Structure Eight

Structure Eight.

At over 18 metres long by 9.5 metres wide, Structure Eight is the largest example of piered architecture found on site to date.

Ness of Brodgar Trench P: Structure Eight.Unlike Structure Five, which was extended over time, Eight’s monumental proportions were planned from the outset, possibly to incorporate the remains of two earlier buildings into its fabric.

In its heyday Structure Eight must have been an incredible sight.

Its interior was compartmentalised by double piers and featured at least four large stone hearths. On excavation it not only contained the first evidence of stone-tile roofing but also “painted” walls and the building has consistently produced stunning examples of incised Neolithic art – including the 1925 “Brodgar Stone”.

Constructed around 3100BC, shortly after Structure One, Eight was raised on the remains of Structures Seventeen and Eighteen. However, as encountered in other Ness buildings, this led to serious subsidence problems.

Although it must have been recognised that Structure Eight’s poor foundations would affect its stability, little effort went into levelling its predecessors or preparing the site for rebuilding. Instead, the builders carefully and deliberately incorporated elements of Seventeen and Eighteen into their new construction.

A section of Structure Seventeen’s inner wall face, for example, remained visible in Structure Eight and its western pier reused in the new building.

The relationship between Structure Eight and its predecessors, Structures Seventeen and Eighteen.

The relationship between Structure Eight and its predecessors, Structures Seventeen and Eighteen.

The apparent lack of concern with longevity and structural integrity and the integration of elements of Seventeen and Eighteen implies that it was the site, and probably the earlier buildings, that were considered more significant.

Whatever the reasoning, Structure Eight’s shaky foundations resulted in two main phases of activity – pre- and post-collapse.

Phase One

Structure Eight Phase OneIn its primary phase the interior was divided by four sets of opposed piers projecting from the inner walls. These, and corner buttresses at the southern end, created a series of recesses along the sides, a large cell at the southern end and two small end cells flanking the narrow northern entrance.

Investigating how these spaces were used continues to be a goal of excavation. The small northern cells, for example, were paved suggesting a different role from their larger, unfloored neighbours.

Stone slabs embedded into the floor separated the side and southern recesses from the central area. One of these dividing slabs had two large, oval holes “cut” into its lower edge. Why? It’s not clear but their size perhaps allowed heat from the adjacent fireplaces circulate in the recess behind.

Jim Bright recording one of the perforated orthostats for a 3D model. (Jo Bourne)

Jim Bright recording one of the perforated orthostats for a 3D model of Structure Eight. (Jo Bourne)

As mentioned above, although Structure Eight was clay floored the side recesses were not, with rubble forming the base. In one instance the masonry of Structure Seventeen protrudes into the side chamber.

A similar situation was encountered in Structure Twelve leading to the suggestion that the recesses once housed raised platforms.

Evidence in Structure Twelve points to at least two of the recesses being used for cooking and/or heating food. Micromorphological analysis of the Structure Eight recess suggests a role involving unburnt peat as well as high-temperature burning [1].

Chemical analysis also recorded high levels of phosphorus in the recess – something also suggestive of peat storage [2]. Similar XRF[3] analysis in Structure Fourteen also suggests that peat may have been kept in a recess [2]. Peat must be dry to be used as fuel so, if it was being housed within the Structure Eight recess, the perforations would not only allow air to circulate but allow moisture to run out.

Excavation through an orthostatic perforation. (Jo Bourne)

Excavation through an orthostatic perforation. (Jo Bourne)

Unlike other Ness buildings, Structure Eight stands out as having a single entrance. There may have been a second in the south-eastern corner, but this area was completely levelled to allow the construction of Structure Ten around 2900BC. Given the way Eight was superimposed on the footprint of Structures Seventeen and Eighteen, it is possible that the hypothetical second doorway occupied the same space as Seventeen’s former entrance.

The many artefacts recovered include a large whale tooth, maceheads, polished stone axes and a single whalebone macehead. We also know that Arran pitchstone, imported to Orkney, was being worked within its walls.

Pitchstone is a volcanic glass, similar to obsidian, and its nearest source is the south-west Scotland. In Orkney it has only been found at the Ness and the Barnhouse Settlement, 400 metres to the east.

Painted walls

Structure Eight was the site of a number of excavation firsts for the Ness. It was, for example, the first building in which we encountered masonry that had been deliberately “painted”.

Vivid earthy colours of reds, browns and yellows had been applied to wall sections that had been derived from ochre, haematite and galena.

Some stone faces appear to have been completely covered in pigment while others showed evidence of designs paralleled by some of the incised rock art from the site.

Stone roof

Since Skara Brae’s discovery in the mid-19th century, the form of Neolithic roofing has been the subject of debate. It was long assumed that the roofs of Neolithic dwellings had to be made from perishable, organic material — whalebone or driftwood beams supporting a roof of turf, skins, seaweed or straw. 

Structure Eight was the first building at the Ness to shed some light on the matter, yielding clear evidence that it had a stone-tiled roof.

This was a layer of carefully trimmed rectangular slabs lying on top of the floor deposits in the northern end. Such was their number that they were originally thought to represent paving. But it soon became clear that we were looking at fallen roofing material!

The distribution of the tiles showed that their size decreased towards the centre of the building and were smaller at the end walls, suggesting the roof followed the curve of the structure. The internal piers that divided the interior may also have shortened the unsupported span of the roof frame, making a stone roof more stable because each section had less weight to support.

Large quantities of clay found among the tiles may have been used to seal and weatherproof the roof.

Although roof tiles were also found in the southern end, there was nowhere near the same quantity. This was the first hint of an event that ushered in the second phase of Structure Eight’s life – a phase that was nowhere near as grand as the first.

Phase Two

Structure Eight Phase TwoAround 3000-2900BC, the Structure Eight paid the price for its shoddy foundations. Subsidence saw sections slump as the midden and earlier structures it sat on settled. The southern end, lying on top of Structure Seventeen, fared worst and its section of the roof collapsed.

The northern end survived and remained in use, with a large post inserted to support the remnants of the roof. Inside, the remaining piers were extended inwards by adding orthostatic “boxes” to the ends and filling them with rubble (which included decorated stone).

Shortly after the calamity, work to construct Structure Ten began. This saw the partial demolition of surviving sections of Structure Eight’s south end and the rubble cleared away. Activity continued in this area, however, and centred around the large southernmost hearth.

The volume of ash and burnt material encountered in the area suggests burning on a scale that is unlikely to have taken place indoors.

Whatever was going on, it is clear that activities at either end of the building were markedly different. In the north section, excavation revealed a large quantity of artefacts such as stone spatulate tools, animal bones and polished quartz, many of which had been deliberately placed in the side recesses and near the remaining piers.

Most lay directly beneath the layer of tiles littering the floor, meaning their deposition was shortly before the collapse or deliberate demolition of the remaining roof section.

A cobblestone tool cache revealed during excavation of one of the second phase pier extensions in 2012.

How long the remains of Structure Eight were used after the construction of Structure Ten is presently not clear. However, it would seem that the northern half of Structure Eight was still being used during the occupation of at least the primary phase of Structure Ten.

 

 

Notes

  • [1] McKenzie, J. (2020) Micromorphology. In Card, N., Edmonds, M. and Mitchell, A. (eds) The Ness of Brodgar: As it Stands. The Orcadian: Kirkwall.
  • [2] Pike, S. and Shinsato, L. (2020) Geochemical analysis of the floors from Structure 14 using a portable XRF. In Card, N., Edmonds, M. and Mitchell, A. (eds) The Ness of Brodgar: As it Stands. The Orcadian: Kirkwall.
  • [3] X-ray fluorescence. An XRF spectrometer is an instrument used for on-site chemical analysis of rocks, minerals, sediments and fluids.
Structure Eight: Excavation over Time