly close.
What is beyond doubt is that after going out of use, Structure Twenty-Seven was dismantled and the stone forming the bulk of its fabric taken away. It was then gradually, and deliberately, covered with refuse and ash.
The discovery of large spreads of animal bone suggests this final demolition represents a more formal decommissioning that was accompanied by feasting — perhaps like that previously encountered at Structure Ten.