The quiet abandonment of the great Neolithic exodus

Daisy Eleanor Spencer, Karen Molloy, Mike Parker Pearson, Ralph Fyfe & Aaron Potito (19 Oct 2025): Prehistoric Landscape Change Around the Sources of Stonehenge’s Bluestones in Preseli, Wales, Environmental Archaeology, DOI:10.1080/14614103.2025.2574741
https://doi.org/10.1080/14614103.2025.2574741

Since our old friend MPP scatters hypotheses just as others might scatter confetti, it's difficult to know what he actually thinks about anything. But I have been reflecting on the fact that the paper by Daisy Spencer et al (including MPP) has received no media attention whatsoever -- so we can assume that there was not even a press release from UCL........ I wonder why?

I wrote to Daisy Spencer about the article and its weird obsession with Stonehenge, but have received no reply. I wonder why?

In the present circumstances it's difficult to know whether we are supposed to accept that there was a mass stone-carrying exodus from Pembrokeshire around 5,000 years ago. Maybe yes, maybe no. Maybe we are supposed to think there was a mass exodus, which does not show up in the environmental change records because a few human beings were left behind, tasked with obliterating all traces of quarrying and stone transport, and carrying on as before? Or maybe the stone-carrying expeditions were conducted by an elite and mysterious group that was in possession of secret knowledge of igneous petrology and stratigraphy?

I haven't given much coverage to this idea, mainly because it is so proposterous. But we can see some of MPP's thinking on a corporate, elite management or specialized lineage-driven transport model in his chapter in the edited volume "Trade Before Civilization: New Perspectives on Long-Distance Trade and Social Complexity" (Cambridge University Press, 2022), and in his highly selective arguments in "The Power of Ritual in Prehistory: Secret Societies and Origins of Social Complexity."

With nowhere else to go, MPP is now forced to drift back toward a variation of the old "elite coercion" or "religious pilgrimage" theories, where a specialized group of elite prehistoric managers (who were of course in possession of esoteric or secret knowledge) somehow convinced a simple and settled West Wales population to let them strip their landscape of their sacred monuments and drag them 140 miles away over land, leaving the local farmers behind to tend the fields.

We will hear more about this as more and more pieces of the edifice collapse. But isn't it rather entertaining that MPP is now homing in on druids and Neolithic bards, having spent much of his academic life assuring us all that Stonehenge has nothing whatsoever to do with the druids? All this just at a time when we are having fun with the Welsh National Eisteddfod, the Gorsedd of Bards, and a Gorsedd Circle made of glass fibre imitation stones? And not so long ago, at the time of the summer solstice, the druids all had a whale of a time prancing around at the old stone ruin on Salisbuiry Plain. Iolo Morgannwg must be chortling away as he looks down from his place in heaven.

More on this shortly..........

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My recent post on the paper by Spencer et al:

https://brian-mountainman.blogspot.com/2026/07/the-preseli-landscape-change-paper.html

A reminder of what I said in 2019:

https://brian-mountainman.blogspot.com/2019/04/was-there-neolithic-mass-exodus-from.html

So what evidence might there be for a large-scale cultural upheaval in West Wales roughly in the period 5,500- 4,500 BP -- the crucial thousand years in the Stonehenge story? So far as I can see, none at all. True, there are signs of a decline in the construction and use of megalithic tombs (cromlechs or dolmens) for collective burials, and signs of an increase in the setting up of standing stones, either singly or in "settings". And Pembrokeshire does not seem to have been affected by the trend of building large and impressive passage graves like Bryn Celli Ddu on Anglesey and Newgrange in Ireland; but in considering this difference Darvill and Wainwright, in their big 2016 chapter in "Pembrokeshire County History", say that Pembrokeshire was by no means isolated, but simply part of a quite different network of connected politics in which an emphasis as placed on individual graves sometimes covered with round cairns of stone. In their chapter it is difficult to extract hard facts from a context in which Stonehenge always lurks in the background, with circular reasoning much in evidence -- but suffice to say that there is no suggestion, anywhere, of a major hiatus that must have accompanied a "folk exodus" of people carrying stones or petrified ancestors to Stonehenge.

In contrast, there are many signs of continuity, with the adoption and abandonment of different traditions of building things and burying the dead. One tradition that appears to have been neither adopted, used or abandoned is the tradition of erecting large standing stone circles -- which maybe explains why MPP and his merry band have been hunting fruitlessly for "Proto-Stonehenge" for the last eight or nine years. Another tradition that never was developed, used, or abandoned, was the tradition of quarrying large monoliths from the living rock in designated quarries. And yet another assumed tradition for which we have no evidence at all was the tradition of transporting large monoliths across country for great distances.

So, as far as I can see, there is no evidence to support the hypothesis of a major exodus or series of expeditions eastwards from Pembrokeshire towards Stonehenge for the purpose of political unification or for any other reason. On the contrary, the evidence suggests a fairly small and relatively isolated community developing some local trends, copying or adapting others, and maintaining trading links with other communities in all compass directions. The idea that there was a sort of Neolithic "El Dorado" or Holy Land in West Wales is entirely fanciful; megalithic remains are no more spectacular or abundant here than they are everywhere else. If there was a threat from the east at any stage, involving immigrants from the near continent, it would have been strange indeed for local people to have moved TOWARDS the source of the threat, carrying with them assorted symbols of their cultural identity in the form of more than 80 very large stones.

A famous quotation.....

 

Came across this on Hugh's Facebook page. For which many thanks.  Couldn't resist using it.  Quote from a famous archaeologist who shall be nameless....... 

Julian Richards on the Bluestones

 

Julian Richards's hilarious stunt in one of his latest videos on Stonehenge.  This, I fear, is the sort of Stonehenge pseudo-science that we have to deal with nowadays. Should we laugh or should we cry?

In his commentary, Richards says:  "Did the glacier just conveniently deposit about 80 stones of just the right size here on Salisbury Plain, and nothing else?  Where are all the other stones?  Where's the evidence?"

That's the classic straw man tactic.  Invent an assumption that you would like other people to have held, and then rubbish it.  As far as I know, nobody has ever claimed that "80 stones of just the right size" were dumped on Salisbury Plain.  And where does the figure of 80 come from?  Answer -- inside Richards's head. He does not know that the Stonehenge bluestone or sarsen stone settings were ever completed.  We know about 43 bluestones, and maybe that's all there ever were.  And the most parsimonious explanation for the apparent abundance of stone sockets is to say that there never were enough stones, and that the builders used them in one experimental setting after another before finally giving up on the project. 

As for the silly blank pages stunt, he jokingly refers to "a complete guide to all the glacial erratic stones such as Welsh bluestones known on Salisbury Plain to have been naturally deposited."  So who decides what is naturally deposited, and what is not?  If I tell him that bluestone 32 was naturally deposited before being used in a stone setting, how is he planning to prove me wrong?

This is not good science.  But are we surprised?

Landscape and sediment modification on Salisbury Plain

Sarsen litter on Fyfield Down. Here today, but yesterday somewhere else......

Some of the Stonehenge bluestone erratic boulders.  Here today, yesterday somewhere else, higher up.   Courtesy Simon Banton.

I have visited this topic on many previous occasions in this blog,  for example here: 

https://brian-mountainman.blogspot.com/2022/02/southern-england-where-is-glacial-limit.html

https://brian-mountainman.blogspot.com/2016/12/sarsens-and-solution-hollow-dilemma.html

https://brian-mountainman.blogspot.com/2016/08/extraction-pits-solution-hollows-post.html

https://brian-mountainman.blogspot.com/2022/02/salisbury-plain-no-traces-of-ice-action.html

My conviction that Salisbury Plain was glaciated a very long time ago is stronger than ever, and I have argued consistently that there may well have been a patchy cover of till (derived from the west) which has been destroyed and redistributed over the course of 45,000 years or more of continuous denudation.  Oh no, say the usual suspects, if there had been a glaciation you would expect to find a scatter or a trail of erratics across the chalk downland, patches of till and fluvioglacial deposits, and maybe even a terminal moraine or two..........  These people are slow on the uptake, and refuse to accept that there are indeed abundant erratics scattered across Salisbury Plain on the surface and in assorted sediiments, and that the bluestone monolith assemblage (including the Boles Barrow bluestone) is as fine a collection of glacial erratics as you are ever likely to see.

I have also explained in a recent post that the chalklands of Salisbury Plain provide an extremely aggressive geochemical environment in which glacial and other deposits are very readily destroyed:

https://brian-mountainman.blogspot.com/2026/08/salisbury-plain-serene-landscape-but.html

Murton and his colleagues have also made a persuasive case for the destructive operation of periglacial processes, especially when the chalk lands have been "solidified" by the presence of permafrost:

https://brian-mountainman.blogspot.com/2023/01/periglacial-britain.html

https://www.lyellcollection.org/doi/10.1144/EGSP28.5

During the Quaternary, these periglacial processes have perhaps been in operation for 25% of the time, with each glacial episode ushered in by a prolonged periglacial phase and each interglacial ushered in by a phase of rapid ice wastage and rapid warming.   The temperature graph shows a sort of "saw tooth" pattern.  

However, these geomorphological considerations are brought into even sharper focus when we consider the landscape history of Salisbury Plain. In brief, the Plain is not where it used to be (on the altitude chart) when it was last affected by glacier ice, so all of the deposits that were on the chalk surface must long since have disappeared.  Their calcareous components will have been dissolved away, and their quartz-rich components will have been disaggregated and redistributed.  Only in the most freakish or  favourable of circumstances can small fragments of these original sediments have survived in situ. (I use that phraseology because I don't like the word "impossible"..........)

So to what extent has the land surface been lowered during the last 450,000 years or so?  There are several basic calculations in the literature.  These can be tested one against another.

1.  In the assessments of chalk dissolution and land surface altitude reduction since the formation of the Paleogene silcrete duricrust that gave rise to the sarsen stone scatter, the figure of 30 - 100 m appears in the literature, dending on local circumstances.  Tectonic and regional climate changes have varied from place to place, but let's take a conservative figure to 50m of land surface lowering.  Initially the rate of surface lowering was around 2.5 mm per millennium.  Because of regional uplift and climate changes, the rate of lowering increased tom around 10mm per millennium from the beginning of the pliocene, accelerating again to 19.2mm per millennium during the Quaternary -- associated with violent swings in climate and  glacial / interglacial oscillations.  Since the onset of the Anglian glaciatiuon, surface lowering of between 7 and 14m has been suggested, with a widely accepted average calculation of 8.6m.

2.  Modern geomorphological studies suggest that in the UK, under current temperature and rainfall conditions, surface lowering on the chalk is around 15-30 mm per millennium.

3.  The Norber Erratics in northern England, left stranded on a limestone pavement at the end of the LGM, now stand on pedestals c 30 cm high.  That indicates baseline surface lowering at 20 - 25 mm per millennium. 

4.  Surface lowering in the Driftless Area (USA) has been measured at 10-15 mm per millennium, on much more resistant bedrock of Palaeozoic sandstones and dolomite.  The Quaternary rate of surface lowering on the chalk plateau of Normandy is estimated at around 20mm per millennium.

There is a very satisfying equivalence in all these figures.  The land surface of Salisbury Plain has been lowered by 8-10m over the last half million years.  The landscape as it was at the time of the Anglian Glaciation (or the Wolstonian, for that matter) is simply not there any more.  End of story.

Revisiting Newall's Mound

Newall's Mound is on the tight bend, just under the words "The Avenue"

Newall’s Mound is a distinctive, low raised hummock located near the "elbow" bend of the Stonehenge Avenue. Named after the pioneering archaeologist Robert Newall, who mapped much of the prehistoric landscape, the mound has been the subject of several archaeological investigations to determine its origin. 

Way back in 2012, I spent some time pondering on txhe origin of Newall's Mound.  Much flood water has gone under the bridge since then,  and on looking at my old post I saw that there is a solution hollow under Newall's Mound.  I was a bit puzzled by that.

https://brian-mountainman.blogspot.com/2012/11/newalls-mound.html

In my post I suggested that on the chalk downlands the solution hollows are the places where the solution of the chalk is most concentrated.  I think my assumption might have been quite wrong.  Having done a lot more reading,  it now seems to me to be much more likely that the solution hollows all over Salisbury Plain are very old indeed, and that they contain residues of ancient deposits that have been broken down and redistributed over hundreds of thousands of years while the "clean chalk" surface on the flanks of the hollows has been systematically lowered by solution.  In other words, there has been in inversion of the topography.  The hollows which were long since the sinks for surface detritus have actually seen a slowing down of the rate of surface solution, which has gone on unchecked elsewhere across the landscape.  

So the hollow becomes a mound, capped by 1.5m of "clay with flints" as we see here in this little feature at Stonehenge.  Sounds absurd?  Not really.  Just think of how kames are formed in glacierized landscapes.  In an ice wastage environment, glaciofluvial materials and associated debris accumulate in hollows in the ice surface.  Glacier ice eventually wastes away completely, and as it does so the old hollows are transformed into hillocks.  The high points in the landscape disappear, leaving befind a veneer of any englacial or supraglaciat deposits that might have been present.  Now substitute chalk for ice, and all is explained.

Topographic inversion and the formation of eskers and kames -- associated with ice wastage

I need to give this more thought........

Interestingly, the mound near the Avenue bend was investigated by Dr John Evans in 1984.  I met John a few times, at a delightful coastal cottage not far from Abermawr in Pembrokeshire.  John was married to Nora Figgis, whom I mentioned on this blog a few days ago.........

Evans, J G. (1984). Stonehenge – the environment in the Late Neolithic and Early Bronze Age and a Beaker-Age burial. Wiltshire Archaeological and Natural History Magazine 78 :7–30.

Salisbury Plain: serene landscape but lethal geochemistry

 

Almost all of the textbooks and archaeological papers that devote space to the Stonehenge bluestones make three claims:  (1) that there is no till or any other glacial deposit on Salisbury Plain; (2) that glacial erratics are entirely absent; and (3) that Salisbury Plain was beyond the reach of any known British glacier or ice stream.  

The latter claim was of course made by HH Thomas back in 1923, and has been taken as an article of faith ever since then, even by certain geomorphologists who should know better.  We now know that Thomas misrepresented the evidence by falsely claiming that the outermost ice edge in the Celtic Sea / Bristol Channel arena lay just to the south of the south Pembrokeshire coast, flying in the face of evidence from many of his peers that the ice had on occasions extended much further southwards and eastwards.  We now know that there are abundant traces of glaciation on the coasts of Somerset, Devon and Cornwall -- although evidence of the inland incursion of glacier ice is still hotly debated.  Nonetheless, we know from field research and from modelling studies that it was perfectly possible for glacier ice to have extended well to the east of the chalk escarpment.  Many of these studies have been cited on this blog.

An attempt to portray the extent of the "Greatet British Glaciation", based on computer modelling by various authors and on field evidence.  This is a cautious reconstruction in that the ice margin is shown at the western edge of Salisbury Plain.  Some models show the chalk downs and Salisbury Plain WITHIN the glaciated area.

One of a multitude of computer models showing a somewhat greater ice extent.  This is from Edwards et al, 2017.  Models like this are not "evidence" of past glaciations -- they are mathematical models based on an author's understanding of glaciological theory and an interpretation of field evidence.  As with all modelss of this type, rubbish in, rubbish out.......

As far as erratics are concerned, it is disingenuous to pretend that they do not exist on Salisbury Plain.  As pointed out by Kellaway, Olwen Williams-Thorpe and many others, they are abundant -- with at least 40 different rock types represented in the bluestone monolith / cobble / packing stone assemblage and in the debitage at Stonehenge and further afield.  Whether these erratic materials can be labelled as "glacial erratics" is another question entirely.  But as I have repeated many times, bluestone shapes and surface characteristics point unequivocally towards glacial entrainment and transport -- and if things look like glacial erratics, that is probably what they are. Why is that such a big deal?

Then we come to the claimed absence of glacial deposits on Salisbury Plain. Well, absence of evidence is not evidence of absence -- and the great majority of the sediments on Salisbury Plain are of course unexplored and unknown.  Even within the Stonenge stone setting, 50% of the surface sediments have never been investigated.  With the "impossibility of glaciation" accepted as an article of faith, we see confirmation bias in almost every study in the literature.  Over and again we see that sediments containing foreign erratic material are immediately dated as younger than the supposed known date of bluestone arrival; it does not seem to have occurred to the establishment faithful that "date of first use" is not at all the same as "date of arrival", and that erratics might well have been lying around in the Stonehenge area for hundreds of thousands of years before people arrived and started messing about with monumental ambitions.

So could there be glacial deposits lying around on Salisbury Plain, undiscovered?  Of course that is a possibility.  We see various clues in the strange and intriguing deposits lumped together under the "clay-with-flints" label.  But then we come to a point that is hardly ever made by archaeologists, geologists or anybody else: namely that the chalk downs of Salisbury Plain and adjacent areas are geochemically lethal, and are perfect places for the efficient degradation and destruction of any scattered patches of till and glaciofluvial deposits that might once have existed. 

If glacial ice did once extend across the chalk downs, what might the  traces of this glaciation have looked like?  Well, there will probably not have been any massive terminal moraines located at ice edges.  Prior to ice arrival near the peak of a glacial episode, we can assume that the ground surface would have been deeply frozen or locked in permafrost.  That points in turn towards cold-based ice, moving slowly and not affecting much basal erosion -- and in turn not depositing vast thicknesses of till and other materials such as we see in parts of Eastern England where chalk bedrock underlies Late Devensian and other till sheets.

Lee and Roberson (2025) contains an interesting discussion on the types of glacial features that occur in the ice marginal zone, dependent upon thermal regime, bedrock characteristics etc.  They make the point that the edge of a till sheet rarely marks the maximum extent of ice in a landscape.

https://www.sciencedirect.com/science/article/pii/S0016787824000683

So, around 450,000 years ago, if the chronology of ancient glaciations is correct, there may well have been a patchy spread of glacial and glacio-fluvial deposits on the chalklands of Salisbury Plain.  So should they not still be there, available to be mapped and examined?  The short answer to that is "No".  The long answer is that the geochemical environment on Salisbury Plain is far too aggressive -- and even lethal -- for ancient glacial deposits to have survived.  The deposits -- however extensive they might have been -- would have been quite calcareous, as demonstrated by the Devensian Irish Sea till of the west Wales coasts and by the Fremington Till on the coast of Devon.  It must have been composed for the most part of clay and silt deposits dredged from the floor of the Bristol Channel, with other calcareous additions coming (for example)  from the Mendips and from the Black Rock limestone beds around Frome.  Gilbertson and Hawkins, and other workers, have described the till deposits of Somerset and their associations with marine shell fragments, suggesting a shared chemistry.  

So the Salisbury Plain till was probably calcareous -- meaning that its chances of long-term survival were virtually zero.  Because the chalk is highly porous and lacks cementing minerals, rainwater mixed with soil acids percolates straight down, soaking the landscape. Any loose calcareous sediments dropped onto the plain (such as limestone erratics or older shelly sands) are subjected to continuous, downward leaching by acidic water. Without the specific point-source degassing or coastal evaporation seen in Wales to precipitate cements, the carbonate is entirely dissolved and flushed deep into the aquifer, leaving no physical trace.  This aggressive leaching is so intense that even relatively resilient detrital minerals (like apatite) are chemically dissolved and structurally stripped from Salisbury Plain's surficial layers over hundreds of thousands of years.

However, in this broadly very destructive scenario, the chemistry also shows that erratic boulder survivals are not just possible but probable.  Sarsen stones derived from an ancient duricrust layer were eminently survivable, being composed of almost 100% silica.  The "bluestone" lithologies from Pembrokeshire—primarily spotted dolerite (diabase) and various rhyolites/tuffs—are composed of highly resilient silicate minerals like quartz, plagioclase feldspar, and pyroxene. Unlike calcium carbonate, these minerals are resistant to weak carbonic acid.  Even if small carbonate grains dissolve, un-weatherable microscopic minerals do not disappear.  Igneous rocks like the Pembrokeshire igneous bluestones are packed with ultra-durable heavy trace minerals, such as zircon, rutile, tourmaline, and apatite.  Placed on Salisbury Plain, a large dolerite block would be expected to survive hundreds of thousands of years of chemical weathering, whereas a limestone or chalk pebble in a surrounding till matrix would dissolve completely.

In addition to the "chemical hostility" of the Salisbury Plain environment, we have to consider the physical weathering effects of climate change over almost half a million years -- with  multiple oscillations in wetting and drying, heating and cooling.  Chalk absorbs a lot of water.  During past permafrost freeze-thaw cycles, the surface layer of chalk must have shattered into a fine, paste-like slurry.  Any glacial till, erratic boulders, or paleosols caught in this zone would also have been violently churned up by cryoturbation and washed down valleys as mobile gravelly solifluction deposits (historically termed "coombe rock" or "head"). Because these redeposited sediments could not cement together, they remained loose, soft, and completely vulnerable to being wiped away by subsequent fluvial and colluvial processes during warmer episodes.

So the scenario is one of widespread sediment destruction with some survivals.  What of the residues and lag deposits that must remain when calcium carbonate rich rocks are dissolved away?  This is where we return to some of the enigmatic sediments on Salisbury Plain -- and in particular the "clay with flints" that we have discussed on many occasions.  The physical and mineralogical composition of this material strongly proves that it contains a large amount of detritus that did not come from the underlying chalk.  Pure chalk contains very little clay and sand. To produce a one-metre-thick layer of clay-with-flints purely from chalk dissolution, you would have to dissolve hundreds of metres of bedrock. Mineralogical analyses show that much of the matrix clay (like illite and kaolinite) and quartz sand actually comes from reworked, younger overlying formations (like the Paleogene Reading and Thanet Formations) and unknown exotic surficial inputs.  In many areas of the downlands, the clay-with-flints loses its classic red-clay appearance and grades into poorly sorted, unstratified, gravelly deposits packed with sub-angular flints and erratic quartzites. This structural signature is virtually indistinguishable from a highly weathered, decalcified, cryoturbed periglacial "head" or an ancient, deeply rotted till or fluvioglacial accumulation.

Despite the heavy dilution, geologists have occasionally confirmed a persistent presence of exotic "foreign" stones. Round, exotic quartzite pebbles (often historically lumped together as part of the "Northern Drift" or derived from old Triassic Pebble Beds) are well-documented across the downlands. These are classic indicators of far-travelled, non-local glacial, fluvioglacial or fluvial transport.  Over the decades, independent Quaternary geologists (most notably our old friend Geoffrey Kellaway) reported finding small, erratic pebbles of igneous and metamorphic material—including fragments resembling southwestern and Welsh lithologies—in deep solution features and surficial deposits across the wider Wessex region.

Ah -- solution features.  Now we are getting serious, and feel another comment about Parker Pearson's "periglacial stripes" coming on.  Watch this space.........

The Croft Gorsedd Circle

 

On doing some more digging in a minefield of Facebook groups and pages on matters relating to the Bluestone Eisteddfod, and from talking to certain people who are well informed, I have small matters to report.  The stone circle at Croft is on land belonging to Croft Farm, and it was put up by the local Eisteddfod Committe with the help of assorted other organizations and lots of volunteers.  It was "unofficial" in that it was not put up by the main National Eisteddfod Committee, whose work was restricted to the designated eisteddfod site.  But one of the beauties of the eisteddfod is that it attracts hundreds of voluntary events and gestures around the edges, before and during the eisteddfod itself, stimulating a vast amount of creative activity and involving an army of volunteers.  So the building of the Croft "Gorsedd Circle" was one of these good-natured and slightly tongue-in-cheek events, planned and executed with precision in late June and early July.  

First, the site was chosen, and then a hedge alongside the road was removed in 2025.  As far as I can gather, the stones were donated by a farmer from the Mynachlogddu area (from private farmland).  They were transported to the site in late June, laid out and put into the ground in early July.  Later, the electric floodlighting system was installed by a local electrical contractor, and the flower boxes at the roadside were put in by Menter Iaith Sir Benfro.  This was all done slightly under the radar, but there was some coverage on the S4C TV channel, and in local Welsh language news media.  I picked up some photos from assorted Facebook pages........

The installation is meant to be a permanent reminder of the eisteddfod, which is fair enough, since the official Gorsedd Circle on the Maes was made of the glass fibre imitation stones that are installed and used and taken away again each year.   I doubt that any planning permission was required, since there is no change of use on the land, and the 11 stones were probably put up as scratching stones for the convenience of the farmer's cattle and sheep.......

 All we need now, to complete the story, is for a worthy  Cadw inspector to come along and to designate the stone circle as a Scheduled Ancient Monument, on the basis that it has great historical and cultural significance.......