Excavation Neolithic Ness of Brodgar

Seven weeks at the Ness of Brodgar – a summary of the 2021 excavation

Seven weeks of excavation ended at the Ness of Brodgar on Friday, August 13, with the Neolithic structures now back under its protective covers.
Surrounded by a sea of tyres - drone shot of Structure Twelve. (Jim Rylatt)
Surrounded by a sea of tyres – drone shot of Structure Twelve. (Jim Rylatt)

Seven weeks of excavation ended at the Ness of Brodgar on Friday, August 13, with the Neolithic structures now back under their protective covers.

The project, run by the Ness of Brodgar Trust in conjunction with the University of the Highlands and Islands Archaeology Institute, has been investigating a complex of buildings in the Heart of Neolithic Orkney World Heritage Site since 2006.

The 2021 excavation – the first since 2019, due to the pandemic – began on June 28, but on a much-reduced scale to previous seasons.

The trenches at the Ness of Brodgar excavation site.

With a smaller team than usual, only Structures Ten and Twelve were uncovered, along with Trench J, which contains the remains of Structures Five and Thirty-Two and the northern boundary wall (aka “the Great Wall of Brodgar”).

Dating to around 3300BC, Structure Five is the oldest excavated building on site, built some four centuries before Structure Ten. It is also the largest Early Neolithic, non-funerary building in Orkney.

Work this year, however, has showed its history is much more complex than originally thought.

It had always been assumed that the building’s northern end was primary and that the southern end was perhaps a later, tacked-on addition. A trench extension, however, revealed archaeology suggesting there is a lot more to the story of Structure Five.

The curve of its newly exposed western wall, for example, suggests its size may have been underestimated. Originally suspected to measure over 16 metres long, extrapolating from the curve it is now likely that Structure Five is much bigger, its southern end lying several metres beyond the trench edge.

Structure Five with the ‘Great Wall of Brodgar’ in the foreground. (Sigurd Towrie)
The western walls of Structure Five uncovered. (Sigurd Towrie)

It also seems that the building’s primary entrance was on the north-western side but was sealed off in antiquity, replaced by a series of doorways in the south-eastern wall. An earlier phase of Structure Five may also have had an outer buttress like that encountered during the excavation of the Early Neolithic structure at the Braes of Ha’Breck, in the Orkney island of Wyre.

To further complicate matters, another set of wall lines running off from Five could relate to another, earlier, structure. These features will need further excavation before any firm conclusions can be drawn.

Another intriguing discovery related to the building’s position on the ground. Structure Five, unlike the later buildings on site, was constructed on natural glacial till – the original ground surface 5,000 years ago. The difference in height of the glacial till outside and inside the building revealed that the building’s interior was below ground level.

This probably accounts for the clay sealing found on the lower courses of the walls – a feature also encountered at the Early Neolithic settlement site at Smerquoy, at the base of Wideford Hill. Without the clay barrier, Structure Five would have filled with water in wet weather! This may also go some way to explain the insertion of what appears to be a large drain and the northern, lower, end of the building.

A sherd of the round-bottomed, Early Neolithic pottery found in Structure Five. (Sigurd Towrie)

Excavation of the floor levels in the southern half of Structure Five revealed fine, hard-fired pottery which was clearly not the flat-based Grooved Ware, which appeared on the scene around 3200BC.

The sherds were part of a round-based bowl with a notably curved profile and which was a mere 11mm thick. The exterior had been carefully smoothed leaving fine, roughly-horizontal striation marks.

Although round-based bowls preceded the appearance of Grooved Ware, the advent of Grooved Ware does not constitute a clean break with the previous ceramic tradition – both types of vessel overlapped with each other in the archaeological record.

What the discovery does confirm is the early date ascribed to Structure Five based on its architecture and position within the site.

Chris and Ceiridwen excavation floor deposits inside Structure Thirty-Two. (Sigurd Towrie)
Chris and Ceiridwen excavation floor deposits inside Structure Thirty-Two. (Sigurd Towrie)

Staying in Trench J, excavation confirmed that the later Structure Thirty-Two, built on top of the rubble of Structure Five, incorporated elements of its predecessor into its construction. The building, which was found to contain several ashy layers also produced an incised decorated stone from its floor level.

Structure Twelve, looking north. (Sigurd Towrie)

If there was one find that drew attention in 2021, it was the survival of Neolithic wood at the base of two rectangular post-holes inside Structure Twelve.

Large, roof-supporting post-hole in the south-eastern corner of Structure Twelve. (Sigurd Towrie)

Twelve is no stranger to post-holes. A series of four (perhaps five) were found to run along the northern section of the interior – perhaps, given their size, to hold a screen or partition separating two areas of the building.

In addition, two larger postholes were excavated – one in the south-east and western recesses. The large posts these held seem to have been inserted into the structure prior to its collapse in an effort to hold the roof up.

Unfortunately for the Neolithic builders their efforts were in vain and when Twelve’s southern wall collapsed it brought the roof with it.

But the Neolithic wood came from an area east of Structure Twelve’s southern hearth. The discovery was in the same area as robbed-out orthostats close to the building’s grand eastern entrance. These once formed the southern side of an entrance passage into the building, separating it into two distinct halves.

The two wood-filled post-holes were rectangular and, at around 5cm and 10cm wide, were noticeably bigger than the stake-holes that represent cooking arrangements found throughout the building.

The two postholes with surviving wood within (the darker areas) from Structure Twelve at the Ness of Brodgar. (Sigurd Towrie)
The two postholes with surviving wood within (the darker areas) from Structure Twelve at the Ness of Brodgar. (Sigurd Towrie)

It is thought they may represent a screen that replaced the line of entrance passage orthostats in the second phase of Structure Twelve’s life.

Dr Jo McKenzie recovering samples of the wood. (Sigurd Towrie)
Dr Jo McKenzie recovering samples of the wood. (Sigurd Towrie)

Due to the acidic nature of the soil, organic preservation at the Ness of Brodgar is poor. In this case, the wood was not in good condition, but its survival seems to relate to a slight dip in the floor which allowed water to pool and thus preserve the material.

The job of recovering the ancient wood fell to micromorphologist Dr Jo McKenzie, who successfully, and expertly, secured both for further analysis.

The Ness of Brodgar site has more than its fair share of pottery sherds – well over 90,000 have been recovered so far. But outside Structure Twelve’s blocked north-western entrance were huge pieces from a gigantic, decorated vessel that stood approximately half-a-metre high and with a diameter the same! Whatever it held there is no doubt that it was a considerable volume!

The pot’s deposition outside a deliberately blocked entrance is something encountered at the Ness before and was probably deliberate.

Chris excavating one of the huge pottery slabs from outside Structure Twelve’s blocked north-western entrance. (Sigurd Towrie)

Outside Structure Twelve’s shoddy northern annex, UHI Archaeology Institute alumni Calum Hall was tasked with unpicking the construction sequence of the later addition.

Calum unpicking the stratigraphy of St12’s northern annex. (Sigurd Towrie)

The annex was added to Structure Twelve during its second main phase of use. The primary phase ended when the south wall and roof collapsed. Rather than abandon the stricken building, it was decided to reconstruct it. But these repairs were not exactly high quality.

At the same time, the north-western and southern entrances were blocked and a new entrance inserted into the north wall, leading into the new annex.

It seems, based on current evidence, that the annex’s addition was as inglorious as its architecture. Rather than clear away a huge, bulbous mound of midden that sat at Structure Twelve’s north end, the Neolithic construction team simply cut into the midden and built the annex walls up against it.

While this was undoubtedly a quick solution, given their stonemasonry skills, they must have known it was shoddy build. Was it meant to be temporary? Perhaps a stop-gap until a more permanent solution could be found? Or were they not overly-concerned about how the new addition looked?

One thing is for sure, the fact it survived to its current height is something that continues to amaze and prompted site director Nick Card to comment: “How that has managed to stay standing for over 5,000 years is beyond me.”

The earlier buildings at the Ness were also in the spotlight this season. In Structure Twelve, elements of its predecessor, Structure Twenty-Eight appeared at the bottom of one of the large, roof-supporting posts mentioned above.

Meanwhile, unlike the trenches beside Structures Five and Twelve, at Structure Ten the emphasis was not on expanding but going deeper. Here Professor Mark Edmonds was investigating Structure Twenty, visible elements of which lie beneath the Structure Ten’s entrance forecourt.

Mark’s sondage into Structure Twenty. The outer and inner wall faces are shown as dashed lines. At the top of the picture, also represented by a dashed line is the top of the protruding orthostatic divider. (Sigurd Towrie)

At present Structure Twenty consists of a wall line and an orthostat partly built into Ten’s internal wall face. The rest of the building is obscured by the later construction on top, so Prof Edmonds opened a small sondage in the hope of reaching the Structure Twenty floor deposits and securing dating material.

The inner face of a section of Twenty was revealed, along with a large orthostat jutting from it. This stone slab was probably one of a number used to divide up Structure Twenty’s interior. The later Ness buildings, such as Structures Eight and Twelve, used stone piers to create different areas while earlier structures, such as Five, used stone slabs.

By the end of his exploration, Prof Edmonds had successfully a sizeable quantity of charcoal which should allow the building to be radiocarbon dated.

Sigurd lifting the latest in a large number of hammerstones found in Structure Ten, for possible analysis by the Chemarch project. (Dr Aimee Little)

In Structure Ten itself another example of “painted” stone appeared – with what appears to be vivid red pigment surviving on an orthostat in the building’s northern end. Beside the orthostat was a chunk of red sandstone which may have been the source of the pigment used.

Among the distinguished visitors this summer was Dr Aimee Little, from York University. Dr Little is one of the principal leads of the Chemarch project – an international initiative focusing on archaeological chemistry, biomolecular archaeology and archaeometry.

One of the areas Chemarch is looking at is the function of stone tools – in particular whether residues on these tools can be analysed and give us a better idea of how they were used. To this end, a selection of suitable artefacts from the Ness was shortlisted to progress the project.

For more information on the ongoing Ness of Brodgar project, see www.nessofbrodgar.co.uk