More fantasising on the Altar Stone

Suggested area (pink) across which Late Devensian erratics from northern Scotland might have been distributed. The map also shows the "footprint" of the Anglian glaciation, during which ORS erratics might have been carried even further southwards.

A very strange article has just been published, in the very respectable JQS journal which normally steers well clear of fantasies and speculations.  I'm rather surprised that it was accepted for publication, since it contains virtually no new data and builds yet more speculation onto an already very speculative narrative. In short, the article is filled with assumptions built on uncertainties, and the media coverage of it is completely bonkers.  Not surprisingly, some journalists flag up the "glacial transport" side of the story as an exciting discovery, while others claim that the human transport hypothesis is now proved.  Like the JQS article, it's all a bit of a mess.........

Here is the press release from Curtin University in Australia:

https://www.curtin.edu.au/news/media-release/study-details-epic-transportation-of-stonehenge-stone-across-ancient-britain/

The article:

Clarke, A. J. I., Veness, R. L. J., Kirkland, C. L., Clark, C. D., Gandy, N., Emery, A. et al. (2026) From Highlands to Henge: Refining the Provenance and Transport Pathways of Stonehenge's Altar Stone. Journal of Quaternary Science, 1–8. https://doi.org/10.1002/jqs.70080

 https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.70080

ABSTRACT:

The Altar Stone, the 6000 kg central sandstone megalith at Stonehenge in southern England, is suggested to have originated from the Orcadian Basin in northeast Scotland, some 700 km away. However, its source location within this large basin remains unresolved and its mode of transport uncertain. Proposed mechanisms include Neolithic human transport via marine or overland routes or southward movement as a glacial erratic. Here, we combine sandstone provenance analysis with ice flow modelling to constrain potential sources and transport pathways. Ice sheet reconstructions show that southward transport vectors from northeast Scotland were highly localised, making precise source determination critical to evaluating glacial erratic transport plausibility. Candidate source areas farther south within the Orcadian Basin are more compatible with southward glacial dispersal, but show weaker correspondence with the detrital zircon age spectra that characterise the Altar Stone. By contrast, sandstones from Caithness on the mainland of northeast Scotland provide the closest match in zircon age structure; yet, modelled glacial transport from this region is predominantly towards the north‐east, with a localised south‐eastward pathway directed towards Dogger Bank. Glacial dispersal to Dogger Bank would reduce the anthropogenic transport distance required to Stonehenge from 700 km to 400 km. However, such a model raises an additional temporal problem, as Dogger Bank was inundated by post‐glacial sea‐level rise before the Altar Stone likely arrived at Stonehenge. Glacial transport may have provided an intermediate stage in the stone's journey, but alone cannot account for the final emplacement on Salisbury Plain. Even under a glacially assisted scenario, substantial anthropogenic transport would have remained necessary.

============

Right from the outset there is bias that should have been picked up by the referees. In their introductory paragraph the authors refer to "three lithologies" in the "building block" collection at Stonehenge, specifically creating a seperate category for the Altar Stone.  Ixer and Bevins, for reasons that are not difficult to discern, decided not so long ago that the Altar Stone should no longer be referred to as a "bluestone" but should be dignified by the creation of a new rock category.  There is no earth science logic to that, since the bluestones (of all shapes and sizes) found in the Stonehenge landscape do not all come from Mynydd Preseli, and the Altar Stone is not the only sandstone.  If we look at the sarsens and the erratic bluestones around Stonehenge, there are scores of lithologies represented, and ORS sandstone is just one of them.

This labelling device, right at the beginning of the article simply flags up the authors' specific intention to demonstrate that the Altar Stone was not just special or sacred, but that it was even more sacred than the bluestones.

In mentioning that Parker Pearson's Waun Mawn "lost bluestone circle" has been criticised, they cite Darvill (2022) who refuted the hypothesis on archaeological grounds, but they fail to cite my much more comprehensive 2024 criticism and dismissal (in the "Holocene" journal) of the MPP narrative on earth science grounds.  One might have expected an acknowledgement of this in an article published in JQS..............

In referring to monolith transport, the authors refer to the glacial theory, but say "recent detrital zircon–apatite fingerprinting of Salisbury Plain river sediment found no evidence that glacial processes delivered the bluestones to southern England (Clarke and Kirkland, 2026)".  It would have been more honest for the lead authors to state that their own zircon study is deeply defective, since the findings are based on just four river sand samples (accepted as valid without any refence to sampling procedures) and a lack of any control studies.  This and other defects were discussed in another post on this blog:

https://brian-mountainman.blogspot.com/2026/03/probable-bias-in-zircon-apatite.html

We have similar problems with the other key samples used by Clarke and others in their studies of the Altar Stone.  All 4 of them -- from Stonehenge, Orkney and Caithness -- are surrogate samples, not collected by the authors during fieldwork but taken from second hand sources:

ALTAR STONE
1 National Museum of Wales ( assumed to have been excavated Hawley in the 1920s)
2 Salisbury Museum (assumed to have been collected from the underside of the Altar Stone in 1844)

ORCADIAN BASIN SAMPLES
Two Old Red Sandstone rock samples from the Orcadian Basin, bought from Natural Wonders Ltd, Whitby:
1 Cruaday, Orkney
2 near Spittal, Caithness

The Altar Stone samples are simply assumed to be truly representative of the Altar Stone itself -- but if that attribution is faulty, then this article, like several others, becomes nonsensical.  Given this fundamental research defect, why on earth did not one or another of the authors actually pop up north for a few days with a geological hammer and collect some proper, fully authenticated, rock samples?

Anyway, on a more positive note I welcome and agree with the paragraph on erratic transport routes and with the point that glacial erratics take thousands of years to be transported within the ice, during which ice flow vectors can shift in direction.

Quote:

This motivated us to model trajectories of glacial erratics, accounting for such shifting flow vectors over time to yield predictions of transport routes and distance. A complicating factor is that the Orcadian Basin sat near the ice sheet's north–south ice drainage divide (>1 km thick at times). Small movements (tens of kilometres) of this ice divide, as the ice sheet fluctuated, could have transported boulders in a multitude of directions. An investigation of the possible time-integrated flow routes is thus warranted to explore the plausibility of southward transport as an erratic. The key here is that rather than considering a single ice transport vector, we now examine if the Altar Stone could have first been transported in one direction and later in another as ice flow directions shifted. Could such multistage ice transport have carried the Altar Stone closer to Salisbury Plain? Given the complexity of ice flow directions in the region, refining likely locations of the source area is crucial to exploring this time-integrated ice flow analysis of possible erratic pathways.

This is fine, and could also, of course,  be applied to the west coast of Scotland in our attempts to discover how erratics apparently from the Western Isles might have been transported to the coasts of the Bristol Channel.  Indeed, I have already cited another article by Veness and others in a recent post about Scottish erratic trails.

https://brian-mountainman.blogspot.com/2026/05/scottish-erratics-and-irish-sea-ice.html

In the discussion of "detrital zircon data sets" from the Orcadian basin and elsewhere, the authors present no new fieldwork and no new samples.  They depend entirely on the published work of other authors, and their conclusions are therefore based on pre-selected data sets, with a vast expanse of ORS sandstone territory unsampled and effectively ignored.  This represents yet another powerful bias in the work.

On the matter or erratic trains, the authors suggest -- in line with BRITICE and other modelling work -- that erratics derived from Caithness and Orkney are unlikely to have found their way to the Dogger Bank during the Late Devensian Glaciation (LGM), but that they might have travelled south if they had previously been emplaced by eastward-flowing ice in (for example) the Wolstonian or Anglian Glaciation and then later entrained by a southward flowing ice stream.  On the other hand ORS erratics from New Aberdour or the Inverness area could well have been entrained on the south side of an ice shed and transported southwards to the Dogger Bank.    In other words, the modelling work suggests that the Inverness and New Aberdour areas are more likely to have provided Dogger bank erratics than outcrops in Caithness or Orkney.  I have no problem with any of that, except to say that other outcrops of ORS around the Midland Valley Basin were even more likely to have provided erratics for the southward-flowing ice stream in the North Sea. 

In the section of the article entitled "Human and ice transport?" the authors seem to lose touch with reality.  First, they accept that the Stonehenge landscape "lacks the detrital signature expected from direct glacial delivery of megalith-derived material from northeast Scotland".  They cite Clarke and Kirkland 2026, but (as mentioned above) they fail to appreciate that their conclusion is highly contentious, having been based on just four sand samples about which we know virtually nothing.  Clarke and Kirkland are joint authors of the article which we are scrutinizing.......... enough said.

 Then the authors embark on a series of speculations on "human agency" in the movement of the Altar Stone from Dogger Bank to Stonehenge which are so bizarre as to be embarrassing.  How this section got through the refereeing process, maybe we will never know........

They suggest that Dogger Bank might have been a "topographic high point in the landscape" which might have held some cultural significance for Palaeolithic or Mesolithic inhabitants. They then suggest that the Altar Stone, found as an erratic, must have been special or sacred enough to justify collection and transport towards Stonehenge via maritime and land-based pathways three thousand years before it was incorporated into the Stonehenge monument.  Talk about forward planning.........!!!

The idea of Dogger Island and its sacred stone -- seized upon, of course, by the media -- is so absurd that even our old friend MPP might be worried about it!  There is no evidence at all that Palaeolithic or Mesolithic tribesmen in the period 9,000 - 7,000 BP had either the desire or the capability to move a six-tonne slab of rock from one place to another in Doggerland or anywhere else.  As far as I am aware, there are no Palaeolithic of Mesolithic standing stones anywhere in Europe.  At the time of Dogger Island's final inundation, and indeed for millenia before that, this was a densely wooded landscape of rivers, lagoons, bogs, fens and marshes -- good hunting, fishing and gathering territory.  But I think we can safely dismiss the idea that the inhabitants knew that their island world was going to disappear, and that they planned and executed a move westwards for a large sacred stone while the going was good.  Of course the media love this sort of narrative, but it's completely bonkers.  

The "Dogger Bank scenario" involves "prolonged cultural significance or multiple-phase activity, across an exceptionally large temporal gap" -- but the authors also suggest that the boulder might have been moved south-westwards from the North Sea coast during the Anglian Glaciation and then dumped somewhere near the Chilterns ice edge.  This would have involved a relatively short "anthropogenic transport route" along the Berkshire Ridgeway towards Stonehenge.  In yet another scenario the authors suggest that the Altar Stone might have been ice-rafted through the Strait of Dover following one or another of the envisaged mega-floods, and then dumped somewhere on the south coast of England.  That's a remote possibility, but before taking it too seriously we need to know much more about pre-Devensian glacio-isostatic adjustments and sea-level changes.

In summary, this is a very strange article.  While I welcome the fact that some authors are at least taking the idea of long-distance glacial erratic transport seriously, the scenarios examined in the article all involve the human transport of a large bluestone monolith -- the Altar Stone.  I'm still highly sceptical about that, and I think that the authors here have accepted far too easily that the Altar Stone did indeed come from the far NE of Scotland.  I do not think that has been proved. 

Clarke and Kirkland have rushed into print far too early.  Their sampling and the use of surrogate samples suggests substantial bias.   If I am to be convinced by their provenancing, I would like to see the lead authors of this piece get out into the field, collecting samples from many ORS locations in various parts of Scotland, specifically for the testing of their hypothesis.  Once they have done that, and published their test results, I might be prepared to abandon my scepticism about the quality of their work.

See also Mike Pitts, who compounds the confusion:

https://mikepitts.wordpress.com/2026/06/05/stonehenge-altar-stone-glaciers/

Nordvestfjord Adventure 1962

Scottish erratics and the Irish Sea Ice Stream

 

Map of the northern British Isles, showing the main ice shed (ice divide) area which separated glacier ice flowing NW and W into the Atlantic and ice flowing broadly southwards in the Irish Sea Ice Stream.    Almost all of the reconstructions relate to the Late Devensian Glaciation.......

The traditional map of iceflow directions, based on Wright (1914)

The BRITICE-CHRONO map for 27,000 yrs BP -- ie near the peak of the Late Devensian Glaciation

Now this is interesting.  Geomorphological dilemmas are always interesting -- but they all get sorted out in the end........

It's all got to do with ice sheet summits and the positions of ice sheds.  I say "positions" because they are never static.  Shifts in snow accumulation patterns and drainage route efficiency happen all the time in modern ice sheets, as they did in the past. So during the course of a single glacial episode you may find that an ice shed (between diverging flowlines) may shift by 100 km or more.  And an initial  northward shift (for example) may be replaced later on by a similar or even greater southward shift.

See this article too:  "Flow pattern evolution of the last British Ice Sheet" by Anna L.C. Hughes, Chris D. Clark, Colm J. Jordan

https://nora.nerc.ac.uk/id/eprint/507185/1/Flow%20pattern%20evolution%20QSR.pdf

Hughes, A. L. C., Clark, C. D., & Jordan, C. J. (2014). Flow-pattern evolution of the last British Ice Sheet. Quaternary Science Reviews, 89, 148-168. 

https://doi.org/10.1016/j.quascirev.2014.02.002

The dilemma of current interest relates to the presence of erratics presumed to come from the western isles of Scotland found along the coasts of Devon and Cornwall.  Paul Berry tells is that the famous pink granite erratic at Saunton has probably come from Gruinard Bay in Wester Ross.  That's north of the Isle of Skye and at the same latitude as the Isle of Harris -- on the eastern shore of the Minch, which was (according to current wisdom) one of the great northwards ice discharge routes in the Late Devensian Glaciation.  That's 200 km north of the assumed Late Devensian ice shed position.  I have been reminded of this dilemma by a recent suggestion from Prof Peter Kokelaar that he has seen a number of glacial erratics on the Gower that have come from the Western Isles -- well to the north of the supposed ice divide.

Almost all of the ice shed positions described in the literature show that they lay on a line approximately joining Belfast to Glasgow -- across the North Channel and running NNE --SSW.  Some reconstructions show an ice shed running NE-SW along the Southern Uplands of Scotland, and some show an ice divide approximately on the southern part of the Isle of Arran and running across the tip of Kintyre -- but always the assumption is that the ice from the ice shed flowed across Islay and the Malin Shelf and westwards out into the Atlantic.  I have seen no Devensian reconstructions showing a broadly southward flow of ice through the North Channel.  

Some interesting work on erratic distributions, from Veness et al, shows us that erratic dispersal tracks can be quite different during the advance and retreat stages of the same glacial episode.  This shows up in the maps of Shap erratic distributions and the complex distributions from the Loch Fyne source.  It's clear that the Irish Sea Ice Stream can have carried Shap granite erratics and erratics from the northern end of Loch Fyne hundreds of kilometres to the south.  We should not be surprised by this, in view of the relative abundance of Ailsa Craig erratics in Pembrokeshire and Gower.

See this:
Modelling erratic dispersal accounting for shifting ice flow geometries: A new method and explanations of erratic dispersal of the British–Irish Ice Sheet
R. L. Veness, C. D. Clark, J. C. Ely, J. L. Knight, A. Igneczi, S. L. Bradley,  15 May 2025

https://doi.org/10.1002/jqs.3720

https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3720

See also:  https://brian-mountainman.blogspot.com/2023/01/the-distribution-of-shap-granite.html

Bearing in mind that most far-travelled erratics will have followed zig-zag routes over the course of several glacial episodes, how far to the north might the ice divide have been located during Wolstonian and Anglian glaciations, and possibly even further back in time?

Well, if we look at landscapes rather than glacial deposits, it's clear that southward-flowing ice has played a powerful role in landscape formation in the southern part of the Western Isles.  Loch Fyne itself occupies a long and well defined glacial trough cut by ice flowing broadly southwards.  The Sound of Jura was also probably a glacial transport route.  So too the Firth of Clyde.  So too Loch Awe.  The Firth of Lorn and Loch Linnhe, following roughly the route of the Great Glen Fault and separating the North West Highlands from the Grampian Highlands, are more difficult to interpret because of the powerful structural influences at play; but it does look as if this elongated deep trough once carried ice flowing south-westwards.

So maybe, in trying to explain how erratics from the Western Isles found their way into the path of the Irish Sea Ice Stream -- and were then carried away far to the south -- we have to look at a very long history of glacial episodes, with some entrainment and transport related to local glaciations of the Scottish Highlands (involving local valley glaciers and outlet glaciers from the Scottish Ice cap, and other episodes of erratic transport related to glacial maxima and the work of the British and Irish Ice Sheet.  Sequence of events still to be worked out.......

There are two further matters to be considered:  isostatic and eustatic interactions, and changes in oceanic circulation which can be related to glacier expansion and contraction. These are important if we are to get to the bottom of the "ice rafting" issue.

The ice shed area shown on the map at the top of this post was (at least in the Late Devensian) the area of thickest ice and therefore the area of greatest post-glacial isostatic recovery.  Raised beach ridges occur in many locations (for example near Loch Tarbert of the Isle of Jura) up to altitudes of c 40m.  The raised beaches on Rum and Muck occur up to c 30m, and the highest beach is found at Arisaig in Lochaber, at 45m asl. (Added 1st June 2026: Prof Ian Shennan reminds me that there is some doubt about this figure.)

Raised beach ridges at Loch Tarbert on Jura

Another raised beach sequence on Jura

Isolated raised beach remnants resting on an old rock platform near Glenbatrick on the south shore of Loch Tarbert, Jura.  (Oblique satellite image from Google Earth)

The most prominent raised beach ridges may coincide with short-lived RSL stillstands and minor advances of glaciers feeding from the Scottish Ice Cap -- but this sequence of events has still to be worked out.  It's believed that someof the pre-LGM glacier advances (in the period 35,000 yrs BP to 27,000 yrs BP) involved floating glacier snouts and short-lived calving episodes -- so there might have been some "ice rafting" of erratics as envisaged by some geomorphologists.  Sea level at the time was approxinately at -60m m -- so any erratics transported southwards cannot have been dropped on modern shorelines far to the south.

Even earlier, during the Early and Mid Devensian, there may have been many calving episodes involving Scottish ice tongues in the western fjords.  During these episodes thousands of erratics might have been carried broadly westwards from the Scottish Highlands and dropped in deep water -- available for future recycling.  

In any case, extensive southwards iceberg drift seems very unlikely, since the prevailing oceanic  current direction on the western coasts of Britain -- driven by the Gulf Stream and the North Atlantic Drift -- was broady northwards, not southwards.  Even if there was a weakening of the North Atlantic Drift and a reduction in the force of the westerly winds at the time of the Loch Lomond Stadial, and in esrlier expansions and copntractions of the Scottish Ice Cap, it is most likely that any icebergs carrying erratics into Scottish tidal waters will have melted and dropped their loads quite close to their places of origin, as happens today in the Greenland fjords.

Following the LGM, and the massive expansion of the BIIS and the development of the Irish Sea Ice Stream, we now know quite a bit about the Younger Dryas (Zone III) or Loch Lomond readvance.

The blue area on this map indicates the extent of the Loch Lomond Stadial in Scotland

Bickerdike, H.L., Evans, D.J.A., Stokes, C.R. and Ó Cofaigh, C. (2018), The glacial geomorphology of the Loch Lomond (Younger Dryas) Stadial in Britain: a review. J. Quaternary Sci., 33: 1-54.

https://doi.org/10.1002/jqs.3010

This brings us back to the matter of ice rafting and the Devon and Cornwall coastal erratics.  Could ice floes have carried some of them all the way from the Western Isles, through the North Channel and across Cardigan Bay at a time when relative sea level was more or less as it is today?  As indicated above, I can see no set of circumstances in which that was possible.  There are abundant dropstones and sand and gravel layers in the glacio-marine sediments on the bed of the Celtic Sea, but all are connected to the the advance of the Irish Sea Ice Stream ice front prior to 26,000 years ago and to its retreat between 26,000 and 20,000 years ago -- at a time when relative sea level was probaly around -130m.  Towards its outer edge the ice front was afloat, but that was at least 200km away from the tip of Cornwall.

The ice rafting hypothesis really is a non-starter.  So the "western Scottish" erratics must have been derived from very ancient glacial deposits, and they must all have had very complex histories of glacial entrainment and transport.

 

The bluestones and their "quarries" -- some forthright views from Peter Kokelaar

One of the figures from Peter's blog.

I have been following up some very interesting material relating to the glaciation of the Gower, and have looked again at Prof Peter Kokelaar's blog.  

https://kokelaargower.com/

It's a treasurehouse of field observations and new data, summarising the contents of his book called "All our own Water" and adding much new material.  There are two blog posts that are of particular interest:

https://kokelaargower.com/stonehenge/

https://kokelaargower.com/towards-stonehenge-the-anglian-glaciation-of-gower/

Many of the points made in Peter's posts are very similar to the points I have made repeatedly on this blog and in my published papers  -- but I had forgotten how forthright some of his language is! 

Quote: 

"Many people will be aware of a long-running, media-fuelled ‘debate’ regarding the delivery to Stonehenge of a suite of rocks – the so-called bluestones – most of which certainly originated in Pembrokeshire. I shall not engage with the negative elements of that ‘debate’, which rather uncompromisingly set human transport against glacial (erratic) explanations. I do, however, briefly explain what seems reasonable to believe and might just nudge the reader towards a possible half-way house....."

Most of Peter's critical scrutiny of the literature occurs in the article entitled "Stonehenge" -- and in spite of attempting great restraint, he cannot resist (and who can blame him?) some choice phraseology! On the bluestone debate he refers to "a jumble of confusing claims, counterclaims and manifest nonsense, with a good measure of misleading media hype thrown in....."

Quotes:
"..........the ‘debate’ has involved somewhat alarming instances of serious subjectivity and media hype unlikely to promote the lay person’s trust in ‘expert opinions and methods’, probably to the contrary."

".........when all of the claims for human transport are stripped away for being without any foundation, ice is the only obvious agent, even if the last reach of it is not obviously or unequivocally recorded. Largely because of the media hype, which persistently favours the “extraordinary human endeavour”, ice transport currently gets practically no mention (e.g., the BBC Countryfile on Stonehenge of 14th December 2025 and the Channel 5 “Stonehenge: Secrets of the new stone” of 3rd March 2026), but that is misleading. Ice transport warrants the light of reasonable consideration."

"........we will recall some of the media’s misdirected presentations of the human transport view as if it was well supported by archaeological or scientific facts. This has been a bizarre distraction at least, if not damaging."

"There has been a strong tendency to interpret all fragments of monolith stone types as reflecting ‘dressing’ and accidental distribution by human hands and thus to refer to them as ‘debitage’. This might be justified in the vicinity of the monuments, but the interpretation potentially involves circular reasoning."

"Motivation for the “stupendous feat” in human transport has always been a problematic weakness in the case, earlier attributing fantastic reasons like magical powers or sonic properties to the stones, or later mistakenly claiming reverence for them in sites of previous circles that then acted as sources for removal and transport (e.g., Parker Pearson et al. 2021). Fantastic claims, including inference of active quarrying to produce the stones at rock outcrops that are actually typical of natural jointing, weathering and collapse, are now, with sensible geology and geomorphology, and with robust geochemical evidence, thoroughly debunked. So, no quarries and no uprooting of former monuments (Bevins et al. 2022; John et al. 2015; John 2025)."

On the Boles Barrow spotted dolerite boulder: "However, the range of convoluted and contradictory claims made through time, not helped by the boulder being temporarily ‘lost’ and including the suggestion that it was transported to Stonehenge and then stolen for a garden ornament (subsequently refuted), is astonishing and mind-numbing."

"There is not a shred of evidence that humans transported any ‘bluestones’ all the way from Pembrokeshire to Stonehenge. The human-transport view was initiated with HH Thomas (1923) and thereafter centred on the lack of spotted dolerites in the erratic trail beyond Pembrokeshire, plus the seeming absence of evidence of ice movement onto Salisbury Plain. The supposed quarries and previous-monument sources have been disproved and the bizarre embellishment concerning the transport by cattle similarly is unwarranted."

On the so-called bluestone quarries: "........nothing about those virtually pristine igneous rock outcrops could lead a field geologist to consider them anything other than naturally formed, including their aprons of fragmental debris. .......... To ‘inform’ the BBC-viewing public that quarrying by humans broke out the pillars ready for transport at the very summit of a perfectly natural outcrop, is ridiculous "

"There are hundreds of perfectly natural outcrops of jointed dolerite like this dotted throughout upland Britain, some quite nearby too, and of course also abroad. Surely many thousands of years of freeze-thaw mechanical break-up cannot be overlooked? From this nonsense, ignoring simple natural processes and geology and by implication suggesting ancient quarry sites all over the country, there apparently can have been no scientific-editorial oversight and advice for the archaeologist(s). Gross mis-pleading like this, on a television channel that prides itself in distinguishing the truth, surely undermines simple enquiry and learning, undermines the credibility of actual experts, and, given the n-fold repetition of the BBC programme, is effectively misleading a host of people. Thankfully numerous sensible people have taken issue with the programme and the ‘quarries’ have been debunked and abandoned amongst aficionados, although the BBC continues the promotion."

"Despite objections made regarding the ‘quarries’ (e.g., John et al. 2015), there was no retraction while the focus shifted to removal and transport to Stonehenge of stones from pre-existing monuments (Parker Pearson et al. 2021)."

Regarding "The Lost Circle" TV programme: "...........the whole programme, with its intense and dramatic revelations of quarrying and removal from a former stone circle, proved to be spectacularly wrong. One might say that hindsight is a wonderful thing, but contemporary expert advice was always available and ignored, and the media show on what is known to be a topic of wide interest was an information disaster."

"The nonsense carried on. After the Altar Stone saga in 2024, in 2025..... there came another remarkable gem of mis-information." Regarding the claims made about a cattle tooth: ".......nothing supports these contentions, which are false and are sheer hype."

"The claim that the cow-tooth findings add to confirmation of the “theory” that cattle were involved in transport of the megaliths is udderly ridiculous. Apart from confusing theory and hypothesis in this media hype, the unjustified claims were disturbing as they came from the Press Office of the British Geological Survey; no sane geologist would support them. Actually, the original scientific report of the cow-tooth findings, in contrast to the hype, was quite reserved, acknowledging limitations to interpretations that should be borne in mind. What is it then, really, that causes decent science to be so compromised in the media? There certainly is cavalier ignorance on the part of media producers, whose driver seems to be promotion of viewing figures or sales… Honesty about the issues might have been more interesting and more stimulating of genuine interest… Some of the media nonsense is arrogant and insulting."

So there we are then......... I am clearly not alone in expressing concern about the pseudo-science being fed to the world by the the most vociferous part of the Stonehenge establishment.

Revisiting the GBG (Greatest British Glaciation) of western Britain

Suddenly everybody seems to be interested in the erratics on the shores of the Bristol Channel, which is great.  The above map, which I think I first published in 2017, becomes very relevant indeed.  There are of course many similarities between what I refer to as the GBG and the LGM (Last Glacial Maximum -- Late Devensian):

I'm dithering on the precise dating of the GBG  it might have been the Anglian (MIS 12) or it might have been one of the phases of the Wolstonian (MIS 6).  Then again, the maximum ice extent might  not be represented by a single ice edge -- if such a thing might indeed have been discernible on the ground surface.  The outer limit of this glaciation might have occured in different sectors at different times -- in other words there might have been asynchronous oscillations.

In any case I am increasingly convinced that the ice reached the Fremington / Croyde / Saunton area on at least two occasions.

Interestingly enough, in my map for the GBG I show local icecaps on Dartmoor, Exmoor and Bodmin Moor as being incorporated into a landscape dominated by glacier ice, permanent snowfields and intermittent snow-covered terrain.  And on my model glacier ice could have carried the Ramson Cliff erratic broadly northwards from a "Cornubian outcrop" as suggested by Daw, Madgett and Ixer......

The main problem with that is that it implies a dynamic northward flow of ice from the Dartmoor ice cap as envisaged by Prof David Evans and others at a time when there was no competing ice flow from the N or NW.  See this:

https://brian-mountainman.blogspot.com/2012/06/dartmoor-ice-cap.html

The glaciation of Dartmoor: the southernmost independent Pleistocene ice cap in the British Isles
David J.A. Evans, Stephan Harrison, Andreas Vieli, Ed Anderson
Quaternary Science Reviews 45 (2012) 31-53

https://www.researchgate.net/publication/258707211_The_glaciation_of_Dartmoor_The_southernmost_independent_Pleistocene_ice_cap_in_the_British_Isles

https://www.torsofdartmoor.co.uk/tor-page.php?tor=slipper-stones

David and his colleagues suggest that the ice cap was thin and sluggish, and probably incapable (even at the time of its maximum extent) of deep erosion and significant erratic transport.  The northward known extent of the ice cap was at c 460m asl, near the Slipper Stones in the West Okement Valley --  roughly halfway between Meldon Reservoir and the high peaks of Yes Tor and High Willhays.  That's almost 50 km from the Croyde-Saunton area.  And therein lies the problem.........  at the time of the GBG, the intervening area would have supported extensive connected snowfields, some of them permanent (in that they survived during the summer months) and some melting intermittently.  But we can see no glaciological scenario suitable for the transport of big epidiorite boulders.......  On the other hand David and his colleagues were referring to a Late Devensian ice cap on Dartmoor.  Might there have been a much larger, earlier glacier about which we currently know virtually nothing?  We have to admit that this is quite possible......

The other question which deserves attention is that of the parallel ice streams.  Geoffrey Kellaway suggested many years ago that there were several confluent  ice streams flowing into the Bristol Channel, including one carrying Scottish erratics and one carrying Welsh erratics.  I also explored this idea with Lionel Jackson in a 2009 journal article:

https://brian-mountainman.blogspot.com/2020/09/stonehenges-mysterious-stones.html

Nowadays I think I prefer the idea of a zig-zag movement of erratics over several glaciations. but we have not heard the last of this!

Could the Ramson Cliff erratic have come from Rosslare in SE Ireland?

In the discussion by Daw et al (2026) on the possible origins of the Ramson Cliff Boulder, there is a brief consideration of possible Welsh or Scottish sources, but no mention at all of the possibility that the erratic might have come from the coast of SE Ireland -- more specifically, near Wexford or Rosslare. That is a very peculiar omission, given that the petrological match between the boulder and the 'Rosslare Complex' appears to be far more convincing than the match between the boulder and the Cornubian Batholith rocks.

https://gsi.geodata.gov.ie/downloads/Bedrock/Books/Understanding_Earth_Processes_Rocks_and_Geology_Ireland/Chapter_02.pdf

THE ROSSLARE COMPLEX

The Rosslare Complex is divided into two major units; a group of grey gneisses, coarsely crystalline metamorphic rocks that are well exposed at Kilmore Quay, and a group of dark-green metamorphosed igneous rocks called amphibolites that are seen around Rosslare Harbour and Greenore Point.

(Note: the modern term "amphibolite" is applied to the rocks that are otherwise known as "epidiorite")

The gneisses typically have a banded appearance, in which pale-grey bands of the minerals quartz and feldspar are separated by darker bands rich in mica. These rocks are interpreted as originating as sediments, deposited as a succession of greywacke sandstones and interbedded mudstones. Several periods of metamorphism, under high temperature and pressure conditions deep in the crust, produced the present-day gneisses. In places, thin sheets of granitic composition were injected parallel to the banding in the gneisses. These suggest that particularly high temperatures caused partial melting of the sediments and re-injection of the melted rock as granite.

The metamorphosed igneous rocks are rich in a dark-green mineral called amphibole. They are the metamorphosed equivalents of gabbro and diorite. Although the relationship is not clear, these igneous rocks probably intruded the sedimentary rocks that later became gneisses.

Deformation and metamorphism of the Rosslare Complex were caused by the Cadomian Orogeny of Late Precambrian age, which also affected rocks in southern Britain and northern France. New minerals that grew in the rocks during metamorphism have been dated as 620 million years old, but the gneisses and amphibolites were both already in existence before this time and so were produced by an even earlier metamorphism.

A literature search throws up the point that there are significant greenstone and altered basic complexes in the Wicklow or Wexford areas that align with the path of the Irish Sea Glacier.  Other suggested possibilities are the St David’s area or part of the Gwaun Valley, both of which have basic igneous bodies, though their specific petrography would need to be matched to the erratic. The Bristol Channel Floor has known submerged outcrops of older Variscan basement which might also provide a match, though these are harder to sample.  But for the moment, let's go with Ireland..........

The unconsidered Rosslare case (~600 Ma): The Rosslare Complex (Wexford) is dominated by Cadomian/Avalonian zircon ages, with major peaks around 600–620 Ma. These zircons frequently show metamorphic "resets" or rims from the Ordovician (~480 Ma), reflecting the complex tectonic "squeezing" this region underwent.

The preferred Cornubian case (~290 Ma): Local greenstones associated with the Cornubian Batholith were formed or heavily influenced by the Variscan Orogeny. Their zircon populations are dominated by Early Permian ages.

The petrological match between the Wexford (Rosslare Complex) rocks and the Ramson Cliff erratic is much superior to the Cornubian match because it provides a complete explanation for the rock's ancient, stressed, and complex history—features that are largely absent or localized in the Devon greenstones.
While Daw et al  (2026) favour a local source to support a human-transport theory, the following four petrological reasons demonstrate rather convincingly why Wexford should be considered as a likely provenance:

1. High-Grade Metamorphic Fabric
The Ramson Cliff erratic is a foliated epidiorite/amphibolite, indicating a rock that has been completely structurally reorganized.  In Wexford, the Rosslare Complex is defined by its high-grade, ancient metamorphic rocks. Units like the Greenore Point Group (very close to Rosslare Harbour) consist of strongly foliated amphibolites that were "squeezed" during multiple major mountain-building events. This explains the deep-seated gneissose texture of the rock.  In Cornubia, most Devon "greenstones" are lower-grade greenschists. They are typically massive (lacking a strong fabric) or only weakly sheared. Finding a highly foliated amphibolite in Devon requires searching for very narrow, specific contact zones.

2. The Polyphase Tectonic Story
The erratic shows signs of multiple metamorphic events, with relict minerals overprinted by secondary ones. In Wexford, the Rosslare Complex shows a "polyphase" evolution. It underwent high-grade metamorphism in the Precambrian (~620 Ma), was overprinted in the Ordovician (~480 Ma), and was stressed again in the Variscan. This "messy" internal mineralogy seems to give a match for the erratic’s apparently complex history.  In Cornubia, the Devon greenstones generally show a single, clear Variscan metamorphic event related to the intrusion of the granites. They lack the "deep time" complexity and multiple layers of history found in the Irish basement.

3. Zircon Age Heritage
Petrological identification includes the age and condition of the mineral grains. In Wexford the Rosslare rocks provide a Precambrian (~600–620 Ma) signature. These zircons are often rounded and pitted, matching the "battered" appearance of the crystals in the erratic.   In Cornubia the rocks in question are primarily Variscan (~290 Ma). Even when they contain older cores, their primary "internal clock" is significantly younger.   The degree of recrystallization in the erratic appears more consistent with a rock that has survived 600 million years of history.

4. Geochemical Deep Fingerprints.

Trace element plots are used to identify the original tectonic setting of the parent magma.  In Wexford, the geochemistry of Rosslare's dark gneisses shows tholeiitic signatures consistent with ancient rifting or back-arc basins. This provides a distinct "DNA" that matches the erratic's trace element ratios.  In Cornubia, in contrast, while also tholeiitic in part, the Devon greenstones  show a stronger "continental arc" or "within-plate" alkaline influence, which creates a subtly different slope on
discrimination diagrams.

But, I hear you say, what about the lack of epidote in the Ramson Cliff Boulder, which Daw et al use as a key part of their analysis?  They say that if the boulder had epidote then a western British source would be feasible, but because it is apparently lacking in the one thin section analysed, then the Cornubian source is the only realistic alternative.

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Quote from Daw et al, p 15-16:  Other than possible very fine-grained clinozoisite epidote group minerals are absent as are other distinctive secondary minerals including quartz, serpentine minerals, analcime and calcite. Their absence eliminates many altered basic rocks that crop out in western Britain.

.................The alteration of this rock,  notably the lack of epidote, is incompatible with it coming from South Wales (including the Preseli Hills altered dolerites), hence it cannot be a South Welsh 
glacial erratic. Similarly, the absence of analcime and  calcite eliminates other more northern Welsh localities. 

In addition, the petrography and metamorphic grade eliminate it from having a Scottish origin within the British Tertiary Igneous Province despite glacial erratics from that province (but only from the nearby Lundy Granite) being present on nearby Devon beaches. The known Scottish erratics found in  more southern English sites are all petrographically highly distinctive rocks (hence their recognition) 
with characteristic primary and secondary mineral assemblages not recognised in the boulder.

=================

This is all very technical, and I am checking it out with Irish geologists.  Ixer (who wrote the petrographic description) seems to claim that epidote is always found in the altered basic rocks of South Wales, and that if the erratic hade come from North Wales it would have contained analcime and calcite.  He says that "petrography and metamorphic grade" rule out a Scottich origin -- but that is a very vague statement unsupported by hard evidence. If there is evidence, it should have been cited.   Also, I gather from Prof Peter Kokelaar that epidode is NOT ubiquitous in Caledonian Palaeozoic meta-basic rocks -- so to rule out Scotland as a possible source area on that particulat line of evidence would be unwise.  We are told by Ixer that the known Scottish erratics found in southern England are all "petrographically highly distinctive" -- but we are given no information to back up that claim.  The jury is still out.

But from the point of view of glacial geomorphology, a SE Ireland origin for the Ramson Cliff erratic makes perfectly good sense.  I know of only one other positively identified Irish erratic in the Bristol Channel arena -- namely the very hard 'white limestone' boulder found in glacial deposits at Court Hill which is widely assumed to have come from the Ulster White Limestone of County Antrim in Northern Ireland (Gilbertson and Hawkins 1978).  That provenance is entirey reasonable, given what we know about the ice movement directions of the Irish Sea Ice Stream during several glacial episodes.

Could ice have carried Irish erratics from the Rosslare coast out into St George's Channel for incorporation in the Irish Sea Ice Stream, and for transport up the Bristol Channel and onto the Devon coast?  The answer is YES.  That would not involve any provenancing gymnastics -- and is a much more likely scenario than that proposed in the latest article by Daw, Ixer and Madgett.

A provenancing link between the Baggy Point area and Northern Ireland would of course be supported by the biological content and geochemistry of the Fremington Clays and till exposures.  As reported by Gilbertson and Hawkins, Kidson, Stephens and many others, there are strong biological, geochemical and petrological 'markers' in the Fremington clay and till series that indicate that the deposits are not locally originated or derived, but are made of sediments brought in from the N, NW and W -- pointing to one or more incursions of Irish Sea glacier ice.  

Here are some of the maps with reconstructed ice directions in the Celtic Sea arena and the Bristol Channel.  Needless to say, the details are still being worked out -- not just for the older glaciations (Anglian and Wolstonian) but for the LGM as well.

One of my very old maps.  I have been playing with the idea of the Celtic Sea Piedmont Glacier for 60 years or more, and I still think it might explain a few features........

One of my more recent attempts to define the limits of the LGM in this area and the likely directions of ice movement at the time of  'peak glaciation'

One of the BRITICE maps, showing that at one LGM stage (or, more probably. during many stages) ice from the Irish Ice Cap flowed across Wexford and into the St George's Channel.  (Note that this map shows an ice-free corridor over most of Pembrokeshire -- a strange idea which is unsupported by hard evidence and which defies the laws of glaciology.)

POSTSCRIPT

No doubt we will hear more about the geological similarities / differences with regard to the Ramson Cliff amphibolite erratic and the metamorphosed gabbros and diorites of the Rosslare Complex.  But here is another useful contribution to the debate.  Paul Madgett has very kindly sent me through a photo of a large rounded boulder in a difficult location near Down End.  He says: 

 "..........it's on my listing of the larger local erratics in the 2nd edition of his "Cliffs of Saunton" booklet. As far as I am aware few others have even seen it, as it is very difficult of access and only at low spring tides - even then, for safety you need one of the more extreme low tides. Apart from the mention above, and in my 1987 paper, nothing has been published on it.  However, I was immediately struck by the tight folding of the gneissose banding, and thought of Carnsore Point.........."

As mentioned above, there are two rock "groups" in the Rosslare Complex -- the banded gneissses and the metamorphosed igneous rocks.  Could it be that we now see representative erratics of both types in the Croyde - Saunton area?

To repeat my earlier point -- we should not be surprised by the presence of erratics from eastern and south-eastern Ireland in the Bristol Channel arena.  Irish ice (ie ice from the Irish Ice Cap) flowed eastwards and south-eastwards on the western flank of the Irish Sea Ice Stream and added to its bulk. I would expect to find Irish erratics mixed with erratics from western Scotland, the Lake District, North Wales and West Wales on the Gower coast, the coasts of south Glamorgan, and the coasts of Cornwall, Devon and Somerset. 

See also: 

https://brian-mountainman.blogspot.com/2015/01/the-erratics-at-baggy-point-croyde-and_18.html

Six million views

 

An erratic boulder is a large stone that should preferably have

 been somewhere else.........

I have not kept my eye on the ball, but we have sailed through the six million mark.......  as I said when we went through the 5 million mark, a lot of hits nowadays come from AI bots.  But with AI, as with many otherc things, popularity breeds even more popularity, and the blog is now so well established that it is scanned all the time by bots looking for answers to a wide range of different questions -- ranging from glaciers to bluestones, and Stonehenge to Pembrokeshire and East Greenland to Iceland.   So I'll keep going as before, commenting on Stonehenge matters, scrutinising new publications, and contributing original new science on a range of landscape and Ice Age related themes.