Sources of Stonehenge’s Stones
by Mike Parker Pearson
Sources of Stonehenge’s famous bluestones lie close to Brynberian. The bluestones are the smaller stones standing at Stonehenge, 140 miles away. They are a variety of rock types: dolerite, rhyolite, volcanics and sandstone. Geologists have identified the impressive outcrop of Craig Rhos-y-felin in Brynberian as the source of one of the four types of rhyolite at Stonehenge. They have also matched spotted dolerite pillars at Stonehenge with the outcrop of Carn Goedog further upstream on the north flank of the Preseli hills.
Archaeological digs at the foot of each outcrop uncovered evidence that bluestone pillars were quarried in the Neolithic period 5,000 years ago. Stone tools included wedges to open the joints between the natural pillars. An artificial stone platform was constructed at the foot of each outcrop, from which pillars could be lowered, presumably onto wooden sledges. At Craig Rhos-y-felin a trackway led northwards from the platform along the riverbank. Burnt shells of hazelnuts, probably food remains left by the quarry-workers, provided some of the samples for radiocarbon dating.
Some of the bluestones may have formed a stone circle here in Brynberian. On the hill of Waun Mawn, four large stones are all that is left of a Neolithic stone circle which was put up around 3000 BC. Archaeological excavations have revealed that standing stones were removed from the emptied sockets, probably in the Neolithic period. With its midsummer solstice-facing entrance, this former stone circle may have been the site of the original Stonehenge – later erected on Salisbury Plain in Wiltshire.
Brynberian sits within a remarkable prehistoric landscape in North Pembrokeshire that includes Neolithic tombs and enclosures as well as the incomplete stone circle at Waun Mawn. The tombs, built in 3800-3600 BC, are known as cromlechau or portal dolmens and were constructed with upright pillars supporting a capstone. The most famous is Pentre Ifan, just a mile north of Brynberian. To the south, perched on top of a hill above the crossroads at Rosebush, is a causewayed enclosure, also built around 3700-3600 BC. This was probably a gathering place where people came to feast and party. Causewayed enclosures are found in England and in east Wales but this is the only one known so far west. This was an important area in the centuries before Stonehenge.
Stones for Stonehenge
The largest stones at Stonehenge are sarsens, a form of silcrete or sandstone. Whilst they came from just 15 miles north of Stonehenge, the smaller bluestones originated in Wales, mostly from the Brynberian area.
Of the different types of bluestone at Stonehenge, the most famous are the pillars of spotted dolerite, a blue-green igneous rock with white spots. This distinctive stone is found in Britain only in the Preseli hills. The chemical composition of spotted dolerite pillars at Stonehenge can be matched with the outcrop of Carn Goedog, on the north flank of the Preseli hills, south of Brynberian. Although the larger outcrop of Carn Menyn/Carn Meini had long been thought to be a source for Stonehenge, its rocks have a slightly different composition.
Stonehenge’s three bluestones of dolerite without spots can be sourced to the Preseli ridge, notably at Cerrigmarchogion, 2 miles south of Brynberian. Two of the sandstone bluestones also come from the sedimentary deposits of the North Pembrokeshire region. The Altar Stone, a 5m-long sandstone block now lying in the centre of Stonehenge, originated further east in the Crickhowell-Abergavenny area.
A handful of Stonehenge’s bluestones are of rhyolite, an igneous rock formed as solidified sheet lava. At least one of these was quarried from the outcrop of Craig Rhos-y-felin in the valley a mile to the west of Brynberian. Like the stones at Carn Goedog, the rock at Craig Rhos-y-felin has formed natural pillars that are easy to detach with simple technology. Thanks to a remarkable feature in the original cooling of the lava, the microscopic structure of the rhyolite varies around the outcrop at Craig Rhos-y-felin. Rhyolite from Stonehenge can be matched to just one spot. Here, a gap in the rock face is evidence that a pillar has been removed.
The megalith quarries
At Craig Rhos-y-felin Neolithic quarry-workers constructed a level platform of stones and sediment at the foot of the outcrop. This platform was supported by a low revetment wall of rough stones, providing a 1m-high drop down to the valley floor. This presumably acted as a loading bay so that a monolith could be carefully lowered from the platform and onto a sledge to take the stone away. In the soft sediments at the foot of the platform, a long hollow was left from moving one or more monoliths away from the quarry. The stone-movers left behind their stone tools as well as burnt shells of hazelnuts and other pieces of burnt wood which have been radiocarbon-dated to reveal that this happened just before and around 3000 BC. Archaeologists have established that the bluestones were first erected at Stonehenge around or shortly after 3000 BC.
People came back to quarry more monoliths at Craig Rhos-y-felin a thousand years later in the Bronze Age. They constructed a second platform, further from the valley bottom, and prepared a large monolith for transport. It still lies where it was left, perhaps abandoned because it had developed a crack across its middle.
The outcrop of Carn Goedog is surrounded by scree on all but its south side where quarry-workers have extracted stone in the past. The last time this was done was around 200 years ago when the outcrop was quarried for building stone, breaking the thin pillars into small blocks. Fortunately they left untouched an area where much more ancient quarrying had taken place. Here the recesses and gaps in the rock face reveal where whole pillars were pulled out and removed. With only crude stone tools such as wedges and hammerstones, they must have prised open the joints between each natural pillar, levered them out, and lowered them onto the artificial stone platform below. Fragments of burnt wood within the platform have been dated to the same time as those at Craig Rhos-y-felin, just before and around 3000 BC. They must also have used ropes and tools of wood, bone and antler but the soil conditions at both sites do not allow such materials to survive.
Where did the bluestones go?
On the hill of Waun Mawn, a mile southwest of Brynberian, four large stones are all that is left of a large and incomplete Neolithic stone circle. Archaeologists have found sockets for another six standing stones. Together with the four survivors, these would have been part of a circle with a diameter of 110m. Waun Mawn would have been the third largest stone circle in Britain after Avebury in Wiltshire and Stanton Drew in Somerset. It is also the same diameter as the ditch that encloses Stonehenge. An entrance to the stone circle faces towards midsummer sunrise, the same direction as at Stonehenge. The circle at Waun Mawn has been dated to 3400-3000 BC by radiocarbon and luminescence dating (measuring the remnant energy in quartz grains since last exposed to light). It is more difficult to date the removal of the standing stones but this occurred most probably in the Neolithic.
Stone chippings left in one of Waun Mawn’s emptied sockets reveal that an unspotted dolerite pillar originally stood there, its imprint matching the base of one of the pillars (Stone 62) now standing at Stonehenge.
Archaeologists estimate that about 80 bluestones were taken to Stonehenge. Waun Mawn may have provided some but probably not all of them. Others may have come directly from the megalith quarries, and yet more may have been taken from other stone circles waiting to be discovered in the Brynberian area.
How were the bluestones moved?
Although the bluestones weighed less than 3 tons each, the stone-draggers faced a journey of 140 miles as the crow flies to reach Salisbury Plain. We know from reports of stone-moving among megalith-builders of modern times in different parts of the world that stones of this size can be transported effectively on wooden sledges slid along timber ‘rails’ (more effective than timber rollers which tend to jam). A large team of hundreds of rope-pullers, path-clearers and rail-movers can drag a 2-ton monolith on its sledge at least a mile a day.
Archaeologists used to think that the bluestones were taken to the coast at Milford Haven and floated on rafts or boats and along the Severn Estuary and Bristol Avon. Now that the rhyolite and spotted dolerite quarries, as well as Waun Mawn circle, have been found on the north side of the Preseli hills, this seems unlikely since they would have to have been taken over the top of the Preseli ridge. An easier route would have been by land, eastwards along what is now the A40, passing Crickhowell and Abergavenny, the area where the Altar Stone is thought to have come from. Perhaps this monolith was picked up along the way!
Why did they do it?
We don’t really know why, but since the bluestones appear to have formed the first stone circle at Stonehenge, the reason for moving them was integral to the very purpose of Stonehenge itself. One possibility is that this was an act of union, bringing together two powerful Neolithic tribes. Another theory is that the Neolithic people of Preseli left their homeland to re-establish themselves with their ancestral stones at one of the great centres of their Neolithic world. Whatever the reason, it is exciting that Brynberian may hold more secrets of Stonehenge!
Ixer, R.A., Bevins, R.E. and Pirrie, D. 2020. Provenancing the stones: mapping the Stonehenge bluestones with mineralogy. Current Archaeology 366: 34–41.
Parker Pearson, M. 2012. Stonehenge: exploring the greatest Stone Age mystery. London: Simon & Schuster.
Parker Pearson, M. 2016. Secondhand Stonehenge? Welsh origins of a Wiltshire monument. Current Archaeology 311: 18–22.
Parker Pearson, M., Pollard, J., Richards, C., Schlee, D. and Welham, K. 2016. In search of the Stonehenge quarries. British Archaeology 146: 16–23.
Parker Pearson, M. with Pollard, J., Richards, C., Thomas, J. and Welham, K. 2015. Stonehenge: making sense of a prehistoric mystery. York: CBA.
Parker Pearson, M., Pollard, J., Richards, C. and Welham, K. 2017. The origins of Stonehenge: on the track of the bluestones. Archaeology International 20: 54–9. doi: http://doi.org/10.5334/ai.353
Pryor, F. 2018. Stonehenge: the story of a sacred landscape. London: Head of Zeus.
More specialised reading
Bevins, R.E., Ixer, R.A. and Pearce, N.G. 2013. Carn Goedog is the likely major source of Stonehenge doleritic bluestones: evidence based on compatible element geochemistry and principal components analysis. Journal of Archaeological Science 42: 179–93.
Bevins, R.E., Ixer, R.A., Webb, P.C. and Watson, J.S. 2012. Provenancing the rhyolitic and dacitic components of the Stonehenge landscape bluestone lithology: new petrographical and geochemical evidence. Journal of Archaeological Science 39: 1005–19.
Bevins, R.E., Pirrie, D., Ixer, R.A., O’Brien, H., Power, M.R., Shail, R.K. and Parker Pearson, M. 2020. Constraining the provenance of the Stonehenge ‘Altar Stone’: evidence from automated mineralogy and U-Pb zircon age dating. Journal of Archaeological Science. 120: 105188.
Nash, D., Ciborowski, T.J.R., Ullyot, J.S., Parker Pearson, M., Darvill, T., Greaney, S., Maniatis, G. and Whitaker, K.A. 2020. Origins of the sarsen megaliths at Stonehenge. Science Advances.
Parker Pearson, M., Bevins, R., Ixer, R., Pollard, J., Richards, C. and Welham, K. 2020. Long-distance landscapes: from quarries to monument at Stonehenge. In R. Boaventura, R.. Mataloto and A . Pereira (eds) Megaliths and Geology: proceedings of a conference in memory of Rui Boaventura. Redondo: Centro Cultural do Redondo. 183–200.
Parker Pearson, M. 2019. Stonehenge’s bluestones. In A. Teather, P. Topping and J. Baczkowski (eds) Mining and Quarrying in Neolithic Europe: a social perspective. Oxford: Oxbow. 83–100.
Parker Pearson, M., Bevins, R., Ixer, R., Pollard, J., Richards, C., Welham, K., Chan, B., Edinborough, K., Hamilton, D., Macphail, R., Schlee, D., Simmons, E. and Smith, M. 2015. Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge. Antiquity 89: 1331–52.
Parker Pearson, M., Pollard J., Richards, C., Welham, K., Kinnaird, T., Shaw, D., Simmons, E., Stanford, A., Bevins, R., Ixer, R., Ruggles, C., Rylatt, J. and Edinborough, K. 2021. The original Stonehenge? A dismantled stone circle in the Preseli hills of west Wales. Antiquity 95.
Parker Pearson, M., Pollard, J., Richards, C.,Welham, K. Casswell, C., French, C., Shaw, D., Simmons, E., Stanford, A., Bevins, R.E. and Ixer, R.A. 2019. Megalithic quarries for Stonehenge’s bluestones. Antiquity 93: 45–62.
About the author
Mike Parker Pearson is Professor of British Later Prehistory at University College London and a Fellow of the British Academy. He has been researching Stonehenge since 2003 and has been investigating the sources of its bluestones since 2011. His archaeological career has taken him to many parts of the world including Madagascar, Syria, Greece, the Outer Hebrides and Easter Island.