By Sigurd Towrie
Story dated: August 29, 2006

As another season’s work draws to a close, the Stenness side of the Ness of Brodgar continues to throw up archaeological surprises – including two pieces of iconic Neolithic art.

Investigating earlier geophysics scans of a field between Lochview and Brodgar Farm, a trench has revealed the remains of what may be a chambered tomb. And if it is, it could be the “missing link” between the two styles of Stone Age cairn found in Orkney.

When it comes to tombs, the early Neolithic period is characterised by stalled cairns – structures, such as Unstan in Stenness, which are divided into cells, or stalls, by large upright stones. Towards the end of the period, these were superseded by Maeshowe-type structures – circular with side chambers.

The Brodgar building appears to show characteristics of both. It was a large oval structure but was subdivided into radial chambers – similar to those found inside the Crantit cairn in 1998.

But the surprises didn't stop there.

Outside, the structure appears to have been surrounded by a large stone wall, perhaps reflecting the Barnhouse settlement’s Structure Eight - a massive hall-like structure, seven metres square and surrounded by an enclosing circular wall.

Overseeing the excavation was Nick Card, Orkney Archaeological Trust’s project manager.

“Last year we found a section of curved wall face within a mass of rubble,” he said. “This year we expanded the trench expecting to find the interior of a structure, but instead, we found another concentric wall.”

“This wall was part of an oval structure, seven to eight metres in length, and four to five metres across, with a entrance facing the south east. Inside, the structure was divided by stone uprights to form radial compartments.”

The purpose of the structure is unclear, as it appears to show elements of both ritual and domestic architecture.

Nick added: “Although it could be a house, looking at its scale it is more likely that we have something else. If it’s a chambered tomb it doesn't look like anything we've got anywhere else. We have a definite circular arrangement of space, but incorporating the stalled compartments found in the rectangular stalled cairns.”

The external wall may have been added at a later date, with the space between it and the structure filled in to create a wide stone platform, similar to that seen at Quoyness in Sanday. This, suggests Nick, could have been a cosmetic addition to further “monumentalise” the structure. Perhaps in its earliest phase the structure was a house, that later took on some other significance - a memorial for the community's ancestors for example.

A later drain also appears to have been added to the structure’s north-east wall, which meant a section of the exterior walling had to be removed.

In addition, it is also possible that the wall extends out further than the boundaries of the structure. Although further excavation will be required to be certain, the geophysics scans suggest the wall could extend right out across the Ness, towards the Stenness loch.

At the start of this week, the excavators were still working down through the rubble that covered the earliest phase of the structure, but its outline was clearly apparent.

“We’ve probably got anything up to half a metre to go through before we get down to floor level but we can see, for example, that the entrance features are identical to the Knowes of Trotty house we excavated earlier in the year.”

The date of the structure, and how it fitted into the Neolithic settlement on the Ness, remains unclear at present. However, the building does appear to have been altered over time, with considerable secondary activity surrounding it.

Probably dating from the early Bronze Age, by which time the structure was probably ruinous, this includes a number of exterior stone features.

One of these later additions was a triangular stone cist, cut into the rubble covering the earlier structure. This cist produced two small pieces of stone incised with the same repeated lozenge/chevron design as appears on a large stone found in the same field back in 1925.

The 1925 stone, which was found in one of three cists in the field, features eight bands of lozenge decoration – a design common at a number of megalithic sites, in Orkney and beyond.

Is the design a mere artistic expression, or was there another, more symbolic reason? The repeated lozenge, for example. Is it just a pretty pattern? Or, as some would have it, a geometrical representation of the positions of the solstice sunrise and sunsets?

Do the incised triangular shapes have a deeper meaning, or are they merely artistic representations of a pattern found on countless Orkney shorelines – that of weatherbeaten bedrock?

Although the debate on the symbolism will inevitably continue, the latest patterned stones once again highlight apparent connections between Orkney and the Boyne Valley in Ireland – one of the richest surviving repositories of Megalithic art.

Other finds from this year’s dig included a cache of flints and a number of polished stone axes.

The excavation was supported by Orkney College, Orkney Archaeological Trust, Historic Scotland and Orkney Islands Council.