How Neolithic people transported so many enormous boulders from Wales to Stonehenge is one of archaeology’s most enduring mysteries.
However, a new study of a ‘lost’ boulder removed from the Stonehenge site more than 90 years ago shows that humans may not have moved the stones at all.
Dr. Brian John, a retired geology lecturer at the University of Durham, claims that this bluestone boulder shows signs of having been moved by glacial ice.
This would undermine the common theory that the bluestone was quarried in the Preseli Hills of south-west Wales and transported by hand to the Salisbury Plain.
Speaking to MailOnline, Dr. John: ‘I think it’s extremely important because it supports the assumption I’ve had for years that these are not transported by humans.’
A new assessment of a ‘lost’ boulder from Stonehenge suggests the site’s massive stones may not have been transported by humans
The Newall Boulder (pictured) was almost forgotten for more than 90 years, but research shows it may have been transported to Stonehenge from Wales by ice
In addition to the tall Sarsen stones that define Stonehenge’s distinctive appearance, the site is also home to approximately 80 smaller bluestones.
It is generally agreed that these stones came from the Preseli Hills in south-west Wales, but how they ended up at Stonehenge is often debated.
The argument of Dr. John focuses on an analysis of a bluestone boulder the size of a human skull known as the Newall Stone.
This rock was first excavated in 1924 by geologists Colonel Hawley and Robert Newall.
Hawley initially thought the stone was just a piece of trash and wanted to throw it away rather than analyze it.
However, Newall rescued the stone from the rubbish dump and placed it in a cardboard box in his attic, alongside a number of other finds from the site.
Stonehenge is a prehistoric megalithic structure on the Salisbury Plain in Wiltshire, England, two miles west of Amesbury
Dr. Brian John, a retired geology lecturer at the University of Durham, claims that this bluestone boulder shows signs that it was moved by glacial ice
The boulder remained there until Newall transferred it to the Salisbury Museum shortly before he died in 1976.
There was a brief interest in the boulder around 1977, but then it was put back into storage and forgotten for another 46 years.
In 2022, Dr. However, John made a reference to the boulder and asked museum director Adrian Green if it was still in storage.
Finding this to be the case, he was given permission to examine it and carefully examine its surface features.
Through detailed analysis of the boulder’s surface, Dr. John a series of markers that indicate glacial transport rather than human transport.
‘Glacially transported boulders often have facets,’ explains Dr John.
“That means they have a number of different faces that are angled to each other and that actually indicate where a boulder has been scoured or, actually, sanded.”
As boulders move with a glacier, they are tilted back and forth, creating distinct flat surfaces with rounded edges, much like Newall Rock.
The findings suggest that the approximately 80 bluestone boulders at Stonehenge were all carried to the site by ice and not by Neolithic builders.
In addition, the boulder exhibits a series of scratches and small fractures called striations and chatter marks, which are often caused by glacial transport.
And while the Newall Boulder isn’t exactly the same type of rock as the other bluestones, Dr. John says it’s exactly what his theory would predict.
He says: ‘Popular articles often claim that the bluestones are all made of mottled dolerite, this type of igneous rock that we find on the Preseli Hills, but there are actually about thirty different types of rock.
“That enormous variety of rock types is absolutely typical of the way ice moves across the terrain and picks up boulders from here and everywhere.”
Dr. John says these bluestones (photo) are far too weathered and rough to be mined and transported
Dr. John suggests that this provides compelling evidence that the Newall boulder and all the smaller bluestone boulders at Stonehenge were moved by a glacier.
His claims land him in the middle of one of Stonehenge’s controversial debates.
The idea of the stones being transported to the Salisbury Plain began in 1923 with geologist Herbert Henry Thomas.
Although Thomas was spectacularly wrong about almost everything, the theory of human transportation is still extremely popular.
The bluestone boulders may have been carried from Wales to the Salisbury Plain by a combination of Welsh and Irish ice
A team of researchers led by Professor Mike Parker Pearson of UCL were one of the most active proponents of this theory, arguing that the stones were moved over land.
Recently, Professor Pearson and his team even claimed to have found evidence identifying the Stonehenge bluestone quarry, dating back to 3000 BC.
Dr. However, John now says his discovery should “open the debate” to consideration of other theories.
He says: ‘Herbert Thomas thought that because transport across the glaciers was impossible, they must have been carried by people.
‘That’s part of our national myth now, because people haven’t seriously questioned it before; it’s just accepted as the truth.’
This map shows the variety of stones present in South West Wales. Dr. John says the variety of bluestone types is similar to the way a glacier would collect rocks from many different places
Rather than the orderly and rather deliberate construction project we sometimes imagine Stonehenge to be, Dr. John says, “I think it’s always been a bit of a mess.”
He argues that the Neolithic builders simply used the stones they had in their immediate vicinity, rearranging and moving the smaller bluestones as necessary.
And when they eventually had to travel too far to collect more stones, the project was simply abandoned in the state we find it in today.
“It was a Neolithic cost-benefit analysis that ultimately the cost of obtaining the stones outweighed the benefits derived from them,” he says.
This suggestion could overturn the prevailing theory that the Stonehenge bluestones (pictured and numbered) were transported overland by humans
The ultimate test for his theory, however, would be cosmogenic dating – a test to determine how long rocks have been exposed to the surface by measuring their exposure to cosmic rays.
If Dr. John is right, the deeply weathered surface of the rocks would have been exposed to the elements for hundreds of thousands of years.
Alternatively, if the stones had been mined, they would have only been exposed to cosmic rays for about 3,000 to 5,000 years.
Although the debate over the origins of the stones is still very much alive, Dr John believes the evidence of weathering will remain strong.
He concludes: ‘I am confident that if some university can do its job and actually make it happen, these rocks may have been subject to cosmogenic bombardment from the atmosphere for hundreds of thousands of years.
“That would turn the idea of quarries on its head once and for all.”