Unstan Chambered Cairn

Unstan Chambered Cairn stands on Mainland in Orkney, in the parish of Stenness, on a low promontory that runs into the Loch of Stenness near the settlement of Howe. It is also called Onstan and Onston, and the mound is the Knowe of Unstan, the Knowe of Onstan, and the Knowe of Onston. A plaque on the site uses Knowe of Onston. Written forms of the same name include Onsta in 1546, Onestone in 1576, Unstane in 1595, and Unstoun in 1627.

The pronunciation has stayed much the same while the spelling has moved. The second part of the name comes from an Orcadian form of the Norse word for a farm or dwelling-place. The first part is not known.

The place sits about 2 miles, or 3 kilometres, north-east of Stromness, and a few hundred yards north-east of the Bridge of Waithe, where the loch meets the sea. Maeshowe lies about 2.5 miles to the north-east. The grid has been given as HY 283 117, as HY 2829 1172, as HY 2828 1172, and, from a hand-held reading, as HY 28291 11713. The point has been given as 58 degrees 59 minutes 12 seconds north and 3 degrees 14 minutes 58 seconds west, as latitude 58.9866 and longitude 3.2494 west, and as latitude 58.98658 and longitude 3.24943 west.

One visit put the ground at 14 metres above ordnance datum.

Prehistoric Orkney, in the sense of the islands before written history, runs until about AD 600. No trace has been found there of archaic people in the Early or Middle Paleolithic. For much of the last glacial period the islands lay under the British-Irish ice. Late Upper Palaeolithic tools of the Ahrensburgian kind have been found on Stronsay and at Brodgar, and they have been read as visits around or before 8000 BC, perhaps as early as 11,000 BC, while Britain was still joined to the continent by Doggerland.

Rising seas in the early Holocene split the land. By 8000 BC Orkney was two islands, and by 6000 BC the outline was close to the present one. Hazel, birch, and willow, with some Scots pine, are thought to have covered much of the ground. The Mesolithic record north of Inverness is thin.

Small stone tools and chippings have come from Seatter, South Ettit, Wideford Hill, Valdigar, and the Loch of Stenness. A charred hazelnut shell from Longhowe in Tankerness has been dated to 6820–6660 BC. Nothing in that scatter shows whether people stayed all year. Those earlier traces are not objects from this chamber.

The sandstone of the islands is easy to split. Blown sand, little deep ploughing, and a habit of leaving old stone alone have helped monuments survive. The Neolithic, once farming was taken up, left far more building than the periods before it. The Bronze Age that followed is poorer in monuments here.

The Iron Age returned to large stone works, especially brochs. Four of the Neolithic remains are grouped as a world heritage site. This cairn is not one of those four.

The tomb is a Neolithic chambered cairn used for communal burial. It belongs to the broad tradition of stone-built chambered cairns that began in Scotland in the fourth millennium BC. It has been called a particularly well preserved, and unusual, example of an Orkney–Cromarty cairn. Cairns of that stalled kind have a central passage with pairs of upright slabs that divide the sides into compartments.

Early investigators compared the compartments to horse stalls. The earliest stalled tombs of this family are in Caithness, and they often have no more than four compartments. In Orkney the plans grew more elaborate. The Knowe of Ramsay on Rousay reaches fourteen compartments.

Unstan is a modest member of that series, with five compartments. Stalled cairns, or Orkney–Cromarty cairns, are the name used for rectangular chambers divided by orthostats, often under round or rectangular mounds, with end chambers closed by large back-slabs and with shelf-like or bench-like stones.

Unstan does not sit neatly in either of the two main Orkney types. The other type is the Maeshowe tomb: a high central chamber with small cells opening from it, usually under a round mound, entered along one side rather than at the end. Unstan has the rectangular stalled chamber of the Orkney–Cromarty type, and it also has one small side cell, a feature typical of Maeshowe-type tombs and rare beside stalls. The side cell is set in the wall opposite the entrance.

The passage enters the long side of the chamber, at right angles to it, which is again more like Maeshowe than like a typical stalled tomb. The only other excavated Orkney cairn known to combine stalls and a side cell is the tomb at Isbister on South Ronaldsay. Blackhammer on Rousay is the other Orkney–Cromarty cairn whose passage enters at the side rather than at the end. The outer stonework at Unstan is laid on a diagonal, as at Blackhammer and at Midhowe on Rousay, over a projecting foundation of horizontal slabs.

Finds from Isbister, Blackhammer, Midhowe, and Maeshowe are not finds from this chamber. They are the comparisons used to place the plan.

The mound has been called circular, 13 metres or 43 feet across, and also oval, stretched a little along the chamber, and measured at 13.7 by 13.0 metres. A 1952 account sets the concentric stonework at two rows, and also at three. A later reading of the plan separates a core of about 9.2 by 10.3 metres, a primary casing of about 11.2 by 12.3 metres, and an outer casing of about 14.0 by 13.5 metres. The outer layer stood lower than the inner work.

That lower height may be the result of stone robbed away, or it may have been built lower on purpose, as at other cairns with the same layered build. The inner two layers were nearly as tall as each other. Before the dig, the knowe looked like an ordinary Orkney tumulus, with an unbroken slope. That slope was stone that had slipped off an outer wall of larger blocks, which still stood some feet high where it was intact.

There was a hollow in the top. It looked like a mound already opened, but it was read as the roof having fallen in, and the hollow was said to have grown deeper in the years just before 1884.

The walls that remain are thin stacked slabs of local flagstone from the Old Red Sandstone of Devonian age. They have been measured at almost 2 metres, or 6.6 feet, at up to 2 metres, and at 2.05 metres. The original roof of the main chamber had already gone when the mound was opened, so the original internal height is not known. A modern concrete dome now covers the chamber.

One account dates that dome to the 1930s. Another dates the roof, and the opening of the tomb to visitors, to 1949. The turf profile people see from the loch is the twentieth-century roof and the work done with it, not the Neolithic silhouette. The mound is still visible for a long way around the Loch of Stenness, which lies in a National Scenic Area.

The entrance passage is on the east. Its compass direction in 1884 was a little north of east, as nearly as could be judged the opposite direction from Maeshowe. A later landscape account places a single entrance to the west. The 1884 plan and the later measured plans put the passage on the east.

The passage has no door-slab of the Maeshowe kind. In 1884 the roofing stones, some flat and some on edge, ran 11 feet in from the interior. Below the last roofing stone was a downward step of about a foot, made by one large stone laid across, with rough building outside it up to the same level. At the inner end, two walls of small stones converged to a gap of 14 inches and were compared, by a workman on the dig, to the bow of a ship.

One of those walls, and part of the other, had to be taken away before the passage could be cleared. Later measurement gives the passage as 6.5 metres long and between 40 and 60 centimetres wide, the longest entrance known on an Orcadian stalled cairn, and not placed on the centre line, so that it misses the side cell on the opposite wall. Another account says the passage was originally 6.5 metres and that the outer part has been destroyed, leaving about 5.7 metres, of which about 3 metres is roofed today with a modern reconstruction. The same visit found no record of the original passage height, described the present passage as over 2 metres high, and doubted that this was the old height, because other intact cairn passages on Orkney have to be entered on the knees.

A bearing of 70 degrees true was taken along the passage on that visit, and the direction from the cairn to the Stones of Stenness was plotted at the same figure. The visitor suggested that the passage was built toward that view. That alignment is a suggestion from the bearing, not a result recorded in 1884.

The chamber in 1884 was 21 feet long and about 5 feet broad on average. Later measurement gives a sub-rectangular chamber 6.6 metres long, about 1.52 metres at its widest and tapering at each end, and also about 6.6 by 1.9 metres. Another account gives the five chambers as flanking a passageway 6.4 metres, or 21 feet, long. Four pairs of large flagstones project from the side walls and make five compartments: three central stalls and two end sections, with a stone-flanked walk down the middle.

The passage does not enter the central, third compartment. It enters the second from the south. The distance from the south-east corner to the middle of the passage was exactly one-third of that wall. The whole plan is irregular.

Few walls are straight, and the wall on one side of a dividing slab rarely lines up with the wall on the other. Low threshold stones close the gaps into both end compartments. The end walls, and the back of the side cell, are each formed of one large flagstone with building above it. Stones projecting from the side walls of the end compartments, at about 1.2 metres above the floor, have been read as supports for a shelf or bench.

No shelf was found in 1884. The supports may have broken, or been missed, or have been wood that rotted. In the first compartment the projecting stones sit about 3 feet 4 inches above the clay, and there are five of them, about the size of a hand. In the fifth compartment they sit about 4 feet above the clay.

Walling survives above some of the dividing slabs, so those slabs did not carry the original roof. The central pair in the west wall is damaged: the northern stone is essentially gone, with scraps left in its groove, and the southern survives as a base about 0.3 metres high. The dividing slabs have been measured from 1.55 to 2.0 metres tall. On one reading of the plan the eastern stone of a pair is almost twice as wide as the western, the extra width buried in the wall.

White clay covered the chamber floor. The end compartments and the side cell also had areas of stone paving. A black layer, rich in charcoal and described as ashy or earthy, and in one place as a mixture of peat and charcoal, covered the southern end and ran a couple of feet into the third compartment, the first compartment, and the passage. Among unburnt bone in that black layer were chips and flakes of flint that showed the action of fire.

The first compartment, south of the entrance, is 4 feet 9 inches long on the east wall and 4 feet 1 inch on the west. The end wall is 4 feet 9 inches wide and opens to 5 feet 6 inches at the dividing slabs. The gap from the second compartment is slightly over 2 feet at the base. Inside it, a stone 1 foot high and 2 feet 9½ inches long lies edgewise, and a line of similar edge-set stones runs from it to the south wall, cutting the compartment into two nearly equal parts.

The eastern part is roughly paved about 6 inches above the western part, which, like the rest of the chamber, was floored in white clay. This compartment was much clearer of soil than the others and could mostly be cleared by hand. It held a considerable quantity of bone, partly human, the black peat-and-charcoal substance, the bottom of a small flat-bottomed urn, and other pottery.

The second compartment, which the passage enters, has side walls 4 feet 8 inches long. Because the dividing slabs are not square, the shortest length is 4 feet 3 inches. The width runs from 6 feet 3 inches to 5 feet 6 inches. Most of the relics in the chamber were here.

Beside the south-west slab was a small space without white clay, and in it were fragments of different urns. A sherd from the fourth compartment fitted an urn whose other pieces were in this second compartment, which was taken to show how thoroughly the contents had been scattered. Over the clay lay the black charcoal-rich stratum, with great quantities of pottery and several flint chips and flakes. Several fragments of bone were in the floor itself.

None of them showed burning. On top of the black layer lay several burials in the contracted posture.

The third compartment, north of the entrance, measures from 5 feet 8 inches to 6 feet 1½ inches east to west, and a little over 4 feet north to south. It held a large quantity of bone, including several large vertebrae close to the door of the side chamber. The only relic besides a few pottery fragments was a flint implement 3¼ inches long, of the class Mr Evans called fabricators or flaking tools.

The side chamber opens west from that third compartment. Two large upright stones form a short passage for a door. Later measurement gives the doorway as 0.4 metres wide and 0.85 metres tall, and the cell as 1.45 metres deep and 1 metre wide. Unlike the main chamber, the roof here was entire in 1884, 3 feet 6½ inches high.

A rude floor was a flagstone small enough to have been brought in after the cell was finished, resting on blocks. There were two distinct burials in the contracted posture. One skull was the most complete found, and even that was scarcely half present. Near the door was a tooth which Dr Garson identified as that of a small dog.

A stone pounder lay under the bones of one skeleton, and two flakes were with it. Those were the whole of the relics listed in the cell. A later account says the side cell held no pottery. The present lintel of the doorway, and the walling above it, are restoration.

One reading of the cell has two roof lintels, one flat and one on edge. Photographs from a later visit show two flat lintels divided by one set on edge.

The fourth compartment measures 5 feet 7½ inches east to west and about 4 feet from door to door. It held only a few pottery fragments and a quantity of bone. The east side seemed to have a rude pavement like that in the first compartment.

The fifth compartment, at the north end, is the smallest. It is only 3 feet from the door to the end wall, and the sides taper northwards to 3 feet 9 inches. It has the threshold stone and the large end flagstone already noted, and the projecting stones at about 4 feet. Large stones lay on the floor and may once have carried a flagstone, as in the side cell, but if so the flag was too broken to recognise.

A small and rudely formed arrowhead was found here, with some burials and several small pottery fragments. Higher than any other relic was a small piece of ornamented pottery of a pattern different from all the others.

Human bone was in every compartment: disarticulated bone, burnt and unburnt, and complete skeletons among them. The number of people is not known. The bone was not fully studied at the time, and only a few pieces survive. Dr J.

G. Garson, of the Royal College of Surgeons of England, was sent the bone. Ahead of a fuller report, he recognised fragmentary remains of several human skeletons and a large quantity of animal bone. He identified horse, ox, sheep, swine, and dog, and numerous bird bones, some from birds of considerable size.

A later retelling of the same animal list also names deer. No total of bodies is given beyond those several skeletons, the several contracted burials on the black layer in the entrance compartment, and the two contracted burials in the side cell. One public account says the human bones were piled in all five stalls and that the two crouched skeletons in the side cell were likely the last burials, perhaps meant to be moved later into the stalls with the other bone. Another reading says crouched burial was not a Neolithic practice, so those bodies belong to a later use.

A third reading places the crouched inhumations in a later phase and treats them as evidence that the tomb stayed in use, if only at intervals, from the early Neolithic into the early Bronze Age.

Joseph Anderson examined the pottery. He judged that the sherds represented somewhere about thirty different vessels, of which only six or eight could be rebuilt far enough to show the full form and the ornament. The count has also been given as parts of twenty to thirty bowls, as fragments of over twenty bowls, as at least thirty, and as at least thirty-five. Many were decorated.

Most of the sherds lay in the entrance compartment. A few were elsewhere in the chamber and in the passage. The bowls are shallow and round-bottomed, with incised motifs under the rim. The decoration has been called stab-and-drag.

A second version is the plain round-bottomed bowl. Some clay had pieces of volcanic rock in it. After firing, bone tools were used to burnish surfaces. Some sherds carry impressions of barley grains, so the bowls had been used before they were placed with the dead.

Many were shattered or incomplete, which is common in chambered cairns and has been read as deliberate breakage. Fragments also lay in a shallow hollow in the clay floor, a pattern known in other tombs. The use of the bowls inside the tomb is not known. Food, drink, provisions for the dead, offerings, or tributes to ancestors have all been offered as guesses.

The largest rebuilt urn is reddish clay, softer and more porous than the rest, and thicker in the body. It is 15½ inches in diameter and 5½ inches deep at the centre. The broad flat lip is 1¼ inches across. Under it, a slightly curved rim carries scorings of oblique lines.

The form has three parts: a round bottom, an upright brim, and a flat but slightly bevelled and everted lip. Ornament is only on the upright brim. The next urn is 14 inches in diameter and 5 inches deep, dark, hard, and free of stones in the paste, almost as even as if it had been thrown on a wheel. The lip, bevelled from the inside outwards, thickens to ¾ inch.

The vertical rim is 2½ inches high and is scored obliquely to right or left in alternate triangular spaces. There is no ornament anywhere else on it. Another, slightly oval, is 13½ inches in diameter and 4¾ inches deep, with a vertical rim only 2 inches high, a lip almost flat and ⅝ inch thick, and alternate triangles set parallel to the lip and obliquely to the left. Another is 11¾ inches in diameter and 4¼ inches deep, the lip flat and ⅝ inch thick, the rim 2¼ inches high, ornamented like the first but with two horizontal lines under the brim.

A smaller one of the same character is 9¼ inches in diameter and 3¼ inches deep. Rims of two further urns, 10½ and 10¼ inches across, are extremely thin and carry triangular spaces like the second urn. Fragments of another variety have the rim slanting outwards. A plain oval vessel is 9 inches across at the mouth in its greatest diameter and 4 inches deep, with bulging sides that contract to a rounded bottom.

Another plain form, known only in fragments, seems to have had deep, almost straight sides and a rounded bottom, a tall can-like shape whose full proportions were not recovered. Only one flat base was found, about 3½ inches across, and its upper part is missing. The prevailing type is therefore a round-bottomed vessel of hard dark paste, with a vertical brim and a thick flat or bevelled lip. Anderson noted the same round-bottomed, thin, hard, dark paste in the chambered cairns of Caithness, and a similar round-bottomed form from Canon Greenwell’s work at Largie in Argyll and from the urns Dr R.

Angus Smith found at Achnacree. Those are other cairns. Their pots are not this tomb’s pots. Several of the rebuilt Unstan bowls, and some of the skeletal remains, went into the national collection in Edinburgh, then the National Museum of Antiquities of Scotland and now the National Museums of Scotland.

The flint, except for one oblong sandstone pounder, had all passed through fire. Anderson listed four leaf-shaped arrowheads, large and well made, tending to an elongated lozenge with a curving butt, and one smaller barbed and tanged arrowhead, damaged but still recognisable. A later account of the same flint counts five leaf-shaped arrowheads and a plano-convex knife as early Neolithic, and treats a retouched fabricator from the central compartment, and a broken barbed and tanged arrowhead, as early Bronze Age. The barbed arrowhead was found in the passage in 1884, together with a flint scraper and some pottery.

It has also been placed in the northernmost compartment, and again in the entrance passage. The fabricator is a long ridged flake, nearly triangular in section, worn at both ends. Anderson called it the first recorded example of that tool in a Scottish burial. Its use was presumed to be the making of arrowheads and other flint tools.

A later reading says it had been in a high-temperature fire, possibly a cremation pyre. There was also a finely finished scraper with both sides and the front bevelled, a form not common in Scotland, and a flint knife with the edge ground smooth rather than only chipped. Ground-edged knives were already known from chambered cairns in Caithness. A later catalogue of the flint also lists more than thirty pieces of debitage, many of them scorched, a naturally perforated flint pebble, an edge-ground flint knife, and a broken square-ended scraper.

The pottery gave its name to Unstan ware, the shallow round-based bowls with a decorated band below the rim, treated as the type fossil of the early Neolithic in Orkney and as part of the wider round-based bowl tradition of Britain. Until the same ware was found at the Knap of Howar on Papa Westray, it was known in Orkney only from tombs. Those two houses were once placed at about 3700–3600 BC. A redating puts the first activity there around 3500 BC and the buildings that stand today around 3300 BC.

That settlement is not this cairn. Unstan ware was long thought to have been replaced around 3200 BC by Grooved Ware. A 2017 reassessment of Orkney radiocarbon and luminescence dates, by Alex Bayliss, Peter Marshall, Colin Richards, and Alasdair Whittle, concluded that round-based pottery and Grooved Ware were almost certainly in use at the same time during the thirty-first century calibrated BC, at the very least.

Dates for the cairn itself have been given in several ways. It has been placed at about 5,000 years ago, at about 3100 BC, and, from evidence at nearby tombs, sometime between 3400 and 2800 BC. By analogy with other sites it has been placed between 3500 and 2500 BC. Until 2017 the pottery only supported an early Neolithic date.

Three fragments of unburnt human bone from the 1884 dig, held in the national museums, were then radiocarbon dated. The results have been given as around 3350–3100 calibrated BC, and as around 3300–3100 BC. Those results date use, not necessarily the building. The chamber may be centuries older, cleared or reused at intervals.

What they do show is that the chamber was standing and in use by about 3300 BC. An arrowhead of the kind used by the Beaker People has been used to argue that the tomb may still have been a focus well into the second millennium BC. The Beaker People, also called the Bell Beaker culture, the Bell Beaker complex, and the Bell Beaker phenomenon, take their name from an inverted-bell drinking vessel at the start of the European Bronze Age. The German name Glockenbecher was coined by Paul Reinecke, and John Abercromby introduced the English name Bell Beaker in 1904.

The culture arose as early as 2800 BC. It lasted until about 1650 BC in some regions and disappeared as early as 2300 BC in others. In Britain it is placed from about 2450 BC, when single graves appear, until as late as 1800 BC. In central Europe it is placed only until 2300 BC, when the Únětice culture followed.

It is spread through Iberia, east to the Danubian plains, north to Britain and Ireland, and also in Sardinia, Sicily, and parts of the north-west African coast. A study of 2018 found the people associated with it to be genetically diverse. Early maritime beakers at the Tagus estuary in Portugal have been radiocarbon dated to the twenty-eighth century BC. In its mature phase the culture is treated as more than a set of pots: copper, arsenical bronze, and gold, long-distance exchange, archery, particular ornaments, and, it is presumed, shared ideas, with social ranking and regional elites, while local burial, housing, and pottery still varied.

The barbed and tanged arrowhead at Unstan is the link drawn between this chamber and that later culture. It does not by itself name the dead.

The land in 1884 belonged to William Leith, who gave Robert Stewart Clouston permission to open the knowe in July 1884. Local papers described the excavation in September 1884. Clouston began on the east, where the cairn surface dipped slightly, and within a few feet reached the passage roof. This was the first cairn opened in that century in Orkney to produce finds in any quantity, and it remains one of the few there with human bone.

After the objects were removed, the structure was left open to the weather for about half a century. A note of 1907 says the mound was still open. In 1934 it passed into state guardianship, and the Ministry of Works cleared it further, repaired damaged stonework, and added a lintel. In 1949 the remains were consolidated, a concrete roof was added, and the interior was made accessible.

The side-cell lintel was replaced and the walling above it was rebuilt. A concrete cover of the kind used on Rousay in the 1930s was chosen rather than a full shelter of the sort later considered, and of the sort used at Midhowe. Green algae now grows inside, a result of that roof, and it hides some of the faint marks on the stone.

The interior carries modern graffiti and a smaller set of carvings whose age is debated. Two runic inscriptions are judged modern, after the 1884 excavation, and have been linked to a modern Orcadian interest in runes that followed the discovery of the runes at Maeshowe. An incised bird, often called a diving bird, on the lintel over the side-cell door existed before 1935. It may also be later than 1884.

It has been compared with Pictish carving elsewhere, and that comparison is uncertain. The words “Pictish marks” cut beside it are modern and fall between 1884 and 1935. A later reading says the bird was not noted during the excavation, so the carving, and the other graffiti, date from the late nineteenth or early twentieth century, and that the hill and the diving pose have been read as the loch with the hills of Hoy behind them. The inventory classes the inscribed stone as Norse.

The significance assessment classes the two runic inscriptions as modern. The lintel that carries the bird and the runes is a replacement, and it is absent from a photograph taken during the excavation, which leaves open whether the carving was visible when the stone was first used. Carving graffiti on the monument is forbidden by law.

North of the cairn, the headland of the Ness of Onston, or Point of Onston, is cut by earthworks. In 1884 Clouston described a single moat within about 20 yards of the knowe, running from shore to shore, crossed nearly opposite the mound by a narrow passage of filled earth. A 1952 guide places two curving parallel lines of low rampart and ditch some 180 yards inland from the tip of the promontory, and says that a single line might have been read as an animal enclosure, while the double line leaves the purpose and the date obscure. A visit of 1928 recorded two carefully built lines.

The ramparts were then only 2 to 3 feet high, apparently upcast from the ditches. The outer ditch was 19 feet from crest to crest and the inner 16 feet. Slight gaps in the lines might mark an entrance. By 1966 the works were best preserved on the east, destroyed in the centre by cultivation, and reduced on the west to three vague rises.

A later measurement gives both ditches as 3 metres wide, with banks surviving to about 60 centimetres. The feature is officially classed as a promontory fort. Its age is not known. An Iron Age date is the common suggestion.

Banks and ditches around funerary ground are also known in the Orcadian Neolithic. Aerial photographs have been read as if the lines once continued under the loch, which would mean a larger enclosure built before the water stood at its present level. Survey on shore and offshore in 2011 and 2012, part of the Rising Tides work, did not find the earthwork beyond the present shoreline. The surveyors added that lost sections, if they had been built in sediment on the bedrock, could have been eroded away with that sediment.

A resistivity survey in 2007, part of a wider look at the world heritage area and its edges, showed the ditches and banks clearly and showed anomalies inside the enclosure that may be stone structures. Magnetic survey found no definite features, which was taken to suggest that the enclosure was not primarily a settlement. Hugh Marwick’s judgement of 1952 still stands in the sense that excavation would be needed to date it. Little is known of this fort, and it is not the chamber.

In May 2001 a trench for a new fence around the cairn, dug by D. Murray and G. Ewart, found no definite prehistoric remains. In May 2002 a new track and car park, dug by G.

Ewart and D. Murray, produced no significant discoveries. An Ordnance Survey visit on 11 May 1966 found the monument as Audrey Henshall had planned it. Henshall had published a plan and sections in 1963, and with J.

L. Davidson a fuller account of the Orkney chambered cairns in 1989. V. Gordon Childe and W.

Douglas Simpson described the monument in 1952, including the passage length, the concentric stonework, and the bowls in the museum. Nothing is known of a settlement that might have belonged with the tomb. Two projecting walls near it have been noted as a hint of nearby activity, and the idea that each tomb had a neighbouring settlement, as argued for Maeshowe, Quanterness, Cuween Hill, and Wideford Hill, has not been tested here. Those other tombs are not this one.

The cairn is intervisible with many prehistoric sites. It lies beyond the inner buffer of the Heart of Neolithic Orkney world heritage site, whose four principal monuments are Maeshowe, the Stones of Stenness, the Ring of Brodgar, also spelled Ring of Brogar, and Skara Brae. The Ring of Brodgar and its mounds can be seen from Unstan, and so can the Ness of Brodgar. A world heritage account of related monuments calls the Knowe of Unstan an early Neolithic chambered cairn on the southern shore of the loch, a green mound divided inside into stalls with a small side chamber.

The same group of cared-for tombs used as comparisons includes Midhowe, Blackhammer, the Knowe of Yarso, Isbister, Maeshowe, Wideford Hill, Cuween Hill, Quoyness, the Holm of Papa Westray, and the Dwarfie Stane, together with the Barnhouse Stone, the Watch Stone, the Stones of Stenness, the settlement at Barnhouse, and, for house plans rather than tombs, the Knap of Howar, Skara Brae, and the Links of Noltland. None of those sites is this chamber, and none of their excavated objects should be counted among the Unstan finds.

Other stone monuments of the same broad age of building in large stones lie far from Stenness, and they are not part of this cairn. The Almendres Cromlech, near Évora in Portugal, is a complex of cromlechs and menhirs, the largest structured group of menhirs in the Iberian Peninsula. Henrique Leonor Pina found it again in 1966 during geological mapping. Its building has been placed in the sixth millennium BC, with phases at about 6000 BC, 5000 BC, and 4000 BC, running from the Neolithic into the Chalcolithic.

About 95 granite monoliths stand in an area of about 70 by 40 metres. Mario Varela Gomes re-erected many of them on bases found where the stones had fallen. A religious or ceremonial use, or a rough astronomical one, has been suggested, and not demonstrated. Auld Bourtreebush is a Neolithic stone circle near Portlethen in Aberdeenshire, also called Old Bourtree Bush and Old Bourtreebush, about 25 metres across, thought to have had up to fifteen orthostats, of which four still stand.

A ring cairn inside it has been destroyed. It was once called a recumbent circle, and that reading is now rejected. It lies near the Causey Mounth, the high medieval road from the Dee crossing toward Stonehaven. In 1639 William Keith, 7th Earl Marischal, and the Marquess of Montrose led a Covenanter army of 9,000 men along that road.

That march is the later history of the Aberdeenshire track, not an event at the Loch of Stenness. Barbrook One is an embanked stone circle on Ramsley Moor in the Peak District. One stone is about 1 metre high and eleven are 5 to 25 centimetres high. The internal diameter is about 13 metres, inside a rubble bank about 3 metres wide.

Barbrook No. 2, a ring cairn of similar internal diameter, lies about 200 metres to the north by north-west, and about eighty cairns, most of them under 6 metres across, stand on the moor. The local saint William Hale is said to have used these circles when converting local pagans. Barbrook No. 3 lies about 2 kilometres to the north. Bedd Arthur, Arthur’s Grave, is a possible Neolithic hengiform setting in the Preseli Hills of Pembrokeshire.

Thirteen uprights and at least two fallen stones, each about 0.6 metres high, form an oval or horseshoe about 20 by 10 metres. The site has not been excavated. It looks over Carn Menyn, suggested as a source of some Stonehenge bluestones. A 2011 study matched one rhyolite group at Stonehenge to an outcrop at Rhosyfelin, about 3 kilometres north of Bedd Arthur.

A 2015 study at Rhosyfelin found no sign of quarrying. The Arthur name is local folklore, shared with other Pembrokeshire stones, and it is not a record of a burial identified in the ground. Beglik Tash is a prehistoric rock sanctuary on the southern Black Sea coast of Bulgaria, a few kilometres north of Primorsko, reused by Thracians in the Iron Age. Karel Škorpil wrote the first scientific account at the end of the nineteenth century, when it was called Apostol Tash.

Excavation from 2002 was led by Tsonia Drazheva. Ceramics of the Early Iron Age, the tenth to sixth centuries BC, of classical antiquity, and of the Middle Ages have been found, with a made stone altar in a natural cave. Alexander Fol read the noon sun in such caves as a Thracian image of the sun and an earth goddess. The place is an open-air museum and has drawn about 40,000 visitors a year.

Brennanstown Portal Tomb, also called the Glendruid Dolmen and the Cabinteely Dolmen, is a portal tomb in County Dublin, a national monument, on the north bank of the Carrickmines River about 1.2 kilometres south of Cabinteely. Little else is recorded of it. None of these monuments supplied the stone, the dead, or the bowls at Unstan.

What the cairn changed is the name and the type of a pottery, and the evidence for how an early farming community on Mainland treated its dead: bodies taken apart and also, later or last, laid crouched; bowls broken and spread; flint that had been in fire; a chamber kept or revisited long enough that early Neolithic bowls and a later barbed arrowhead occur in the same tomb. What is missing is a count of the dead, a date for the first building separate from the later bone, a date for the earthwork on the headland, and any excavated trace of the people who lived beside the loch and raised the mound. The chamber can be entered by the original passage. Entry is free, and the cairn is open year-round.

The approach road is not suitable for coaches. Carving graffiti is not allowed.