A three-week dig at Banks concluded in April, and saw the excavators recover a wealth of human remains as well as samples for DNA analysis.
It’s been high on the archaeological wish list for years: a prehistoric tomb containing human remains — remains that would allow modern archaeological techniques, such as DNA testing, to open a window into Stone Age life.
Back in 1998, hopes were high following the discovery of the Crantit cairn, just outside Kirkwall. But these were dashed when it became clear that the meagre remains inside had not stood the test of time.
But the discovery of the apparently undisturbed tomb at Banks last year — complete with visible human skulls — left the archaeologists with bated breath. They knew there were remains inside – they could see them. But the quantity and quality of preservation was uncertain.
So, a team of archaeologists from the Orkney Research Centre for Archaeology (ORCA) descended on the tomb last autumn and recovered the remains of at least eight people.
Returning for a second phase of excavation at the end of March, the ORCA team retrieved more remains — around 1,000 pieces of human bone — and painstakingly recovered samples of bone for DNA analysis from remains found within one of the structure’s undisturbed, and sealed, chambers.
Just like the excavation towards the end of 2010, the latest dig was another race against time. Concerns remain that changing environmental conditions inside the tomb could still adversely affect the remains inside.
The semi-subterranean tomb was built into a quarried-out rock outcrop — a natural feature that may have been of significance to the Neolithic inhabitants of the area before they constructed their tomb. After quarrying out rock to allow construction to begin, the builders created a central chamber measuring approximately four metres long by 75 centimetres across and aligned east to west. Access to the interior of the tomb was by a north-facing entrance passage.
Two large cells were built at either end of the main chamber, one was built to the north and two in the southern wall. These cells were capped by large waterworn stones — one of which had alerted the landowner, Hamish Mowatt, that there was something within the mound.
The second excavation focused on the structure’s west cell — a section that had been badly damaged by JCB work in the past — and one of the two sealed southern cells.
Leading the team was Dan Lee, projects officer with ORCA.
He explained: “Our main priority was to excavate into the western cell and see whether we could find any skeletal remains inside. We also looked further at the entrance passage, as we were keen to examine the deposits that had been used to seal off the tomb.”
Only a handful of the county’s chambered tombs have been excavated in modern times — most were the subject of “investigations” by antiquarians in the 19th century — but work on the Banks tomb is providing the first opportunity to study the undisturbed burials of a Neolithic community in decades.
As such, the excavations are allowing the experts to utilise the full range of cutting-edge archaeological techniques to fully examine the life of the structure — its construction, use and eventual decommissioning.
“The west cell was cut into the bedrock and had been lined with interior walling,” said Dan.
“It was basically the sump of the site, and waterlogged, so we began by removing and wet sieving the silty material at the top of the chamber. This was found to contain fragments of human bone, so, not long into the excavation, we had an idea that there would be more remains in the lower levels.”
And there were.
Dan continued: “We had to work down through the layers, recording everything very meticulously. What we were dealing with was an incredible assemblage of disarticulated human bones.
“All parts of the human skeleton were represented, including tiny bones such as fingerbones, sternums and kneecaps, and covering all age ranges, from very young children, perhaps babies, to adults.
“We found that there were actually stages in the burial sequence, with later users covering the earlier remains with the silty material in the tomb before depositing the new burials. So we got a layer of human bones, all jumbled up, sitting on top of a layer of silt that had gathered when the tomb wasn’t being used and then, under that, another collection of bones, also sitting on top of an earlier deposit.”
He continued: “Under this successive sequence of layers of bone and other material we managed to get down to the floor of the west cell, which consisted of a layer of clay that disappeared under the cell’s walls. This clay base was laid down during the initial construction of the tomb and underneath this was the natural bedrock.
“We achieved our goals, and this now gives us a really good indication of what to expect in the tomb’s other cells.”
It is hoped that dates can be obtained from the final closing deposits, and from the earliest burials in the west cell, which will show how long the tomb was in use. Dating evidence will also build up a picture of how often, and for how long, each phase of use lasted.
Dan added: “The only artefacts found, this time, were a coarse stone tool from a later phase of use, and a fragment of deer antler. There were none of the axes or maceheads found at other tombs, but it may be that these have been reserved for the passageway, central chamber or other cells.”
Based on layers of silt found inside, the archaeologists have established that water levels inside the tomb fluctuated over time, something that may have played a part in the structure’s use. Ritual activities associated with water are known from the Neolithic right through the Bronze Age and into the Iron Age. At Stonehenge, for example, it is thought that people making their way to the monument deposited the cremated remains of their dead in the River Avon.
In the Bronze and Iron Ages, items and human remains were deliberately deposited in bodies of water. In these periods, water seems to symbolise a portal, or crossing, to the otherworld. This is particularly interesting when it is considered that keystones used in the tomb’s construction did not come from the quarry itself, but were sourced from a nearby beach. This apparent significance of water-worn stone, and the evidence of water inside, hints that the ingress of water may have been key to the periods of the tomb’s use.
Dan said: “The water inside the structure may have dictated its use over time. If, for example, it was filling with water in the winter months, maybe they were only going in there in the summer. But it is also possible that they just weren’t worried about the water and it played its own part in the role, or symbolism, of the tomb.
“We also know from large quantities of otter spraint found inside the tomb, at different levels, that it must have been left open for extended periods of time — thus allowing otters to come and go as they pleased.
“We’d found evidence of otters using the tomb at the higher, later, levels of the structure within the closing deposits in the northern, eastern and southern cells, but, this time, what we found in the west cell was that the otters had been using the tomb, and certainly the west cell, throughout the entire life of the structure; right from the very earliest stages of its construction. As well as the otter droppings, there were otter bones and fishbone, presumably the animals’ food.
“It doesn’t seem to have been a problem that the otters were living in this tomb at the same time as the community that first built it, and those who later used it, were burying their dead there. This is particularly interesting. Did these otters also have a role, or significance, for the nearby community?”
“One thing is clear, though. This tomb would have been an awful place to get in and out off. The chambered tombs we can visit today have been cleared out, cleaned and sanitized, but we can see from working at Banks just how difficult it would have been to access. Anyone entering would have been covered by mud, silt and probably bits of people- not to mention having to negotiate flooded areas or sections.”
The waterlogged conditions within the tomb are responsible for the remarkable state of preservation of the remains recovered so far.
In waterlogged anaerobic conditions, where oxygen is excluded, preservation of bone is generally good. The absence of oxygen means the bacteria that break down organic remains cannot survive. However, if the water table drops, as is feared may happen at Banks, oxygen can get to the remains and decay begins immediately.
“Because the conditions are changing inside, there is now a real danger that we’re going to lose key information. The next stage will be to fully excavate the passageway and the entrance, and we hope to get back in the autumn of this year, or the spring of next, to continue working on this fascinating piece of Stone Age archaeology.”
The excavation was funded by Orkney Islands Council and the Scapa Flow Landscape Partnership. The excavation team would also like to thank landowners Hamish Mowatt and Carole Fletcher for their assistance and hospitality.
The Banks Tomb is open to the public, from 10am to 5pm daily, until October 31. As well as guided tours, a camera, linked to a monitor, allows visitors to see the interior of one of the rock-cut chambers. Admission costs £5 for adults, while children under 16 are free. The money raised will be used to enclose the tomb at the end of the season.