The Bookan Chambered Cairn
By Sigurd Towrie
At some point in the Neolithic a small, multi-chambered structure was built on high ground at the north-western end of the Ness of Brodgar.
Although it had clearly been used for the deposition of human remains, Bookan’s architecture is different to most of the known chambered cairns in Orkney.
With an approximate diameter of 16 metres (52.5ft), it was first investigated in 1861, when it caught the eye of the antiquarian James Farrer.
As regular readers will know Farrer was “an assiduous if, by modern standards, unscientific digger of mounds” .
Very active in 19th century Orkney, his mound-breaking exploits were notable for the damage they caused, not to mention a lack of documentation.
In July 1861, Farrer’s sights were firmly set on Maeshowe and he had assembled a team to break into the chamber. Before that operation began, he decided to “open a barrow at the edge of the very large, ancient quarry near Bookan”. 
So he redirected his Maeshowe labourers to Bookan.
The Orcadian antiquarian George Petrie often accompanied Farrer on his endeavours – or in some cases followed in the wake of his destruction. Fortunately, Petrie was present at the ensuing “excavation” of the Bookan cairn and recorded the hurried incursion into the structure.
Farrer soon learned he was not the first to descend on the chamber.
It had been, wrote Petrie, “partially examined on some former occasion and the upper part was consequently in a very ruinous state”. 
As we will see, after the Bookan structure went out of use it was partially dismantled/demolished, so it is difficult to tell whether this was what Petrie encountered or whether there had actually been earlier antiquarian exploration.
In 1861, the mound survived to a height of 1.8 metres (6ft) and had a diameter of around 13 metres (44ft). Cutting into it, the excavators encountered a low, encircling stone wall at the base, circa 0.30m (1ft) high.
In the southern side, a 1.9-metre-long (6ft 3in) entrance passage, a mere 53 centimetres (1.7ft) high and wide, led into a “small chamber or kist (sic)”, 2.16m long (7ft 1in) and 1.22m (4ft) wide and “formed by large flagstones set on edge”. 
This was surrounded a four box-like chambers – one to the north, one to the east and two to the west.
At the north end of the central chamber was a flint “lance-head” and sherds of “small, clay vessels or urns”.
Some of the side chambers contained “[r]emains of human skeletons, greatly decayed.” 
To Petrie, “a glance was sufficient” to realise that what lay before him was a chambered cairn. It was, however, architecturally different enough for him to ponder the reasons why.
He concluded that if it was not for practical reasons – simply designed and constructed to make use of the flagstone from the nearby quarry – then Bookan must have been raised for someone whose social standing did not warrant a more elaborate structure. 
And that’s about as much detail as we have from 1861, although Farrer and Petrie’s explorations on the Calf of Eday in 1855 and 1859, revealed two chambers that are notably similar. Now known as the Calf of Eday North-West and Calf of Eday South-East, Petrie recorded that the former consisted of “a central chamber with four surrounding cells, formed by upright flagstones, with the usual passage from the outside to the interior.” 
Discussion surrounding Bookan over the following decades centred on the differences noted by Petrie at Bookan. These were continually problematic because they meant Bookan did not fit neatly into the “categories” of chambered cairns that were being established and used to try and construct a chronology for their development.
In 1886, for example, Dr Joseph Anderson suggested Bookan represented a link between the tripartite Orkney-Cromarty stalled cairns and the Maeshowe-type.
The suggestion that Bookan dated to the Early Neolithic continued and, almost a century later, the apparent simplicity of the layout and similarities to other suggested early cairns earned Bookan a category of its own – a sub-group of the Orkney-Cromarty type that was, back in 1989, still considered to be an Early Neolithic phenomenon. 
While the debate over Bookan’s typology, and its place in the timeline of Neolithic Orkney, continued apace, the condition of the cairn was deteriorating badly.
In June 2002, an excavation was launched to assess the extent of the damage. This also provided an opportunity to try and address the many questions still surrounding the structure, not least its date.
The excavation, led by Ness of Brodgar site director Nick Card, was enlightening to say the least. It revealed that the chambers documented by Petrie in 1861 were the first phase in the life of a structure that saw episodes of construction, demolition and remodelling. 
In its primary form, the cairn was oval-shaped, measuring seven metres (23ft) long by five metres (16ft) wide. Inside a two-metre (6.6ft) by 1.4-metre (5ft) rectangular central was surrounded by five, symmetrically arranged, chambers – two to the west, two to the east and one to the north. 
In this respect, the chamber’s spatial layout was not unlike the Orkney-Cromarty stalled cairns, such as Unstan and Midhowe, where the space between the entrance and a single chamber at the rear was divided into compartments, or “stalls”, by pairs of standing stone-like orthostats. 
But at the same time, Bookan exhibited elements of the Maeshowe-type cairns – particularly the concentric use of space and side cells. It could therefore be argued that Bookan straddles the two different styles.
Bookan’s five chambers were formed by a mix of large, load-bearing orthostats, c0.85m (2.8ft) high, and smaller orthostats creating divisions between them.
The side chambers were a mere 0.85m high, accessed by openings from the central chamber c 0.5m (1.6ft) high and 0.6m (2ft) wide.
Access was by a south-south-easterly facing entrance passage, two metres long (6.6ft), 0.5m (1.6ft) wide and probably around 0.85m (2.8ft) high.
The side chambers and passage were probably paved and surrounded by a wall between one metre and 1.5 metres thick.
The narrowness of this wall meant that Bookan could not have had a beehive-like, corbelled roof but was probably roofed by flat, stone slabs and capped with clay.
This suggests the roof of the central chamber, although still low, was slightly higher than that of the side chambers. 
Moving around that cramped, low chamber could not have been a particularly easy undertaking.
From the outside, Bookan would have looked like an “oval, rather squat, freestanding, vertical-sided structure, with a domed roof, a little more than two metres high”.
There was no evidence of a covering cairn of earth or stone, suggesting Bookan’s one-metre-high outer wall face was visible .
What was this small structure’s role?
Other chambered cairns in Orkney probably had multiple roles but given the size of Bookan’s tiny central chamber it is difficult to see how the same could apply – it clearly could not have held more than two crouched people at a time.
It was, however, clearly used for the deposition of human remains.
In 1861, Petrie noted “portions of skulls and other bones of human skeletons” in the north-western, northern and north-eastern side chambers.
Due to the acidic nature of the soil, these remains were poorly preserved. Phosphate analysis in the central and south-east chambers, however, suggested that bone was once present in all. 
The only human remains encountered within the structure in 2002 was a “small, discrete heap” of mixed bone lying on the floor of the north-western side cell.
Petrie was known to have left skeletal material behind at other excavations, which suggests that the 19th century excavators gathered up all the (moveable) human remains they found and left them in the cell. 
Unfortunately, their condition – which had been “extremely friable and decayed” 141 years earlier – and the fact they had been disturbed meant the Bookan bone assemblage could “add little to the debate concerning ‘mortuary ritual’ in the Neolithic.” 
Had there been major ceremonies outside the structure, perhaps to mark the deposition – or removal – of human remains, they left no recognisable trace.
Outside, two small, shallow scoops had been scraped out two metres (6.5ft) from the entrance and were filled with a dark material containing small amounts of charcoal, possibly from burnt heather. 
The only ceramics recovered during the 2002 excavation came from between these two pits – a small, abraded sherd of poor-quality pottery. 
A long-running debate surrounding chambered cairn is the question of whether they were deliberately blocked up and sealed after going out of use. At Bookan the excavators encountered stone slabs piled in the central section of the entrance passage.
Although it could be argued this was the last remnants of passage-blocking material, the archaeologists considered it unlikely. Instead, given the “haphazard nature” of the material, it was felt more likely that it represented the natural collapse of the passage walls. 
Blocked or not, Bookan had gone out of use – an event that was marked by its partial demolition. The orthostats, walling and flagged floor of the south-eastern chamber were carefully and deliberately removed and the entire structure partially dismantled and left to decay. 
But even though it had been reduced to half its original height, Bookan was not forgotten.
After an unknown period it became a focus of attention again and people returned to the ruins. Whether this was within living memory of its closure – and the people remembered those interred within – or after centuries had passed and the structure had slipped into the realm of myth is unclear.
What is without doubt is that it was deemed necessary to monumentalise the site.
To do this a large cairn was raised over the ruins and contained by three concentric revetment walls. Incorporated into the cairn material were six fragments of human rib.
The use of concentric walls is reminiscent of the walls around Maeshowe, Barnhouse Structure Eight and Structure Ten at the Ness. At the same time as creating a visible monument were Bookan’s remains being contained and enclosed?
The result was a three-tiered, stepped platform standing about a metre high. At around 16 metres (52.5ft), the diameter of the new construction was more than double that of the original.
While this has been the subject of debate, at Bookan the quality of the outer stonework implies “that the inner and middle revetments were designed to be visible for their full height.” 
Dating the cairn
One of the goals of the 2002 excavation was to secure dating material from the chamber. Unfortunately, the samples taken yielded nothing suitable. What human skeletal material had been recovered was in poor condition and not in a context that could allow the structure to be placed in a secure timeframe.
What this tells us is that although Bookan was probably abandoned and monumentalised in the Late Neolithic it remained a focus for the deposition of human remains for several centuries afterwards.
On present evidence, the most we can say is that Bookan was probably constructed in the latter half of the mid-fourth millennium BC and seems to have remained in use, at least episodically, for some time.
The pottery recorded by Petrie in 1861 – “clay cups or small vessels…with rudely formed raised moulding in a waved form encircling the upper part of one one or more cups”  – is long lost, but the description suggests it was Grooved Ware pottery with applied decoration, which would place it in the Late Neolithic (2900-2500BC) .
But that does not necessarily place the construction of Bookan in the Late Neolithic – just that it was in use at the time. The periodic clearing out of chambered cairns is a known phenomenon and earlier material from Bookan may have been removed in antiquity to make room for new deposits.
At the end of its life – based on the pottery, probably between 2900-2500BC – the chamber was partially demolished and monumentalised.
Like other Neolithic sites across Orkney, Bookan’s significance as a place for the deposition of the dead clearly survived into the Bronze Age and its presence may lie behind the construction of the funerary barrows that cluster around it.
-  Ashmore, P. (2000) Maeshowe. Historic Scotland: Edinburgh.
-  Petrie, G., 1863. The Picts’-houses in the Orkneys. Archaeological Journal, 20(1), pp.32-37.
-  The Bookan excavation was notable, however, in that it set Petrie on the path to unravelling the 19th century morass surrounding the so-called “Picts’ Houses” of Orkney – a blanket term used for a wide range of Neolithic, Bronze and Iron Age structures.
-  Davidson, J.L. and Henshall, A.S. (1989) The Chambered Cairns of Orkney: an inventory of the structures and their contents. Edinburgh University Press.
-  Card, N., Alldritt, D., Clark, A., Duncan, J., MacSween, A., Miller, J., Ramsay, S. and Wickham-Jones, C.R. (2005) Excavation of Bookan chambered cairn, Sandwick, Orkney. In Proceedings of the Society of Antiquaries of Scotland (Vol. 135, pp. 163-190).
-  Nick Card. Pers comm.