I found this remarkably perceptive article by Aubrey Burl on the HistoryBookshop.com web site. The date seems to be 2001. It's a timely reminder that there ARE (and were, a decade ago) some archaeologists who are prepared to take geomorphology and geology seriously....
Stonehenge: How did the stones get there?
Aubrey Burl explains how the myth of the stones transported from south Wales to Salisbury Plain arose and why it is wrong
History is full of enjoyable myths but Stonehenge has too many. They mutate. Hardly had modern scholars got rid of the pre-Roman druids than those soothsayers reappeared in the guise of 3rd-millennium BCE astronomer-priests who are said to have designed the great circle as a celestial computer for the prediction of eclipses.
There are other common fallacies. The Greek explorer, Pytheas of Marseilles, who provided the first written account of Britain when he visited the islands c.300 BCE, is sometimes said to have visited Stonehenge. In fact, he landed near the splendid circle of Callanish in the Outer Hebrides 500 miles to the north. Just as mistakenly, Stonehenge is described as a British stone circle though it is not this at all, but rather an imitation in stone of a lintelled timber ring, with architectural influences from Brittany.
Perhaps the most persistent of these myths is that men ferried scores of enchanted Welsh stones hundreds of miles. Returning across the Irish Sea from the Wicklow mountains to their home in southern Britain some time after 3000 BCE, a group of gold- and copper-prospectors are said to have steered towards the landmark of the Preseli mountain range in south-west Wales. Regarding the Preselis as magical and their bluestones life-enhancing, the crews felt compelled to plunder them one by one for an intended megalithic sanctuary on Salisbury Plain. The romance has been repeated so many times in so many books that it has almost become fact.
But there is no substance to the story. The early third millennium BCE, when the great monument of Stonehenge was begun, was a pre-metal age which had little contact between Wales and Ireland. That came only with the discovery of Irish copper ores around 2500 BCE. Even then, there is no evidence for prospectors from mainland Britain visiting Ireland. What Irish gold or copper did reach Bronze-Age Wessex probably arrived in the form of ready-made axes and lunulae manufactured in Ireland and carried overseas by Irish traders.
The story of the transportation of the stones from Preseli is less than eighty years old. There is an alternative possible explanation, namely that glaciation was responsible for the appearance of the stones on Salisbury Plain. This is often discounted as many geologists argue that there is no proof of Pleistocene glaciation (from the era of the last Ice Age, which ended around 8000 BCE) on Salisbury Plain, and therefore there was no glaciation there at all. However, Geoffrey Kellaway, who in 1971 was one of the first to support the idea of glaciation, suggested in 1991 that the ice ages of the much earlier Pliocene Epoch (5.4 million to 1.6 million years ago) provided a more likely candidate for the event that transported the stones to the region.
Stonehenge consists of two kinds of stone: sarsen (Tertiary sandstone) and bluestone (various grades of dolerite, an igneous rock and other varieties of stone). The massive vertical pillars that one thinks of as archetypically Stonehenge are sarsens that originate from the Marlborough Downs eighteen miles to the north. There has been little controversy about them. As long ago as the seventeenth century the architect Inigo Jones (1573-1652) wrote, in a book published in 1655, the same kind of Stone whereof this Antiquity consists, may be found, especially about Aibury in North-Wiltshire, not many miles distant from it, where are not only quarries of the like stone, but also stones of far greater dimensions then any at Stonehenge, may be had.
He said nothing about the properties or source of the smaller bluestones. Perceptively, though, he did mock at a myth. 'For, as for that ridiculous Fable, of Merlins transporting the stones out of Ireland by Magick, it is an idle conceit'.
The 'ridiculous Fable' points to a geological fact, though an archaeological mistake. Unlike the sarsens, the source of the bluestones remained unknown for centuries until in 1923 the geologist H.H. Thomas deduced that the source was Carn Meini, 'the mound of stones', in the Preseli Mountains of Pembrokeshire. This immediately raised the question of how they made their journey from there to Salisbury Plain. The following year E.H. Stone remembered that Geoffrey of Monmouth's chronicle, more hysteria than history, had claimed in the twelfth century that Merlin had brought the stones of Stonehenge from Ireland. This, Stone speculated, was perhaps a half-remembered saga of Britain's first metal-workers returning from their search for ores in the Wicklows, using the Preselis as a landmark and carrying off boatloads of potent bluestones. But it was a conclusion based on a misunderstanding of Geoffrey of Monmouth. It was wrong about the type of stone and wrong about the prospectors.
In his History of the Kings of Britain, Geoffrey recorded that the Saxon leader Hengist of the fifth century AD treacherously slaughtered hundreds of British nobles at Salisbury. Their affronted war-leader, Aurelius Ambrosius, ordered a memorial to be erected on the site of the massacre. He sent for Merlin who advised, "If you want to grace the burial-place of these men with some lasting monument send for the Giant's Ring which is on Mount Killaurus in Ireland … The stones are enormous, and there is no one alive strong enough to move them". A British contingent went to Ireland but were unable to shift the pillars. Merlin laughed and "dismantled the stones more easily than you could ever believe" and erected them in a circle around the burial-place on Salisbury Plain.
It is a fable unique to Geoffrey. Earlier the same century, Henry of Huntingdon had remarked of Stonehenge, 'no one has been able to discover by what mechanism such vast masses of stone were elevated, nor for what purpose they were designed'. He did not mention Merlin, nor Wales. Three hundred years earlier the Welsh monk Nennius had written of the massacre but not of Merlin, Wales or Stonehenge.
Geoffrey, although probably a Welshman himself, said nothing about bluestones, nor the Preselis, nor even Wales. He did, though, emphasise that the stones were gigantic and beyond mortal strength, which surely suggests, even to the most sceptical reader, that he was referring to the sarsens - which are up to 30 feet long and weigh twenty tons or more - rather than the much smaller and five-times lighter bluestones. He may even have been unaware of them. Nor are they shown in a mid-fourteenth-century manuscript showing Merlin at work at Stonehenge.
Geoffrey's garbled report can be explained. Writing in the late seventeenth century the antiquarian John Aubrey remembered that, "Mr Gethin of the Middle Temple London, told me, that at Killian-hill (or a name like it) in Ireland, is a monument of Stones like those at Stone-heng; and from whence the old Tradition is that Merlin brought them to Stone-heng by Conjuration". He added in Latin that the pillars were "located on the plain, not far from Naas" in Co. Kildare. Some such menhirs do still exist, enormous grey, granite columns like Craddockstown West, 14.5ft high, Punchestown 17.5ft, and the 21ft high Longstone Rath. They were not in fact sarsens, but to the clerics travelling from England to St Brigid's Abbey in Kildare they did resemble them and seemed to be the remnants of a gigantic Irish ring that had been a quarry for the massive circle of Stonehenge. Merlin had carried the pillars away on his back, not stopping at the Preselis on his way.
In 1185, fifty years after Geoffrey's History, the Welsh cleric Giraldus Cambrensis saw the monstrous Irish menhirs on his way to visit the Kildare abbey and its magnificent illustrated manuscript, "'that wonderful book … so delicate and subtle". He was astonished by the size of the stones and wondered how they "were ever brought together"; it is obvious that it was their similarity to the Stonehenge sarsens, not the bluestones, that he and Geoffrey had in mind.
There was a dilemma. Geoffrey had the two ends of the story but lacked ways of bridging the 250 miles of land, sea and mountain between Kildare and Salisbury Plain. Aware that humans were incapable of freighting such huge pillars, the medieval chronicler turned to the equally acceptable superhuman. He invoked Merlin - the sixth-century seer Myrddin, already popular in Welsh legend and poetry - and it was that wizard who dismantled the stones and had them brought to Britain.
Once it is realised that Geoffrey was writing about sarsens being transported from Ireland, the farrago about talismanic bluestones from the Preselis is discredited. There are no sarsens on the Preselis. The Irish links with Stonehenge had nothing to do with the dolerite of the Preselis but everything to do with the mineralogical ignorance of medieval English visitors. The megalithic "epic" is merely wishful thinking.
Although the bluestones may have originated in the Preselis, the notion that humans moved them to Stonehenge is confronted by many archaeological difficulties. Transporting the bluestones from Wales to Wessex would have been a form of seafaring suicide. Metal prospectors, even in the third millennium, could quite feasibly have made such a journey with a manageable cargo of ores, travelling in easily-beached canoes, but in contrast the endeavours of crews attempting to manoeuvre a heavily-laden, clumsy raft along the seas of the Welsh coast would have been perilous in the extreme.
On a floating platform without sails, with propulsion dependent on paddles and poles, with little control over steering, and affected by every capricious current of the Bristol Channel, the crews would have faced the vicissitudes of weather and a recurring series of threats: strong tides, undertows, lethal sandbanks. Added to these difficulties is the fact that natives of land-locked Salisbury Plain are unlikely to have been experienced seafarers. To cope with the treacheries of the southern Welsh coastline and the swirling waves of the Irish Sea they would have needed the assistance of local fishermen knowledgeable about the currents and the signs of suitable weather.
Even at the end of the sea voyage further challenges remained. When the Bristol Avon had been reached the sea-going raft would have had to be abandoned and the stone transferred to a vessel more suited to narrow and winding rivers. Further on it would have had to be unloaded for an overland portage of several miles up exhausting slopes until the cargo could be lashed to a third craft for an up-river crawl along the twisting River Wylye - the 'tricky or treacherous stream'(according to the authors of The Place-Names of Wiltshire, 1970) - then northwards up the Christchurch Avon towards Salisbury Plain and Stonehenge. This unparalleled undertaking would have had to be repeated almost eighty times, over a period of many decades.
The demands of such an enterprise were underlined by the attempt by a group led by Phil Bowen and given lottery money last year to reproduce the journey. As a scientific experiment it was sadly flawed. From the beginning the project was compromised by a series of economies, precautions and shortcuts. A bluestone one ton lighter than any at Stonehenge was chosen. It was dragged on a sledge from the Preselis, though not over rough ground but along mesh-covered roads. A lorry was used to take the load over difficult slopes. At the coast the stone was lashed on a cradle between two lightweight curraghs or coracles instead of being laden onto a sensible, well-constructed raft. At the end of the intended voyage the team planned to avoid the challenge of rivers and an arduous cross-country haul by floating the cargo on a barge along the Kennet & Avon canal - not an option that would have been open to the people who built Stonehenge. Yet even with these spurious adaptations the mission ended abruptly just four miles out to sea when the stone slipped from its lashings, fell into the water and sank 60 feet to the muddy bottom of Freshwater Bay, Pembrokeshire, with its sharp currents.
The 'reconstruction' was an ill-researched, ill-prepared fiasco. But its failure does emphasise how difficult and dangerous a genuine adventure would have been. Whatever the method by which the stones arrived on Salisbury Plain, they were apparently set up in about 2800-2700 BCE inside a much older earthwork, in either an unfinished concentric circle or an incomplete horseshoe open to the southwest A century or so later (c.2500 BCE) the great sarsen circle was constructed, and the bluestones were dragged from their holes (called the Q and R Holes, after John Aubrey's Quaere) only to be returned some centuries later to form an irregular circle and an elegant horseshoe inside the towering sarsens. Some remain today in these positions. In 1983 a systematic archaeological search of the Preselis was undertaken to look for signs that the Stonehenge bluestones might have been quarried or removed. It concluded: "The field survey has not yet produced any direct evidence that the Stonehenge bluestones were quarried or collected from the Preseli Mountains in the third or second millennium BC". Yet the indisputable fact remains that stones originating in outcrops found in southwest Wales were used in an early phase of the building of Stonehenge.
If the people building the monument indeed brought them there, it was probably from close by, a few miles from Stonehenge where there was a convenient glacial deposit of the only stones among the chalk and flint of Salisbury Plain. Of the more than 1,300 stone circles in Britain, Ireland and Brittany, not one has stones brought from more than six miles away. There is no reason for Stonehenge to be an exception now that Preselis' 'magic mountain' has been shown to be irrelevant. To answer 'Stonehenge is unique' is a convenient evasion. Those who argue for the human-transportation thesis rarely explain why men would have chosen to transport crude blocks all that distance without first removing unwanted, heavy protrusions from the stones. Professor W. Judd asked this question in 1903, twenty years before H.H. Thomas: "The old tradition concerning Stonehenge [is] that it consisted of a circle of 'bluestones' which had acquired a certain sanctity in a distant locality, and had been transported from the original home of the tribe. If so, the stones, brought from so far away, would have been reduced to something like half their bulk … Is it conceivable that these skilful builders would have transported such blocks of stone in their rough state over mountains, hills and rivers (and possible over seas) in order to shape them at the point of erection?"
Yet whatever 'dressing' the stones received, occurred when they reached Stonehenge. The mass of bluestone chippings found there, 'the Stonehenge floor', testifies to that. In contrast, Judd continues, those who hauled the sarsens 'would appear to have left only the final dressing to be done after their transport', in spite of moving them a much shorter distance. Thomas attempted to answer this by suggesting that the chippings found on the site were the result of an original unshaped bluestone setting being smoothed later for a reconstructed ring, a conjecture that leaves Judd's criticism intact. Logic, though, insists that it would have made sense to lighten a stone at source, and this would also have made it easier to secure the half-shaped block for its long, perhaps stormy, journey.
As the 'magic mountains' in which the stones were found, the Preselis are doubly discounted: firstly by the Merlin story, and secondly because there was plenty of suitable stone much closer to Stonehenge. It was available to the north on the Marlborough Downs, to the south in Dorset and to the west in the Mendips, all less than a sixth of the distance to southwest Wales.
Meanwhile, about twelve miles west of Stonehenge in the vicinity of the Boles earthen long barrow near Warminster, there was a litter of glacially shifted stones from the Preselis. This has been known since 1801, when William Cunnington excavated the barrow and found a large bluestone buried deeply within it. So firmly accepted is the legend of human transportation that Cunnington's discovery is ignored or dismissed for a variety of reasons: it was the wrong stone; it was not a bluestone; it was deliberately concealed in the mound 4,000 years later by murderous Saxons. None is credible.
By the time that Stonehenge was built, men possessed a centuries-old expertise in recognising the best stone for their axes, and exploited sources as far apart as Land's End, the Lake District and north-eastern Ireland, while rejecting unsuitable stone such as sarsen or slate. It is inconceivable that for their first stone circle at Stonehenge, a prestigious monument that was to endure for lifetimes, the builders would casually accept not fine-grained durable stone but third-rate material such as tuffs, rhyolites and calcareous and volcanic ash, when excellent dolerite blocks were plentiful on the slopes of Carn Meini. Some of the Stonehenge bluestones were so imperfect that they weathered into stumps in a few years. Rather than envisaging the transportation of such rubbish these distances, it is probable that there was a muddle of good, bad and ugly stone within a few miles of Stonehenge, brought there naturally some millions of years earlier.
Believers in human work-gangs assert that the stones were taken from the Preselis because these stones were believed to have special powers. Yet those superstitious men searching for health-giving slabs were so incompetent that they also apparently chose the Altar Stone that now lies at the heart of Stonehenge. This also originated in south Wales, though not in the Preselis themselves but from about twenty miles away. It was not bluestone but sandstone of which an abundance was already available in the sarsens of the Marlborough Downs. It had no special shape, bore no arcane carvings. Yet this nondescript seven-ton slab was apparently selected and transported on the hazardous journey. More feasibly, surely, this stone simply lay among a clutter of others on Salisbury Plain.
The theory for the transportation of the stones by glaciation is not without supporting evidence. There are unsubstantiated reports of bluestones having been found on Salisbury Plain not far from Stonehenge, at Seend and at Edington, and there is proof of at least one substantial dolerite deep in the mound of Boles long barrow, a Neolithic burial-place blocked up and abandoned centuries before the ring was contemplated. William Cunnington, the antiquarian and fair geologist who found it in 1801, also wrote something pertinent, implying that he had recognised not only the bluestone but other types of Preseli stone in the barrow: "a great variety of the stones found in an oblong barrow near this place that are of the same kind with several of those at Stonehenge."
Other than the medley of 'bluestones', there is no variety at Stonehenge, just homogeneous sarsen. One wonders if Cunnington had also recognised rhyolites and tuffs in the barrow, neither of which are local to Salisbury Plain. Nor were the true bluestones, plain and spotted dolerite, ever thought to have special powers. There are stone circles around the Preselis, but they are built, like all circles, of stones in the immediate locality, dolerite being just one of a mixture of tuffs, rhyolites, sandstones and volcanic ashes. Only Gors-fawr, in the immediate vicinity of Carn Meini, was composed solely of dolerite and its moorland is strewn with the slabs.
To this long list of objections to the notion that human transportation accounts for the presence of the bluestones must be added the identity of the so-called 'prospectors'. Until recently they were believed to be the people known as Beaker Folk. The earliest peoples given this name were immigrants from the European mainland in the later third millennium who settled warily on Salisbury Plain, well away from Stonehenge and its natives. But their successors, users of the attractive sealing-wax red Wessex/Middle Rhine beakers, whence they take their name, were wealthy leaders with copper daggers and gold cruciform discs and button-caps. These people might conceivably have gone to the Preselis.
The authority on British beakers, David Clarke, thought so in 1970 when he wrote: It is at least possible that these powerful chieftains directing the trade and exploitation of Southern Ireland, by way of the Bristol Channel and South Welsh coast, may have had the Prescelly [sic] stones brought along the copper/gold route to Wiltshire and Stonehenge, remembering that Prescelly Top, at 1760 feet [537m], is every sailor's landmark on the shortest crossing from the gold bearing hills of Wexford - a veritable Welsh Olympus. When Clarke was writing in 1970, Stonehenge was still thought to have been an Early Bronze Age artefact, built about 2000 BCE. The makers of the elegant Wessex/Middle Rhine beakers were seen as having arrived in Britain around 2200-2100 BCE, a century or two before the impressive circle was erected.
Recent studies are in agreement with Clarke's chronology for the Beaker Folk if not for Stonehenge itself, accepting a date of 2300-2100 BCE for the beakers. Recent radiocarbon dates from Stonehenge, though, show that the sequence of its three megalithic phases was: (1) on or before 2700 BCE, the first bluestone setting was erected; (2) the bluestones were removed from the Q and R Holes and the imposing sarsen lintelled circle and trilithons were constructed around 2500 BCE; (3) finally, about 2250 BCE, the bluestones were restored as a circle and horseshoe inside the sarsens.
The fact that some of the stoneholes of the sarsens of 2500 BCE cut through the Q and R pits, demonstrates that the latter must be earlier than this date. This kills the notion of the Beaker Folk having brought the bluestones to the site. The 'prospectors' were as many as seven centuries years too late.
Pre-Beaker prospectors did not go to Ireland; they had no need. Theirs was not the time of gold or copper and there was already good stone for axes in Britain. Archeologically, there is no evidence of anyone who could have fetched the bluestones.
It has never been explained why the Q and R Holes project was left incomplete. The simplest explanation is that people found, to their dismay, that there were insufficient half-buried glacial dolerites, rhyolites, sandstones and tuffs for their ambitious Stonehenge project. In frustration they abandoned the scheme and turned to a more imposing source, the sarsens of the Marlborough Downs. Those massive stones were hauled laboriously over dry land by natives of Salisbury Plain who really did exist.