Monday, March 14, 2011

Excavations at Banks Chambered Tomb, South Ronaldsay, Orkney

A team of archaeologists from the Orkney Research Centre for Archaeology (ORCA) recently undertook a rescue excavation on a newly discovered Neolithic chambered tomb at Banks, on the island of South Ronaldsay, Orkney.

The tomb is located on the southern tip of the island overlooking the Pentland Firth, approximately 1.8 kilometres from the Tomb of the Eagles at Isbister. Whilst this new monument sits well within the rich archaeological heritage of the islands, the very fact that new examples are still being discovered underlines the remarkable prominence of this type of Neolithic burial monument.

The site is important as it offers a rare opportunity to investigate the life history of a tomb, from construction to decommissioning, using modern archaeological techniques. Antiquarian investigations usually beat modern-day archaeologists to these sites in Orkney so their apparent absence at Banks was promising. This new exciting discovery once again puts the Neolithic spotlight on the islands.

It is a surprise to many that any large mound in Orkney is not suspected to represent some form of prehistoric monument, but this was the case at Banks. The former elongated mound situated to the south of the farmhouse is clearly visible on old aerial photographs. However, it was unusually shaped, being long and ridge-like (c. 80 metres long and about 2 metres high), and was never thought to contain any structural archaeology. The tomb was only discovered recently during development works around a nearby farmhouse. The large slabs that started to emerge in the top of the mound soon raised suspicions and initial explorations revealed a revetment wall to the north and the presence of internal chambers. The body of the mound had unfortunately been destroyed but the structural heart of the monument had survived. The cells were flooded with water and the eastern cell clearly contained a human skull, and so a rescue excavation was organised, funded by Orkney Islands Council and Historic Scotland.

The mound was originally elongated, and the builders appear to have utilised a natural feature evidenced by a sharp rise in the bedrock below. This feature may have formed a significant place in the Neolithic landscape perhaps already imbued with stories and meaning. The use of natural places for monumental architecture and other activities is well attested, although evidence for this practice is less well-known in Orkney. Perhaps the most famous example is the Dwarfie Stane in Hoy, the only rock-cut tomb in the UK, where the cells were carved inside a glacial boulder.

The Banks tomb is unusual in that it is partly subterranean. The central chamber, cells and entrance passage were constructed within a quarry. Rather than just stripping the area prior to construction, the Neolithic builders commenced with the task of quarrying. The central chamber (c. 4 metres long and 0.75 metres wide) is aligned east to west with an entranceway leading off to the north, with two larger cells at either end, a single cell to the north and two cells to the south. The sides of the cells are formed from a series of piers extending out from the bedrock face that forms the rear walls. The southwest cell, opposite the entrance passage, has an upper shelf similar to those above the end stalls in the Tomb of the Eagles. The west cell has unfortunately been severely disturbed.

The cells are capped with large water-worn slabs that rest on the upper level of the bedrock with the sides are supported by the stone built piers and walls. The walls are constructed from various quarried stones, apparently from different sources that do not appear to derive from the construction quarry itself. The rounded slabs and blocks, often used as corner stones, and the water-worn capstones probably came from the nearby beach to the west. The use of water-worn material seems to go beyond simple practical requirements. Although the excavations are not complete, it seems that water-worn material was used at key stages in the life of the tomb: in construction and closing off. It is interesting that Chris Fowler and Vicky Cummings have suggested an association between water, death and change in the Neolithic. In this manner water may have been referenced in certain places of transformation.

The main burial deposits were not reached during the excavation but a glimpse of the closing-off process was afforded by investigation of the entrance passage, central chamber, and north and east cells. The cells and chamber were filled with placed slabs to a level c. 0.6 metres below the roof. There was then a pause in the closing process, evidenced by the presence of otter sprait above the slabs, perhaps for a final closing ceremony or act. This closing ceremony consisted of the placement of predominantly skull fragments, but also pelvis and femur, within the north and east cells. The initial assessment of the assemblage has indicated that the bones are in good condition with a minimum number of seven individuals from the cells. These bones were certainly curated outside the tomb while the slabs were put in, but where and for how long remains a puzzle. It is tempting to suggest that the whole skull placed just inside the entrance of the east cell was the final closing act. As an archaeologist this discovery was certainly an emotional experience: to be literally faced with that moment in time, staring back at you.

The central chamber and cell doors were then sealed with silty clay material and stony clay was used to block the entrance. A smooth water-worn stone was placed just inside in the entrance passage before it was finally sealed off. Water quickly filled the tomb to around the level of the bone assemblage. Remarkably, the tomb lay undisturbed until the recent development at Banks.

The monument could be classified as a Maes Howe type chambered tomb. These, according to Davidson and Henshall, typically have a narrow entrance passage which leads to a central chamber with side cells constructed into the walls. This contrasts with the tripartite and stalled cairns of the Orkney-Cromarty Group that have a broad and often long central chamber that is subdivided into compartments with upright slabs that protrude into the chamber. The more varied Bookan type, some with squared internal cells, complicates matters further. Interestingly, most of the Bookan type tombs are semi- or completely subterranean. In a recent review of Orcadian chambered tombs, Nick Card suggests that while such classifications can be a useful tool, the wide variety of monuments demonstrates that sites should be assessed on their own basis before attempting to construct typological and/or evolutionary models. Clearly, the Neolithic community at Banks were drawing on a broad architectural and spiritual repertoire that was brought into focus at certain places and reworked over time.

It is not possible to comment on the use of the Banks tomb at this stage as the main burial deposits, if they exist, were not reached. The nearest comparison is the Tomb of the Eagles where hundreds of individuals were communally buried. Here, John Hedges noted that the bones were arranged in distinct piles in the central chamber and cells as if they had been frequently moved or sorted. Some archaeologists, such as John Barrett, have argued that it was the construction of tombs and the subsequent manipulation of the remains of the dead by a select few that created social relations and power structures in the Neolithic. Perhaps the burial deposits at Banks will help us add to these interesting debates.

The research potential for further work is high. The opportunity to investigate the backfill and closing off sequence of an undisturbed Neolithic tomb is very rare. Indeed, the waterlogged conditions within the tomb, which appear to have remained stable until recently, provide the potential for rich organic remains to survive and good preservation conditions for the human bone assemblage. ORCA aims to return to the tomb this year to continue the excavation. Investigations at Banks chambered tomb offer a rare opportunity to get a step closer to understanding Neolithic funerary practice in Orkney at an internationally important site.

The involvement of 360 Production in the project from the outset, who are filming the new Digging for Britain series, also offered us the opportunity to try to present the site in a different way to the public. It was decided to film a daily site diary and post this on Youtube the following day. Whilst the initial intention was to promote the site for the upcoming series, it provides an interesting insight into the process of archaeology with the decisions and experience of working onsite, even the numerous gales! We hope this innovative contribution to the presentation and accessibility of archaeology will provide a new challenge to archaeological fieldwork practice.

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