Freshly quarried monoliths, or ancient glacial erratics?

One of the most bizarre features of the glacial transport / human transport debate is the insistence of the HT advocates that the Stonehenge bluestones are freshly quarried monoliths that just happen to be somewhat weathered.  Their narrative requires quarrying from special places  -- but of course there is no evidence at all that Rhosyfelin or Carn Goedog were "special places" in Neolithic times, and neither foliated rhyolite or spotted dolerite were ever used preferentially in West Wales by the builders of the megalithic structures.  And as for the evidence of quarrying, we all know that it is so thin that it cannot withstand scrutiny, as Dyfed Elis-Gruffydd, John Downes and I demonstrated in two papers in 2015.  (For a decade, these highly inconvenient papers have been entirely ignored by MPP and his associates.  Make of that what you will.)  Indeed, our careful analysis of the "quarrying features" showed them to be entirely natural and unexceptional.  The sedimentary sequences at the two sites, and the radiocarbon age determinations, also fail to demonstrate that there ever were obvious "quarrying episodes" in the time frame desired by MPP and his colleagues.

Now the narrative appears to incorporate other Neolithic quarries and other stone circles as yet undiscovered, at sites that are deemed  (by modern archaeologists) to have been sacred or special.  Fantasy rules, at every stage of the narrative.

The stone provenancing work by Ixer, Bevins and associated colleagues is interesting in demonstrating a "North Preseli" connection with Stonehenge, but it is a good deal less definitive than they would have us believe, and it tells us nothing at all about how boulders, smaller stones, cobbles and fragments of many different rock types may have travelled from A to B.  It is one of the most unfortunate features of this debate that the geologists from an early stage decided to side with the HT proponents and to promote the view that GT was impossible.  It is even more unfortunate that they decided to support the view that the bluestone monoliths were taken from Neolithic bluestone quarries rather than being collected as boulders from an erratic-strewn landscape.

So what about the Stonehenge bluestone monoliths?  As night follows day, they are obviously NOT freshly quarried blocks.  Some of them have been tooled and shaped, like the dolerites in the Bluestone Horseshoe, but to pretend that the other boulders, blocks and slabs were transported as targetted and freshly quarried blocks is to deny everything we know about weathering and erosional processes.  The facets, the abraded edges and the weathering characteristics all indicate glacial entrainment, transport in a dynamic sub-glacial or englacial environment, and long exposure to weathering processes.  By this I mean tens of thousands of years at the very least.

It is disingenuous of the HT brigade to pretend that the rounding and weathering of the Stonehenge bluestones might have occurred over the last 5,000 years or so, and that in scale and character it is similar to that displayed on rock surfaces at Rhosyfelin and Carn Goedog and on the surfaces of the Stonehenge sarsens.  In arguing that way, they are making my point for me, since the bedrock surfaces, and the surfaces of the sarsens, are the results of very long exposure to the elements.  HH Thomas accepted this point a century ago, when he argued that the Stonehenge bluestones were not quarried but picked up from an erratic scatter somewhere on the south side of Preseli.

It is really rather weird that the earth scientists who belong to the "group of eleven" who have so recently attacked me and my work on the Newall Boulder should apparently be so naive about the physical processes that operate on rock surfaces.  They claimed that the Newall Boulder was simply the broken off top of a rhyolite monolith which has subsequently suffered from a certain amount of weathering.  As I have demonstrated, it is a great deal more complicated than that, with both weathering and erosional features demonstrating a complex transport and emplacement history in which glacier ice almost certainly played a part. The apparent lack of clear glacial striations on the boulder cannot be used as part of an argument against glacial transport, as every glacial geomorphologist knows.

As I have indicated in my recent publications, the shapes and surface characteristics of the Stonehenge bluestones are entirely consistent with glacial entrainment, glacial transport, dumping in locations still to be determined, and then long exposure to atmospheric weathering processes.  The boulders might even have been entrained, transported and dumped on multiple occasions.  There is a vast literature on glacially transported clasts, as demonstrated by stone shape, sphericity, surface roughness and other measures.  See the work of Prof David Evans and many others.  These are quotes from my 2024 Newall Boulder paper:

https://doi.org/10.5194/egqsj-73-117-2024

Clasts occupy a wide range of positions in mobile subglacial till (Evans et al., 2016, 2018). They are subject to complex transport histories that involve variable amounts of dragging, rolling and lodging, during which they are subject to surface modification through inter-clast collisions and contacts. Any single clast may be reworked numerous times during successive glaciations.  Because clasts will tend to take the line of least resistance to the flow of the surrounding deforming till matrix, facetted and bullet or wedge shapes are developed. Whenever a clast is disrupted from its lodged position, it can be subject to fresh fracturing, gradually changing its overall shape to one of a block (Boulton, 1978; Benn and Evans, 1996; Evans, 2018).  Although not all glacially transported clasts display such bullet or flat-iron shapes, such an appearance is diagnostic of significant subglacial transport (Evans, 2018; Evans et al., 2006).

.............  Overall, the surface characteristics of this boulder suggest that it is a discrete erratic that has been  transported for much if not all of the time in a subglacial position (Benn and Ballantyne, 1994; Lukas et al., 2013; Benn and Lukas, 2021).

It should be noted that most of the 43 bluestone “monoliths” at Stonehenge are not elongated elegant pillars (as portrayed in most reconstructions) but heavily abraded unremarkable boulders and elongated slabs. There are clearly defined facets, some of which are rough and others smooth. There are few sharp edges. The stones would not be out of place in the morainic accumulations around any glacier snout in the world (Benn and Evans, 2010, and references therein). They look like glacial erratics, and they are heavily weathered as a result of prolonged exposure (Fig. 14). On some weathered surfaces segments of the crust have peeled away and have been lost. It is probable that Stonehenge was built where the stones were found, as suggested by Judd (1903) and Field et al. (2015), and this is supported here by the preliminary analysis of the Newall Boulder.

In addition, I have done post after post on this blog, making the point that most of the Stonehenge bluestones are not pillars, and neither are they sharp-edged quarried blocks:

https://brian-mountainman.blogspot.com/2021/02/the-bluestone-pillar-myth.html

If they were quarried, they would look like the blocks in these wondrous artists impressions. The upper one was drawn to illustrate the Rhosyfelin "quarry" with the approval of MPP, for a Stonehenge exhibition in Belgium in 2018.

Whatever the flights of fancy and scale distortions might have been in these reconstructions, the detail relating to the extracted block edges is quite correct:  they are always sharp and clearly defined.

https://brian-mountainman.blogspot.com/2018/10/the-quarrying-roadshow-hits-belgium.html

Next, let's look in more detail at the methods employed by geomorphologists in defining clast shapes.  In my paper on the Newall Boulder I referred to the scheme developed by Powers (1953):

Powers, M. C.: New roundness scale for sedimentary particles, J. Sediment. Res., 23, 117–119, 1953

https://doi.org/10.1306/ D4269567-2B26-11D7-8648000102C1865D.

Other schemes are available. There is a vast literature, but  roundness / sphericity scales like this are frequently employed in geomorphology and petrography:

(after Krumbein and others)

The shape of blocks, pillars and slabs extracted from bedrock outcrops will vary according to fissures and fracture patterns within the rock; some rocks are massive and coherent, with few internal weaknesses, while others (like shales, mudstones and maybe even foliated rhyolite) will break down into slabs, sheets and plates such as we see on slate quarry spoil heaps.  We must also take account of surface roughness in assessing clast origins.  In general, quarried blocks and slabs will be classified, on this scheme, as angular, on the left edge of this diagram.  But the stonehenge bluestones occupy quite different positions on the diagram, mostly in roundness categories 0.7 (rounded) and 0.9 (well rounded) but with some fresher and rougher facets such as those observed on glacial erratics..  This is not a consequence of weathering, but an indicator of travel distance, breakage and erosion.

Finally, there are three pieces of evidence that allow us to reject the quarrying hypothesis without further ado.

1.  If Parker Pearson and his colleagues are to be believed, the rounding and abrasion which we see on the standing bluestones today are the result of "weathering" in the time that has elapsed between stone extraction and the present day.  That involves a fundamental misunderstanding of the word "weathering", but we'll let that pass for now.  More to the point, all of the excavations which have revealed fallen and buried bluestones suggest that they are just as abraded, rounded and weathered below ground as above ground, with some rougher surfaces on facets such as we see on glacial erratics close to current glacier fronts. That means that (with the exception of a few worked stones) their shapes were already established prior to erection in the stone settings.  That means they were not installed as fresh quarried blocks, but gathered up as weathered and abraded boulders from the landscape as suggested by HH Thomas, Kellaway, Thorpe et al, and Field.  The MPP claim that the bluestones were pre-used in lost stone circles does nothing to support the quarrying hypothesis.

The "proto-orthostst" at Craig Rhosyfelin.  The sediments that have accumulated around and above the slab since the Early Bronze Age are clearly displayed.

2. The famous 8-tonne proto-othostat found at Rhosyfelin and flagged up as "intended for Stonehenge" was discoverd through radiocarbon dating to have been emplaced during or later than the Bronze Age.  Some charcoal found beneath it was radiocarbon dated to the Early Bronze Age.   So it cannot possibly have had anything to do with Neolithic quarrying at the site.  But because it is a rockfall slab which has crashed down from the higher part of the rock outcrop, and because it has been there for more than 3,000 years, its condition is of considerable importance. I have analysed it in detail:  

https://brian-mountainman.blogspot.com/2015/05/the-famous-rhosyfelin-proto-orthostat.html

https://brian-mountainman.blogspot.com/2012/11/rhosyfelin-is-it-quarry-site.html

It is very fresh in its appearance, with very little rounding off of sharp edges or other weathering traces in spite of exposure to the atmosphere and to other processes during and after burial by slope deposits. This reinforces the view that the Stonehenge bluestones carry surface features that are not just 5,000 years old but are the result of tens or hundreds of thousands of years of exposure.

Rock surfaces on the Pentre Ifan cromlech.  It is now suggested that the pillars and capstone were not buried for any great length of time.  After thousands of years of exposure to weathering, the smoothed and abraded faces, and those damaged by fracturing, are remarkably fresh.

3.  It is instructive to  examine the surfaces of the capstones and supporting pillars of Pembrokeshire cromlechs like Pentre Ifan, Carreg Samson and  Carreg Coetan Arthur.  The stones used by the builders were all large erratics of rather local origin and collected in the neighbourhood.  The stones are weathered but in places seriously damaged by fracture scars -- in other words, the features attributable to glacial processes and periglacial modification (frost damage) are beautifully preserved.  These cromlechs are approximatelt the same age (or maybe somewhat older) as the bluestone stone settings at Stonehenge.  Over 5,500 years or so of exposure, there has been weathering, but there is no sign at all of weathering on the scale which Bevins et al (2025) require for the creation of the facets and smoothed surfaces of the Newall Boulder.

To sum up, the bluestone quarrying hypothesis is not worth the paper it is written on, and neither is the contention that smoothed rock surfaces are the result of post-Neolithic weathering processes. 

 

The Newall Boulder -- not just weathered, but eroded

In one media piece after another, over the past couple of weeks, on the matter of the Newall Boulder, we have seen statements like this:

Prof Bevins and his team said most of the characteristics cited "could be simply generated by surface weathering".

.........the new research asserts that surface markings previously believed to be glacial abrasion are more likely the result of natural weathering or ancient human handling.

.......wear patterns cited in previous studies as resulting from glacial movement could have actually been caused by natural weathering.

Bevins and colleagues suggest the marks on the stones were not signs of abrasion by the glacier, but were made by human hands coupled with general surface weathering instead.

This is all very weird, and suggests that assorted senior academics do not know the difference between weathering and erosion.  Very strange, since this is one of the things that a student of O level Geography or Geology would be expected to know.  For the record, "weathering" is the term used to cover the in situ breakdown of rock surfaces as a result of physical and chemical processes.  In contrast "erosion" incorporates the movement or transport of material away from its original location, and the use of tools (sand, gravel and larger clasts) in lowering the rock surface.  There are many erosive processes, but abrasion is one of the most important, involving the grinding away of a surface of relatively soft material by ongoing contact with relatively harder "tools".  We might call it the sandpaper effect.  

I cannot imagine why they thought this necessary, but the eleven authors of the recent Newall Boulder tirade appear to be determined to avoid any mention of erosion in their press releases and statements to the media.  So they pretend that the surface of the boulder incorporates some structural elements (describing it as a "joint block" on which all the surfaces coincide with fracture planes) but where the detailed surface characteristics are the result simply of surface weathering.

This is  a serious misrepresentation of the situation. I stand by everything I said in my detailed analysis of the boulder surface.  One face is a fault-controlled feature with slickensides, and some of the other distinct facets may also coincide with joints or other internal weaknesses, but they are clearly abraded, and cannot be explained away as the results of weathering porocesses alone. There are also percussion fractures and fracture scars, some of which might be related to human interference.  The chatter marks are best explained by reference to subglacial processes during ice transport.  There are some slight scratches, but I have refrained from describing them as genuine striations or grooves.  In my paper I describe the weathering features as well.  They are quite complex, but quite distinct from the features associated with erosional history.

For those who seem to be ill-informed on these matters, I can recommend a useful tome, the cover of which I reproduce below.  Other texts are also available.

The literature:

John, B. S. 2024: A bluestone boulder at Stonehenge: implications for the glacial transport theory,
E&G Quaternary Sci. Journal 73, 117–134,

https://doi.org/10.5194/egqsj-73-117-2024

Bevins, R. E., Ixer, R. A., Pearce, N. G., Scourse, J., and Daw, T. 2023: Lithological description and provenancing of a collection of  bluestones from excavations at Stonehenge by William Hawley
in 1924 with implications for the human versus ice transport debate of the monument’s bluestone megaliths, Geoarchaeology, 38, 771–785, 

https://doi.org/10.1002/gea.21971, 2023

Richard E. Bevins, Nick J.G. Pearce, Rob A. Ixer, James Scourse, Tim Daw, Mike Parker Pearson, Mike Pitts, David Field, Duncan Pirrie, Ian Saunders, Matthew Power, 2025.  The enigmatic ‘Newall boulder’ excavated at Stonehenge in 1924: New data and correcting the record,
Journal of Archaeological Science: Reports, Volume 66, 2025, 105303,
ISSN 2352-409X,

 
https://doi.org/10.1016/j.jasrep.2025.105303

Victorian gifts: new insights into the Stonehenge bluestones
Rob Ixer, Richard Bevins, Nick Pearce, and David Dawson explain more. 2022.
CURRENT ARCHAEOLOGY, AUGUST 29, 2022, 5 pp

https://the-past.com/feature/victorian-gifts-new-insights-into-the-stonehenge-bluestones/

Streamlining, Blidö, Sweden

 

 

Nice pic from one of my kayaking trips this summer.  There is not much doubt in this area about the direction of ice movement -- all the features associated with glacial erosion point to ice movement pretty well exactly north to south......

The shortcomings of the human transport hypothesis

"Who ordered this thing? Anyway, what's it for? I reckon it will bring us far more trouble than it's worth...."

Since some people are apparently celebrating a great victory for the human transport theory in the Bluestone Transport Stakes, let's just remind ourselves that celebrations are a little premature....

1.  There is no sound evidence from anywhere in the British Neolithic/Bronze Age record of large stones being hauled over long distances for incorporation in a megalithic monument (Thorpe et al., 1991). Many of the claims of long-distance haulage ignore the evidence of glacial transport routes for large erratics; but some large stones might have been moved short distances prior to erection. And it is self-evident that stones were moved about in the Stonehenge area during building work.

2.  Field observations show, consistently, that the builders of Neolithic monuments across the UK simply used whatever large stones were at hand (Burrow, 2006). The builders were pragmatists and opportunists, and they were not stupid. Thus said Stephen Briggs.

3.  If special or sacred stones were being transported to Stonehenge, it is vanishingly unlikely that they would all have been collected in the west, to the exclusion of all other points of the compass (John, 2018a).

4.  There is no convincing evidence either from West Wales or from anywhere else of bluestones (for example foliated rhyolite or spotted dolerite) being used preferentially in megalithic monuments or revered in any way (Darvill and Wainwright, 2016). 

 
5.  If long-distance stone haulage was an “organised activity” for the builders of Stonehenge, it is noteworthy that there is no evidence of the development of an appropriate haulage technology leading up to the Late Neolithic and a decline afterwards. In other words, there is no sign of any diffusion of innovation (Rogers, 2003).

6.  The evidence for quarrying activity in key Preseli locations is questionable (John et al., 2015b). No archaeological or cultural links have been established between Stonehenge and the proposed “quarries” at Craig Rhos-y-felin and Carn Goedog.

7.  The sheer variety of bluestone types argues against human selection and transport. There cannot possibly have been multiple “bluestone monolith quarries” scattered across West Wales (Thorpe et al., 1991).

8.  No physical evidence has ever been found of ropes, rollers, trackways, sledges, abandoned stones, quarry worker camps or anything else that might bolster the hypothesis (Kellaway, 1971). Bevins et al (2025) might argue that these thngs were ephemeral and were unlikely to survive for 5,000 years or more -- but this argument is no more convincing than mine when I say that ancient glacial deposits might exist, degraded and still undiscovered....

9.  Experimental archaeology on stone haulage techniques (normally in “ideal” conditions) has done nothing to show that our ancestors could cope with the sheer physical difficulty of stone haulage across the heavily wooded Neolithic terrain of West Wales (characterised by bogs, cataracts, steep slopes and very few clearings) or around the rocky coast. Burl (2007) made this point forcefully, and it remains forceful today.

10.  No convincing evidence has ever been found of a “proto-Stonehenge” in West Wales, built of assorted local stones that were dismantled and taken off to Stonehenge. Mike Parker Pearson's claim that a “giant stone circle” at Waun Mawn in Mynydd Preseli was the source and the inspiration for Stonehenge has been criticised by Darvill (2022) and others and has now been abandoned (Bevins et al., 2022).


There are other problems too, of which more anon.........

According to the Daily Mail......

Photography as a substitute for science.......

 https://www.dailymail.co.uk/sciencetech/article-14928191/Stonehenge-mystery-SOLVED-boulder-transported.html

Shock!  Horror!  Stonehenge mystery finally SOLVED!   For the first time this month......

Note the capital letters.

So if it's in the Daily Mail, it must be true.  This time, the truth seems to be that the glacial transport theory is dead.  Not so long ago it was the human transport theory that was dead.  The truth does not last long in fhe media.  But we knew that already.

Anyway, the paper -- like assorted other media outlets -- has picked up on the latest press release from Bevins et al (2025), issued in a feverish attempt to dismiss my work on the Newall Boulder and to prove that the glacial transport theory is dead.  Hmmm.  As Mark Twain might have said, reports of its death have been grossly exaggerated.........

Here are a few thoughts on the newsaper article -- and by implication, on the linked press release.

At the outset, we see this claim:  Bevins et al concluded that "there is no evidence to support the interpretation that it (the Newall Boulder) is a glacial erratic.".  That is an absurd claim.  "Evidence" is defined as facts or information brought forward to support or refute a claim, idea or hypothesis.  As a matter of fact there is abundant evidence in the literature in support of the glacial erratic interpretation.  Whether Bevins et al support it or reject it is another matter entirely.  If they believe that the evidence is unconvincing, that is what they should have said.

As is already apparent, I happen to find the evidence presented in their latest paper defective in a number of respects, as I will shortly explain. They should accept that with good grace.

The Newall Boulder (NB) is a precise match for the unique characteristics of rocks from Craig Rhosyfelin.?  No it isn't.  For a start, it looks different, which explains why it has been described by other geologists as an "ignimbrite" and as a strongly welded acid vitric tuff.  The "matching" presented in the paper by Bevins et al (2025) involves a highly biased and selective presentation of evidence, and the geologists involved have still not demonstrated that the characteristics of the Rhosyfelin foliated ryolite are totally unique to that site, since the density of the sampling points and the range of their fieldwork in the area are far from adequate.

There are columns of foliated rhyolite at Rhosyfelin which have bullet-shaped or rounded tops similar to that of the NB?  Well, there is very little in the way of columnar jointing at the site.  And rounded and abraded surfaces on the higher parts of the crag are replicated on almost all of the tors of Preseli, and are interpreted by me and other geomorphologists as indicative of glacial or fluvioglacial abrasion in the past.  This tells us nothing about the provenance of the boulder, and it is disingenuous to pretend otherwise.

There is evidence of stone quarrying at the Rhosyfelin site?  So Bevins et al would have us believe -- but they might have had the good grace to acknowledge that their evidence has been hotly disputed since 2015.  And readers deserve to know that until now Bevins and his colleagues have refused to cite the peer-reviewed studies that draw concusions that are at odds with their own.  That in itself is enough to destroy their credibility as "experts".

The NB surface is rich in calcium carbonate deposits?  This suggests long burial either at stonehenge oft elsewhere.  On that we agree.  But I cannot for the life of me see how that reinforces the idea of human transport!  On the contrary, it provides strong support for everything i have said about the glacial transport and dumping of erratic materials from west to east.

It is claimed that if a glacier had carried the NB from West Wales to Salisbury Plain, or near it, it would have also left a scatter of similar stones across the region.   That is a fair point, but we still do not know how extensive the ice cover was, or what the glaciological conditions might have been.  There are erratics dotted about all over Salisbury Plain, as itemised by Thorpe et al in 1991, and it is worth reminding ourselves that only 50% of the stone settings part of Stonehenge has ever been excavated.   Therefore all statements by Ixer, Bevins and other about the frequency or type of rock fragments at the site will in due course have to be substantially revised.

BLUESTONE 32d -- new analysis shows it to be a foliated rhyolite like that of the NB?  This is a lie.  The stump that was revealed in old excavations was photographed, but not sampled.  So all we have is a speculation, based on a photograph.  This is slapdash and misleading science -- as we saw some months ago when a lump of rock bought in a rock shop in Whitby was used as a surrogate in a study of the Altar Stone.  In the eyes of many this seriously devalued the study and increased scepticism about its results.

Are  there  80 bluestones at Stonehenge?  This is often claimed.  But there are in fact only 43 monoliths and stumps, and in the view of the present author it is most likely that the planned stone monument was never completed.....

The image of a "typical collection of rock fragments" at Stonehenge.  This is worthless, since a collection and display of stone chips is exactly what it says it is.  It has no value as a piece of scientific information.  Other stone shapes are available at Stonehenge, but as far as I am aware, there has never been a controlled study of stone shapes in or beyond the stone settings.

Come to think of it, on the matter of stone shapes, has anybody ever looked at the full assemblage of Stonehenge monoliths and said "These stones were most certainly all quarried!". On the contrary, whenever I have asked geomorphologist colleagues about this, the response has always been "These stones are most certainly NOT quarried..........". That, of course, is, in my humble opinion, because they are all glacial erratics.

The Daily Mail article ends with a statement to the effect that "John's arguments have no basis in evidence.  To present it as fact, rather than hypothesis, is disingenuous."

That is all absurd.  I have never pretended that my conclusions are facts rather than opinions.  Talk about the pot calling the kettle black.......

Tim's Tiresome Triumphalist Tirades

 Here we go again.  Our old friend Tim Daw has taken to the media again to gleefully announce to the world -- or to his small part of it -- that the bluestone glacial transport hypothesis is dead.  His somewhat misplaced confidence is all based on the new article by the "gang of eleven" about the Newall Boulder, which I will deal with in due course.  Tim clearly thinks the article is the last word on the matter of glacial transport, demonstrating that he knows remarkably little about either the literature or the science.  He's clearly the stooge here -- but I wonder who put him up to it?

He has made some rather excitable pronouncements on Twitter (now X) which I can't get at since Mr Musk has decided that I am not a bona fide follower or disciple.  Something about the new paper "refuting any glacial transport"...........

Then on his blog he maintains his attack, using rather intemperate language.  Most of his posts pass me by, but I do read some of them. But he never, as far as I can see, allows dissent or discussion on his blog, and that point alone says everything we need to know.  It's all froth.....

His latest stunt involves an unattributed opinion on my recent post about the modelling of the British and Irish Ice sheet.  He puts the "opinion" in quotes, to show that the words are not his, but there is no way that the words are going to be taken seriously by me or anybody else, since they come from somebody hiding behind a cloak of anonymity. 

More serious is Tim's use of Researchgate in an attempt to give his outpourings a degree of "scientific respectability".  I have already pointed out his very dodgy use of AI on Researchgate as a substitude for individual academic scrutiny -- I am surprised that the moderators have allowed him to get away with it.  His latest piece, for which he claims authorship, has the grandiose title :  "The Demise of the Glacial Transport Theory for Stonehenge's Magaliths."  It's a short opinion piece, perhaps better defined as a personal attack, and I will of course respond to it when the tools of the trade are more readily to hand. (I'm on holiday in Sweden at the moment, dealing with the peculiarities of an iPad.......)

Washed surfaces and ice-transported boulders

 

 

Shoreline nwith a heavy concentration of erratic boulders on the coast of Granöören, near the eastern tip of Blidö, Stockholm Archipelago.  The coastline here is cut into a thick deposit of till, and the fines have been washed out by wave action.  When a "stillstand" occurs, with a rough equivalence of eustatic sea level rise and isostatic recovery rate, the concentration of boulders on the shoreline may be more pronounced.

I am intrigued that the geologists and geomorphologists who are "embedded" in the Stonehenge establishment still apparently believe that the big boulders dotted around the coasts of the Bristol Channel were transported by  floating sea ice and icebergs rather than by glacier ice.  This flies in the face of everything we know about glacial processes and about the Pleistocene history of the region, since nobody has yet demonstrated that the relative  positions of global sea level and the Bristol Channel coasts were close to those of today at a time when debris-laden icebergs could have been grounded between the tide marks.  On the contrary, on those occasions when ice-rafted debris might have been moved about in the channel, relative sea level must have been far below that of the present day, and the coastline must have been many miles away from its present position.   To argue that isostatic depression of the landmass caused the coastline to sink by an amount precisely equivalent to the eustatic sea level fall involves special pleading -- and there is no evidence to support it.

I am genuinely at a loss to understand what is to be gained by the continued promotion of the lRD (ice rafted debris) hypothesis, unless you want to fly in the face of the evidence and pretend (for rather obvious reasons) that the coasts of Devon and Cornwall were never glaciated.........

I am reminded of this rather silly argument every time I paddle the kayak around the coasts of the Stockholm Archipelago, which were once submerged beneath 100m or more of sea water.  The boulder-lined shorelines that we see everywhere are all the products of wave sapping of rock surfaces and exposed glacial sediments.  Wave action across a relatively narrow vertical range of a metre or two (there are no tides in the Baltic) removes all the finer materials -- clay, silt, sand and gravel -- and leaves behind the cobbles and the boulders.   If you tried to suggest to any Swedish geomorphologist that ice- rafting had anything at all to do with the presence of these big boulders, you would be laughed out of court.

So can we just have a bit of common sense here?

Was there a Bristol Channel Ice Stream?

 

The revised model from Ely et al.  The white areas show thin ice and sluggish or non-existent ice movement. The purple areas show ice streams or zones of relatively rapid ice flow.  Note the big Irish Sea ice stream and the much smaller but associated Bristol Channel ice stream heading east and pushing onto the Somerset Levels.

Thanks to Bevins et al (2025) for pointing me towards this article:

J.C. Ely, C.D. Clark, S.L. Bradley, L. Gregoire, N. Gandy, E.Gasson, R.L.J. Veness, R. Archer
Early View. Behavioural tendencies of the last British-Irish Ice Sheet revealed by data-model comparison
Journal of Quaternary Science. (2024)

It's a comprehensive and very specialised study of the hundreds of computer models of the behaviour of the British and Irish Ice Sheet (which also goes by several other names)  -- most of them relating the the Devensian glaciation.  They range from maximal to minimalist models and from extreme ones to ultra cautious ones.  Many of the older models can be rejected because the parameters used in their creation are now inadequate -- but the work of the BRITICE project has stimulated a new generation of models with much greater and more careful ground truthing used to check on their viability and accuracy.

Anyway, in tying everything up at the end of an extensive analysis, the authors produced a map for the southern part of the Ice Sheet which showed that (a) the ice sheet must have crossed the coastal barrier of Devon and Cornwall and impinged upon the small local ice caps of ther SW Peninsula (Dartmoor and Exmoor in particular) and (b) that there might well have been an eastwards flowing ice stream in the Bristol Channel.

I must admit that the latter suggestion (it is no more than that) came as a surprise to me, since previoius models have almost always suggested that the Bristol Channel was largely ice free at the times of extensive glaciation.  Partly, as I have pointed out many times on this blog, this defect arose from the assumption of an ice-free enclave in South Pembrokeshire, which makes no sense from a glaciological perspective.  So now we have a modern and apparently reliable model that agrees substantially with the situation portrayed in these mapped reconstructions:

After Kellaway, Williams-Thorpe and others

After Gilbertson and Hawkins

My own suggestion

Note that the latest modelled reconstruction shows ice pressing across the whole of Cornwall, and that the model does not show the greatest extent of Devensian ice in the Celtic  Sea.  Here the modelled outer edge of the Celtic Sea piedmont glacier is shown around the position of the Isles  of Scilly.  But as Scourse and others have pointed out, the extreme position was much further to the south, at the shelf edge.  At that time the ice must have been thicker and more extensive in the Bristol Channel, with accelerated streaming and a progression well inland of the Somerset coast.

Gradually, it all comes together............

The Stonehenge Lynch Mob marches out............

 

Well, this is fun.  The Stonehenge Lynch Mob has assembled all its forces and has marched out in the light of the midsummer moon, determined to string me up from the nearest trilithon.........

Their latest paper, a long and rambling (and in places repetitive) attack published in the Journal of Artchaeological Sciences, has no less than 11 authors, including MPP, Mike Pitts, geologists Bevins and Ixer, geomorphologist Jim Scourse, and archaeologist David Field.  Our old friend Tim Daw is in there as well.  

We have been waiting for this paper for some time, since it was prematurely cited by MPP et al towards the end of last year.   It was clearly rejected by the Journal of Quaternary Science in January 2025,  and later accepted (with revisions) by the Journal of Archaeological Science.  Make of that what you will.........

https://brian-mountainman.blogspot.com/2025/02/myths-fantasies-and-now-phantom-articles.html

There is a wonderful irony in the fact that the defenders of the establishment narrative have here written a long and detailed paper designed to destroy the "glacial transport hypothesis" and the credibility of my 2024 paper, having for the greater part of a decade refused to cite any of my publications or acknowledge that their bluestone narrative is disputed by anybody.  Indeed, I have complained on many occasions of their academic malpractice in this regard.  Suddenly, I find myself cited, not just once or twice, but in paragraph after paragraph of this new paper, with multiple quotations added in italics!  So I am very flattered.......

Who would have thought that a little boulder found in a cardboard box could have attracted so much attention?  Newall would have been delighted.

Don't you just love the title of the article?  ".... correcting the record."  The authors clearly think that they have replaced something dodgy with something authoritative and utterly reliable.  Hmmm.  Their arrogance knows no bounds.  Maybe I should now write something called "The Stonehenge Bluestones:  the truth" ??  What they have actually done, in this new paper, is to present a string of assertions and speculations as facts, as I shall demonstrate when I publish my detailed scrutiny.  Their over-interpretation of questionable evidence is par for the course; they do it all the time.

Watch  this space..........

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Richard E. Bevins, Nick J.G. Pearce, Rob A. Ixer, James Scourse, Tim Daw, Mike Parker Pearson, Mike Pitts, David Field, Duncan Pirrie, Ian Saunders, Matthew Power, The enigmatic ‘Newall boulder’ excavated at Stonehenge in 1924: New data and correcting the record, 

Journal of Archaeological Science: Reports, Volume 66, 2025, 105303, 

ISSN 2352-409X, 

https://doi.org/10.1016/j.jasrep.2025.105303.

Plumstone Rock

Somehow or other, Plumstone rock has escaped our attention.  It is a prominent rhyolite tor located on the ridge of Ordovician volcanic  rocks that runs between Roch Castle in the west (near Newgale)  and Trefgarn Gorge in the east.  The most prominent crags on the ridge are Poll Carn (Lion Rock) and nearby Maiden Castke (called by the locals the "family of lions" for obvious reasons).   

The rocks are for the most part flinty bluish rholotes, with considerable internal variation, including welded tuffs and agglomerates.  In certain light conditions the rocks appear to be pinkish or orange in colour.  The age of these rocks was disputed for many years, having been originally labelled as Precambrian -- but they now seem to be accepted as Ordovician.

The rock is hugely impressive and intimidating -- but  it is easily accessible from the Haverfordwest - Hayscastle road, and there is an easy short walk to the tor from the car parking area on the common.

It does not have the fragility of  Maiden Castle, and while the bulk of the tor is solid bedrock, on its flanks there are numerous massive detached blocks.  It is -- naturally enough -- a facvourite place for "bouldering".  I have not seen any striated surfaces on the tor, but there are some forms that are suggestive of ice moulding.  The big question is this -- what do the four tors on this ridge tell us about the history of glaciation across Pembrokeshire?

Newgrange: too much mythology and not enough facts

In this rather interesting article there is a timely assessment of some of the mythology surrounding Newgrange -- probably the most iconic prehistoric site in Ireland. The authors point out that many of the assumptions about Newgrange being a "special" place built by a powerful ruling clan as a tribute or homage to a "king" or powerful ruler are based on very little evidence -- or no evidence at all. They suggest that Newgrange was built over a very long period in many different phases, and that those buried there were not necessarily related, or people of high status within a ruling elite. They prefer a simpler story, devoid of heavy symbolism and romanticism -- indeed, somehat utilitarian and somewhat boring.

There are lessons here for all of us -- especially those who have developed the fanciful West Wales narrative of sacred and special places, magical stones, heroic quarrying activities and even more heroic long-distance stone haulage expeditions........

The post-processual obsession with fanciful narratives has a lot to answer for.

It might just be a good idea for the archaeologists working in West Wales to go back to basics and work out just what evidence there is on the ground, as suggested by quite a few of us from other disciplines over the years.




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




Smyth J, Carlin N, Hofmann D, et al. The ‘king’ of Newgrange? A critical analysis of a Neolithic petrous fragment from the passage tomb chamber. Antiquity. 2025;99(405):672-688. doi:10.15184/aqy.2025.63

ABSTRACT

Recent genomic analysis of a skull fragment from Newgrange, Ireland, revealed a rare case of incest. Together with a wider network of distantly related passage tomb interments, this has bolstered claims of a social elite in later Neolithic Ireland. Here, the authors evaluate this social evolutionary interpretation, drawing on insecurities in context and the relative rarity of engendered status or resource restrictions in the archaeological record of prehistoric Ireland to argue that the status of individuals during this period is better understood through unstable identity negotiations. Inclusion in a passage tomb, while ‘special’, need not equate to a perpetual elite.

Carn Fran summit

 

Many years ago (about 63, to be more precise) Francis Synge pointed out to me that the rhyolite hills between Fishguard and Dinas were rather interesting.  He pointed out how smooth and rounded they were, in contrast to the craggy uplant tors found at higher altitudes on Mynydd Dinas, Carningli and Mynydd Preseli.  The main summits are Carn Fran and Carn Gelli, and there are half a dozen minor summits as well.  They are all "clean" and relatively smooth, and a number of geomorphologists in the past have suggested that they were glaciated quite recently while the other higher summits were above the upper glaciation limit.  

Nowadays it is accepted that that interpretation is rather simplistic, and that changes of landscape characteristics may be related to changes in glacier bed conditions.  Thin ice on rounded upland terrain may have been frozen to its bed -- ant therefore incapable of intensive erosion -- while thicker ice in the lowlands may have been above the pressure melting point, flowing faster and with greater erosive capacity........

In the past I have never managed to get up onto the summits of these hills because of thick vegetation -- gorse, brambles, heather and bracken.  But in recent years a "permissive path" has been opened, and this gives easy access to Carn Fran.  We have been doing some work up there -- more of which in due course......

 

The Foel Drygarn quarries

 

I have done a number of posts on the Bronze Age and Iron Age quarries near the summit of Foel Drygarn.  I was up there a couple of weeks ago, and this is one of them.

  I am quite convinced that the quarrymen were quite disinterested in large blocks of stone, and targetted rubble and small stones that could be used in the 3 spectacular burial mounds on the summit and in the defensive embankments around the settlement site.  In most cases all they had to do was to take loose stones from banks of scree -- but in some cases they have clearly taken loose stones from the degraded flanks of the rhyolite and micro gabbro tors.

Nothing much was needed in the way of technology, although I would guess that wooden levers might have been used in order to extract the stones from the ground.

A Foeldrygarn puzzle

This is a photo of one of the microgabbro outcrops near the summit of Foeldrygarn.  The outcrop is a small one, surrounded by grassy banks.  It's a degraded small tor, but here the focus of interest is the semi-circular arrangement of stones set in the turf.  This is quite unlike anything I have seen elsewhere in Preseli.  There are plenty of semi-circular stone banks set against small cliffs in the uplands of Preseli, but these are characteristically composed of curving lines of boulders or low ridges up to 2 m wide.  Some appear to have been low walls that maybe supported roof timbers -- with the upper ends of the timbers supported against the rock face.

Here on Foeldrygarn we see a "band" of large boulders or slabs, many of which seem to have been placed end to end...........

The site lies within the summit hillfort and not far from the triple Bronze Age burial mounds -- all made with locally quarried stones which were carried short distances uphill.  The stones were all small enough to carried by one man -- or sometimes two men working together.  Large boulders and slabs were rejected on the grounds that they were unmanageable -- and maybe this holds the clue to what was going on.  Maybe the "band" of large stones was made entirely of rejected stones, pushed aside while the smaller stones and finer debris fragments were carried away for the construction of bural mounds and later for the fortified mounds that are prominent features of the site?

Has anybody seen anything like this elsewhere?  Any other theories about what was going on here?

Carnalw

 Another of Hugh Thomas's wonderful Preseli images -- this one shows Carnalw, near the eastern end of Mynydd Preseli.

The Blatten Glacier Disaster

Before.........

.... and after

There is a fascinating piece of reportage (with spectacular animation) on the BBC web site, relating to the recent disaster in the Swiss Alps.

https://www.bbc.co.uk/news/resources/idt-c7f929de-96a9-45e5-b1bb-31de82fce72d

Thank goodness there was no loss of life, since the idyllic village had already been evacuated, prior to the catastrophic event.  I thought, before I looked into this, that the "glacier collapse" took place in the upper part of a regenerated glacier, like that of Supphellebreen at Fjaerland in Norway -- but no, this was a very small and very dynamic independent glacier (Birch Glacier) in a high mountain environment.  High rates of snow accumulation, steep slopes, and rapid ice flow under the influence of gravity, on slopes dominated by frost shattering and rockfalls. Permafrost melting and rainfall in the Alps (as distinct from snowfall) were contributary factors in causing additional debris mobility.   

The old photos show a substantial fan of debris close to the village, with no clear terminal or other moraines.

There is no doubt at all that collapses like this will now occur with increasing regularity in all of the high mountain environments where there are thousands of vulnerable glaciers of this type.......

(For very good enlargements of the images, just click on them.)

The other evening.......

 Thanks to Lynne for this photo taken at the beginning of my talk the other evening at Canolfan Bethlehem, Newport.  There was an excellent response from the audience, which included many who have also heard MPP reporting on his "discoveries" during and after his September digs in North Pembs.

Just in -- the following comment:  ".........really enjoyed your talk last week. It was so engaging that I don't think anyone minded the hard pews! We thought the talk was a nicely balanced assessment of the pros and cons of all 'the available theories' about how the Bluestones were transported. You have, as one of my bosses used to say, 'relentless pounding logic' on your side. Very well done.

An Irish erratic near Cardigan?

 

I found this small erratic of Carboniferous Limestone in the Irish Sea till at Gwbert, near Cardigan, today.  It has two beautiful brachiopod fossils in it, and as befits a far-travelled stone its surface is covered in striations.  

Where has it come from?  The best bet is that it has come from somewhere in central Ireland, and limestones rich in braciopods seem to be especially common in the Burren area on the west coast.  Here is an example:

However, from what we know of past iceflow directions, a source somewhere near Dublin seems more likely:

Geological map opf Ireland -- the light blue tint shows the area of Carboniferous Limestone outcrops.

If the erratic really did come from Ireland, there must have been much more mixing of ice streams and erratic material in the Cardigan Bay -- St Georges Channel area than has been previously recognized............

We also have to consider Anglesey and the  North Wales coast as source areas, although the outcrops there are of very limited extent.  This is from the GeoMon Global Geopark web site:

.............highly fossiliferous limestones outcrop all long the east coast southwards from Lligwy to Penmon [and along the coast of North Wales from the Great Orme to Prestatyn]. These rocks were laid down in cycles as the sea transgressed and retreated as many as 11 times over North Wales. On Anglesey, only four of these cycles, which consist of limestone followed by sandy beds and then mudstone were deposited. The rocks are rich in brachiopods and corals and often exhibit palaeokarstic surfaces and rarer sandstone pipes.

An Anglesey origin for the erratic is, on balance, most likely since this accords most closely with the ice flow pattern shown on the map above.

An interesting dilemma.........

Gwbert raised beach platform

 

Down on the Teifi Estuary this morning checking out the situation on the east side of the river mouth. There used to be amazing exposures of Irish Sea till here (back in the 1960's) but they were destroyed with the building of new coastal defences and a new caravan park.  

The Irish Sea till is still there, in patches, resting on the old raised beach platforms which are still visible.  These are the counterparts of the raised beach platforms exposed at Poppit, on the other side of the river mouth.  There are occasional exposures of till, fluvio-glacial materials and slope breccia, but because there has been so much slumping it's almost impossible to see stratigraphic relationships. 

The higher parts of the raised beach platform seem to be well above the influence of current HWM coastal processes, so  I interpret the smoothing and rounding of bedrock undulations to glacial erosion prior to the deposition of the till.

The glaciated summit of Carn Llidi

 

 

Thanks to Hugh Thomas for posting this great pic, taken on the summit of Carn Llidi nearSt Davids.  Ice-smoothed summit mounds.  In the distance is Ramsey Island, also with glaciated summits -- the source of a great range of glacial erratics found in mid and south Pembrokeshire.

The latest on the bluestones..........

 

Tonight, 7 pm, at Canolfan Bethlehem, Newport.....

Erratic dispersal modelling -- the Irish Sea Ice Stream

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. BradleyVersion of Record online: 15 May 2025

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

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

ABSTRACT: Glacial erratics are geologically distinctive rocks transported away from their source area by ice sheets and deposited in lithologically different bedrock areas. They have attracted much scientific curiosity with >24 000 observations across the British Isles. A common misinterpretation is that they took a nearly direct line of transport from source to resting position, neglecting to change ice flow directions during ice sheet growth and decay. To rectify this, we sequentially modelled erratic time‐space trajectories at 1000‐year timesteps using ice flowlines in an empirically constrained ice sheet model simulation to predict erratic deposition areas. We addressed the processes of entrainment and deposition by combining all potential trajectories into a single footprint of possible locations. Erratic dispersal is predicted for three geologically distinctive lithologies; Shap Granite of Northern England, Galway Granite of Ireland and the Glen Fyne igneous complex from Scotland. The footprint of predicted trajectories compared against 1883 observations of erratic locations was found to successfully explain 77% of the observed erratics. Most erratics were explained by flow directions during ice retreat; however, some required earlier ice divide shifts to produce potentially long‐duration, multiphase pathways. Our analysis demonstrates the possibility of explaining many erratics without explicitly modelling the complex processes of entrainment and deposition.

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

This is an interesting paper in which the authors test a modelling exercise agtainst "ground truthing" for the distribution of erratics from three different bedrock sources -- one in Ireland, one in northern England, and one in western Scotland.   Figure 4 (at the head of this post) shows the latest version of the streamlines of the Irish Sea Ice Stream as far south as the Bristol Channel, predicting where distinctive erratics from the Loch Fyne igneous complex might be found.

See this post:

https://brian-mountainman.blogspot.com/2024/08/possible-altar-stone-sources.html

and this:

https://brian-mountainman.blogspot.com/2024/08/in-praise-of-ailsa-craig.html

This new work has a bearing on the Altar Stone debate -- including the possibility that it might have come from one of the ORS sandstone outcrops in the Midland Valley of Scotland or the Southern Uplands.   We already know a lot about the distribution of Ailsa Craig erratics -- this new work suggests that other erratics from much further north -- around Loch Fyne -- might also have found their way into the Bristol Channel and onto the coasts of SW England.

I must admit to being very intrigued by the postulated streamlines for South Pembrokeshire and the Bristol Channel and by the positions of the arrow tips.  There is no ground truthing to show that there ever was a significant ice edge position where it is shown on Figure 4.  And of course it is wildly improbable that erratic-carrying ice ever did swing round in Carmarthen Bay and move north-westwards onto the coast of SE Pembrokeshire -- ie directlly opposite to the direction of ice flow across the rest of the county.   The model that created the map clearly needs some tweaking........