Eby modern standards, John o’Groats to Wiltshire is a bit of a trek: almost 500 miles, 13 hours by car or a 10-day walk – and that’s without having a six-tonne block of stone in tow. So the revelation this week that Stonehenge’s altar stone came from the north-east of Scotland begs the question of how on earth this feat was accomplished over 4,000 years ago.
“When you’re trying to move something that weighs six tonnes over 750km, it’s an enormous undertaking,” says Prof Nick Pearce, a geologist at Aberystwyth University and co-author of the research.
Even from its previously assumed origin in Wales, moving the megalith seemed such a difficult task that some academics suggested that it was in Wiltshire through a natural glaciation process.
Pearce said: “There was a lobby which argued that the stones were transported with ice to the area nearby. Stonehenge and then picked up and used.” But this scenario rules out the revelation that the stone had a Scottish origin as the ice flow from the region was in a northerly direction. “From Orkney, I can’t see a way for the stone to take a trip on half a dozen glaciers in the right order to end up on Salisbury Plain.
There is also evidence that the rocks were ripped from the landscape rather than being serendipitous finds. “Based on our fieldwork in the southwest Wales it is likely that the stone was taken out, rather than just lying loose on the surface,” said Prof Richard Bevins, also from Aberystwyth. Archaeologists have previously found stone wedges and hammerstones in the Preseli area of Wales that appear to have been designed for such a task.
Bevins said: “The altar stone, which is a sandstone, has a natural parting plane, which can be mined in exactly the same way with rock wedges and hammer stones, allowing the extraction of a large sheet-like rock.”
The next job would have been to lift the stone off the ground, which is less difficult than it sounds, according to Julian Richards, an archaeologist and TV presenter. It is based on his own experience of lifting a 12-ton capstone from a Neolithic grave during a visit to Cornwall a few years ago. “I underestimated its weight, but we just got it off the ground with a series of wooden levers,” he said. “Lifting it is not a problem, but moving it is.”
From there, Richards speculates, the stone may have been strapped to a wooden sled and pulled along logs arranged like railroad eddies with ropes made from plant fibers. “You can make good ropes out of things like lime bark,” he said. “It produces very strong, long fibers that can be woven into ropes that will be able to move something of this kind of scale.”
Experts are divided on whether land or sea is a more likely option for the stone’s onward journey.
“My feeling is that it came overland and it may have taken a long time and not necessarily in one fell swoop,” says Heather Sebire, a senior curator at English Inheritance. “Getting places as quickly as possible is a modern concept – we are always in a hurry. Their mindset was probably very different. You can think of it as a pilgrimage.”
The terrain would have been challenging, Sebire said, but the idea that the entire British Isles were covered in dense forests is a myth. “Near Stonehenge it would have been open scrub with clumps of trees,” she said. “If they literally went from A to B, it could have been months or it could have taken years.”
Sebire is also affected by a lack of archaeological evidence for advanced Neolithic boats. “Experiments have been made to bring the equivalent of the bluestones on rafts across the Severn,” she said. “I’m afraid none of them have been successful. They sank.”
Richards is more enthusiastic about the possibility of an ocean voyage, based in part on a re-enactment experiment of his own in which 140 people tried to move a 40-ton block of concrete. “We didn’t move it very far. Actually, it’s quite difficult to get a team of people together and coordinate them.”
This may have played to the strengths of Neolithic communities, for whom teamwork would have been an inherent part of daily survival. “These people were used to moving large stones,” Richards said. “When you see people who are used to moving things, they make it look easy. We underestimate their inherent skill and experience.”
He estimates that 40 to 50 people might be needed to drag the altar stone, but questions whether even a strong, cohesive team would be able to carry it over hills and around mountains. And although no sophisticated vessels have been discovered, there is evidence for a trade in stone axes between the Alps and the Lake District, pottery in southern England that originated in Orkney and herds of cattle transported across the Channel. “This idea that everyone lived in small isolated groups is not right,” Richards said.
Conclusive evidence about the altar stone’s route may remain elusive, but experts agree that the journey is further evidence of the Neolithic builders’ ingenuity. “Those people were just the same as us,” Sebire said. “They were just as smart and enterprising and they had the brain power.”
