Let’s see what we’ve got. I can’t claim to know much more about the newest Stonehenge story than any other journalist. The discovery of a stone row at Durrington Walls was first announced a year ago, almost to the day. We were given little data then, however, and I seemed to be the only one who noticed! So what do we know now?
- What do they say they have found?
Evidence that there was once a row of up to 90 standing stones about 3km north-east of Stonehenge, west of the road between Amesbury and Durrington,. The stones, probably local sarsens, ran for at least 330m. At the east end the row stops short of the line of a modern road, and apparently does not continue beyond; at the west end it continues to the edge of the survey area, so may extend further there.
At the eastern end up to 30 of these stones (the largest of which is 4.5m x 1.5m x 1m) are still there, having been pushed over and buried beneath the bank of the Durrington Walls henge. Elsewhere “the stones are fragmentary or represented by massive foundation pits”.
The row could be contemporary with the sarsens at Stonehenge, or be earlier in date.
This row followed a curving natural depression to the north, apparently artificially accentuated by a chalk-cut scarp. The scarp and stones delineated “a C-shaped ‘arena’ … [which] may have surrounded traces of springs and a dry valley leading from there into the Avon”, close by to the east.
- What is their evidence?
The key evidence for this comes from “a cutting-edge geophysical and remote sensing survey at an unprecedented scale and resolution”. The survey began in July 2010, and (I gather from Nick Snashall, National Trust archaeologist) was concluded two weeks ago at Durrington Walls, after spending a total of about 120 days in the field. Techniques employed include magnetometry, ground-penetrating radar, electromagnetic induction, earth resistance survey and terrestrial 3D laser scanning.
This is the survey that caused much interest on TV last year, and earlier in the press in 2011: the Stonehenge Hidden Landscapes Project, conducted by the Universities of Birmingham and Bradford, and the Ludwig Boltzmann Institute for Ayrchaeological Prospection. The listed technologies refer to the entire survey. Images of Durrington Walls are attributed to ground penetrating radar (showing the whole stone row), electrical resistivity tomography (showing a buried stone) and electro-magnetic induction (showing landscape topography). The images are impressive, but not much detail has been released.
- How do they know the features are stones?
On the evidence we have been given, the geophysical evidence for a row of large features is compelling. Less certain is what those features are, though again they seem to have evidence that suggests something solid is underground, and stone would be an obvious candidate.
They say the stones are probably sarsen for two reasons. First, there is a lone sarsen stone still on the surface in a field across the road, known as the Cuckoo Stone. Secondly, anything up to 4.5m long is just too big to be the other type of Stonehenge megalith, bluestone. They are joining up dots that are quite a long way apart, so really this is an open question.
- How do they know how old the row of stones is?
The argument for the age of the row depends on evidence that the stones are buried beneath the henge bank. The digging of the ditch that threw up the original bank is quite loosely dated to around 2500BC. So if the stones were buried when the bank was first thrown up, they must have been lowered around or before 2500BC. The sarsen circle at Stonehenge is dated to about the same time.
We have not been shown evidence for why they think the stones are buried beneath the bank (rather than, for example, buried down through the bank), though we might expect that to show in GPR plots.
- What else might they be?
Rows of large pits – often referred to as pit alignments, of unknown purpose – are not uncommon in prehistoric Britain, dating mostly between the early bronze age and iron age; so not as old as Stonehenge or Durrington Walls.
The area has been close to active military works since before the first world war, so an unknown military structure is not impossible. There seems to be no evidence for that, however, and old maps show nothing anywhere near the alignment.
[Next two paragraphs added 11am September 8]
Another possibility is that they might be something natural. Could they indeed be sarsens, but a geomorphological rather than an artificial feature (with the pits where they had been dug out)? That would be rather neat, a local source for the big stones at Stonehenge, much discussed but hitherto lacking in real evidence.
The way the line more or less follows the contour of the valley edge is perhaps suggestive, but this is not how sarsens are usually found: here, for example, we’d expect them to be in the valley bottom rather than up on the side, and more scattered than linear. So perhaps an in situ chalk formation, following the line of the strata and falling down into the rock from the near-surface exposure? Could those “stones” be some kind of massive nodular formation in the chalk? That would seem to go beyond what we know about chalk. But if they are megaliths, that does the same for archaeology. So it would be useful to hear from scientists who know about the chalk.
- Will the history of Stonehenge have to be rewritten?
There’s no denying they’ve found something, and any explanation that does not involve the long history of Stonehenge looks like special pleading. This is a genuine challenge to how we think about these sites, and potentially a major discovery and a stunning achievement for the research team.
Without excavation, however, we will never get to the bottom of what it is they have found – what the pits are, what the solid things are, and how old they are.
But for now, this is how they think it looked:
All illustrations in this post are from the Stonehenge Hidden Landscapes Project