Stonehenge a New Understanding (41 page)

Just how the bluestones got to Stonehenge is a big question. The Welsh stones at Stonehenge are not particularly heavy. The largest, the Altar Stone, is estimated to weigh perhaps eight to ten tons, but many are likely to be no more than four tons. Even so, anthropological studies from different parts of the world show that moving any stone weighing over a ton requires more than just enthusiasm and brute force:
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There has to be some basic technology involved. Richard Atkinson demonstrated in the 1950s that just thirty-two schoolboys can drag a bluestone on a cradle using wooden rollers.
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If the bluestones came from Wales to Wiltshire by sea, just how did Neolithic sailors pilot flimsy boats or rafts made of lashed-together timbers around Land’s End through some of the stormiest waters of the British Isles? In 2000, as part of the millennium celebrations, a lottery grant was awarded to a group who intended to use Neolithic technology to bring a bluestone by land and sea from Wales to Stonehenge.
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The millennium bluestone was moved on wooden rollers and then prepared for embarkation, slung between two boats on the banks of Milford Haven. It didn’t even get out of the harbor. Four miles out, the stone slipped into the sea and had to be retrieved by divers and a crane. I think most archaeologists are fairly skeptical now about the likelihood of ocean-going bluestones. If about eighty finally arrived at Stonehenge, how many
didn’t
make it? Shouldn’t the bottom of Milford Haven be full of bluestones, the results of failed attempts to float them off successfully?

Another possibility, less often considered, is that the bluestones were moved overland for most of their journey. Anthropological studies of megalith-moving confirm that, in traditional societies, people go to great lengths to avoid having to cross water during the transportation of stones—it’s just much more difficult than moving them by land.
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In such societies labor is cheap (and there’s no OSHA oversight); in fact, at such events, the number of people who can be enticed to help pull the stone is an index of the organizer’s social status. In our own society, we’re often obsessed with working out the most labor-efficient means when we ponder how the Stonehenge stones could have been moved. Such ergonomic planning is unlikely to have cut much ice in Neolithic societies—the whole point was to have hordes of people involved, not to save labor.

Stone 68, a Stonehenge bluestone of spotted dolerite, has been carefully shaped and has a groove down one side.

If the bluestones were brought overland (with the exception of crossing the River Severn or its estuary), they could have been passed on from one community to the next in a relay involving thousands of people. As I’ve observed in Madagascar, the problem with moving and lifting megaliths is not in finding enough people but in having to cope with too many. Everybody wants to be involved, especially when there is free alcohol and fresh beef at the end of the day’s work. With fifty people on each
bluestone, there might have been a task force of four thousand stone movers if the stones were all brought from Preseli to Wessex in one go. With people dropping in and out as new teams took over at regular intervals, this could have involved an upper limit of as many as a hundred thousand people—that’s a figure possibly close to the total population of southern Britain at that time.
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Anyway, the subject of moving the bluestones from Wales to Salisbury Plain is perhaps the aspect of Stonehenge that most intrigues people. There have been all kinds of ingenious ideas. The conventional notion of moving stones on wooden rollers works well for bluestones but we mustn’t forget that the builders also had to move the much, much bigger sarsens from the Avebury area. It would probably have been impossible to use rollers for the larger sarsens, which must weigh upward of twenty tons: Such heavy weights would have caused any such rollers to sink into the ground; additional timber rails would have been needed to support the rollers and spread the weight. Derbyshire builder Gordon Pipes came up with an ingenious scheme of “rowing” the sarsens: Using this method, the stone sits on its cradle or sledge while lines of people on both sides use wooden poles as levers to lift the stone about 15 centimeters into the air and then forward the same distance.
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There is surely something to be learned from the solutions found by traditional societies that still move big stones by hand today. On the island of Sumba in Indonesia, the stone is placed on a wooden cradle and moved on wooden rollers pulled by more than two hundred men.
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The sponsor of the event stands on top of the stone, leading the chanting and singing that establishes a rhythm for the stone pullers. In Madagascar, Ramilisonina has taken part in many stone-pullings and emphasizes the importance of bedding the stone on its cradle in springy materials—shrubs and other vegetation—to act as shock absorbers.

The idea that the bluestones were brought from Wales by human muscle power is not accepted by everyone. As long ago as 1902, William Judd proposed that the bluestones might have been transported to Stonehenge by glaciers.
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Herbert Thomas disagreed profoundly with Judd’s suggestion, asking where there was evidence for glacial-drift deposits on Salisbury Plain, or for glaciation east of the Bristol Channel.
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In the 1970s, Geoff Kellaway identified glacial sequences deposited on
the east side of the Bristol Channel around Bristol and Bath, perhaps during the Anglian glaciation around 450,000 years ago.
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He also thought that there was an even more extensive glaciation across southern England, which extended from Cornwall as far as Sussex and the English Channel during the Saalian glaciation around 300,000 years ago. Kellaway didn’t receive much support for his ideas from other geologists but, between 1990 and 2002, he revived his ideas in a modified form.
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He now thought that the bluestones might have been moved during a glaciation in the Pliocene, 2.47 million years ago, carried southeastward toward Salisbury Plain in the ice of an ancient river whose surviving trace today is the Solent near Southampton.

There is some evidence of glaciation of southern England, probably in the Anglian period. Rocks picked up by glaciers and dropped far from their source are known as glacial erratics. The distribution of glacial erratics has been plotted over the years by the British Geological Survey and extends across eastern England but not as far west as Salisbury Plain. Rocks from the Scottish Midland Valley, north Wales, and northern England have ended up as far south as Hertfordshire and Buckinghamshire. In the 1970s, geomorphologist Christopher Green examined the pebbles of Wiltshire valleys and concluded that there was a complete lack of glacially derived material in these river gravels.
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No one has been able to find any trace of glaciation on or around Salisbury Plain. When I sought clarification of this point, my Sheffield colleague Chris Clark, professor of glaciology, explained that glaciers broadly do not flow uphill. A glacier flows in the direction of slope from the center of the ice sheet to its margin, so the ice can quite happily move up hills in the glacier’s path. However, when very close to the margin where the ice is thin and the surface slope low, a glacier would rather go around a hill than over it.

On the subject of ice, I receive countless emails about the possibility that the bluestones—and sarsens—were dragged to Stonehenge across frozen lakes, along frozen rivers and on specially prepared ice roads. The evidence for climate and temperatures in the third millennium BC shows that, when Stonehenge was built, temperatures were 1–2 degrees warmer than in later millennia; it was never cold enough for long enough for transport across ice to have been possible.
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Since Kellaway’s time, the glacial-movement hypothesis has been revived and reworked many times. Its chief proponents today are Olwen Williams-Thorpe, a geologist, and Brian John, a glaciologist, who have studied bluestones for more than two decades.
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They point to sound evidence for glaciation from the Isles of Scilly to south Wales and further north. John thinks that bluestone erratics could have been dumped south of Bristol in the area around Glastonbury, where perhaps some remain to be found, buried beneath the peat. Even if this hypothesis were correct, Neolithic people would have had to move the stones forty miles from Glastonbury, or anywhere else in the Severn valley, to Stonehenge.

Yet even this scenario is unlikely on geological grounds alone. Chris Clarke has just carried out a major study of the limits of all previous glaciations in Britain.
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He notes a distinct lack of any evidence that the ice advanced into southwest England at all. Even at the height of the last glaciation, around 27,000 years ago, the ice sheet seems not to have extended beyond Wales, let alone as far as the area around Bristol and Somerset. No glacier reached Salisbury Plain or even close to it.

The glacial-erratics argument appears to entail our accepting that no Neolithic person in their right mind would have dragged stones further than they had to. This line of reasoning proposes that the most likely Neolithic motivation for using the bluestones is purely pragmatic, that people simply searched for large stones in the closest possible proximity to Stonehenge. Searching over an ever-widening radius from Stonehenge, this argument goes, the Stonehenge builders would have located sarsens to the north and glacially erratic bluestones to the west.

The evidence to which Williams-Thorpe and John point in support of their theory and the questions raised are intriguing. Why are there so many different types of bluestone at Stonehenge? Williams-Thorpe has counted as many as thirteen “foreign” rocks, many still not identified as coming from Wales.
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She thinks it odd that there was no careful selection to ensure geological consistency. Why are there monoliths of soft, easily eroded stone, such as the Altar Stone? The harder stones would have been much better suited to long-distance human transport.

Williams-Thorpe also wonders why the bluestone chippings found in round barrows are found only in the soil of the mounds rather than as
valuable artifacts placed within the graves under these barrows. In other words, if the bluestone monoliths were worth bringing all the way from Wales, why weren’t their chippings treated with a bit more respect a thousand years later?

She has also analyzed axes and other prehistoric artifacts made of preselite or spotted dolerite.
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Although there are only a dozen of these (a very small number in comparison to the thousands of Neolithic stone axes exported from quarries such as Graig Lwyd in north Wales or Langdale in Cumbria), the Preseli-derived stone tools have a very unusual distribution. Some have been found in Wales, but in a wide distribution from Anglesey to the Forest of Dean. There is a concentration of four from Salisbury Plain, with three others from along the south coast between Devon and Hampshire. Might these seven southern English artifacts derive not from long-distance trade but from a local source of glacial erratics? It is certainly possible, but the problem with this theory is that no preselite artifacts have been found between Wales and Salisbury Plain: There are none from the English side of the River Severn, the very area where the bluestone erratics are supposed to have been deposited by the glaciers. Instead, the distribution of these spotted-dolerite tools is more suggestive of human transport. It is possible that there was a link between Preseli and Salisbury Plain that began before the building of Stonehenge, back in the Early Neolithic of the fourth millennium BC, when axes were definitely exchanged or traded over long distances all around Britain and Ireland.

Tim and Geoff’s excavation at Stonehenge in 2008 recovered a blank for a bluestone implement, and others have been found there by previous excavators. It is possible that Stonehenge, in its declining years toward the end of the third millennium BC, became a tool factory, producing objects that were traded within Wessex. After a thousand years, these once-revered standing stones perhaps became little more than useful raw material, miniature quarries for making maces and battleaxes. Of course, such items might have been perceived as imbued with special power—a Stonehenge-derived macehead could have trumped a macehead carved from another type of stone. But whether or not bluestone tools had special value, respect for the monoliths themselves was on the wane by the beginning of the Bronze Age.

No discussion of bluestones is complete without a brief account of the mysterious case of the Boles Barrow bluestone boulder. Boles Barrow is a long barrow at Heytesbury, about eleven miles west of Stonehenge. From its form and style, this barrow probably dates to before 3000 BC, most likely to somewhere within the period 3800–3400 BC. William Cunnington wrote in 1801 that, within a ridge of sarsen boulders (weighing between 13 and 90 kilograms) running down the middle of the barrow, he had found “the Blue hard Stone also, ye same to some of the upright Stones in ye inner Circle at Stonehenge.”
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He took away this stone and the sarsens to make a garden feature at his house.