Some of the ideas discussed in this blog are published in my new book called "The Stonehenge Bluestones" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
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Thursday 31 August 2023

The inexorable perpetration of unreliable research

Here we go again --  deja vu for the umpteenth time.  Yet another article extolling the virtues of Waun Mawn as the place where Proto-Stonehenge was located.  The usual simplistic version of the narrative, designed here for tourists and interested lay people........ and to hell with the truth.

This is, of course, more for entertainment than education, but nonetheless it teaches us what happens when researchers irresponsibly publish research which is half-baked or simply downright defective, promoting a narrative designed to be appealing and exciting, involving huge assumptions and speculations that have little or no relation with the real world.  Of course many of the points made in this careless Travel Newsletter were dismissed by people like myself from day one, before being dismissed belatedly by MPP's team members themselves.  They have been forced to accept (from their own work)  that the famous pentagonal stone socket had nothing to do with any Stonehenge monolith, that the stones at Waun Mawn had nothing to do with any stone quarries, and that there is nothing in the evidence suite that connects Stonehenge and Waun Mawn.  There never was a complete -- or even partial -- stone circle here.  And there are no demonstrable astronomical alignments that make any sense.

The author of this piece was clearly aware that Tim Darvill had questioned the reliability of the Waun Mawn narrative last year -- but nonetheless the temptation to spread a thrilling narrative was too much for the writer and the editor.  So they went ahead and published it, with a nonsense headline designed for maximum impact.

Yet again, the members of the public are misled by a false narrative flagged up as "scientific research".  It's all rather sad......


Interested In Stonehenge? See Where It Once Stood In Wales Before It Was Taken To England.
Aaron Spray
The Travel -- Newsletter
29 August 2023

Wednesday 16 August 2023

The Newall Boulder: the human transport hypothesis is as dodgy as ever

The bullet-shaped Newall Boulder now held in Salisbury Museum.  The faces have varying degrees of "freshness".  At the top of this photo we can see the damage done by geological sampling.

I should, of course, have been asked to review this paper prior to publication, but nowadays researchers effectively get to choose their own reviewers and to ban those who are deemed likely to be unfriendly........  Anyway, here is the peer review I would have written, if I had been asked.

Declaration of interest:  I have personally examined the "Newall Boulder" in Salisbury Museum, and have already expressed reservations about a previous report co-authored by Ixer, Bevins and Pearce (see note at the end of this review). 

Peer review

Richard Bevins, Rob Ixer, Nick Pearce, James Scourse, Tim Daw. 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 2023: 1-15

This paper seeks to demonstrate that a small sub-angular boulder found in a Stonehenge excavation was knocked off the tip of a rhyolite monolith that no longer exists, having earlier been excavated from a known site in West Wales prior to human transport to Stonehenge for use in a bluestone setting.  The claim that natural processes were not at any stage involved in the entrainment, transport and emplacement of the boulder is an extraordinary one, which can only be supported by extraordinary and powerful evidence.  Has that irresistible evidence now been provided?  In the view of this reviewer, the answer is "No".

At the beginning of the paper the authors suggest that there are eleven known "bluestone lithologies" which must have been associated with specific numbered orthostats.  The labelling of these lithological groups is confusing, to put it mildly, and the authors fail to acknowledge that each group probably  involves stones from several different provenances.  Further, during the excavations at Stonehenge at least 46 "exotic" rock types have been turned up in excavations, many of them having no links at all with any of the known "bluestone orthostats".  To ignore them is to defy logic. Angular fragments, abraded pebbles and cobbles found in the sediments, which may be crucial for the interpretation of what happened at Stonehenge, are simply dismissed by the authors. This fact alone undermines many of the claims made here about the human transport of the bluestones.  If the bluestones were selected for their "special" qualities or indeed quarried from sacred sites, do the authors really believe that monoliths and smaller stones were extracted deliberately from 46 different places?

In their literature review relating the the glacial transport / human transport controversy, the authors should have made reference to the modern work relating to very extensive glaciation by the Irish Sea Glacier, and the modelling work suggesting that the glacial transport of the Stonehenge bluestones was "not impossible" (Hubbard et al, 2009).

In their examination of the 18 "Newall stones" from the Hawley excavations at Stonehenge, the authors make somewhat heavy weather of the suggestions that some, at least, might have come from North Wales.  My understanding is that the suggestions of North Wales / Lake District origins for the small boulder referred to as RSN18, by Harrison and other BGS geologists, were very tentative.  But they were all quite convinced that the boulder (referred to as a strongly welded acid vitric tuff or ignimbrite) was different, geologically, from any of the known rhyolites (at that time) from Mynydd Preseli.  I agree with that. The Newall Boulder rock is darker in colour, rougher and more "flinty" than the rhyolite of Rhosyfelin. 

The authors' investigations of the petrography of the thin sections from the Newall Boulder are interesting but inconclusive.  The authors claim that "petrographically the RS18 fragment matches rhyolitic tuff from Craig Rhos-y-felin", in turn claimed as the "dominant source of the Stonehenge rhyolitic debitage" and as the site of a Neolithic bluestone quarry.  This is not supported by the evidence presented.  The photomicrographs comparing the texture and lithology of RS18 and Craig Rhos-y-felin rhyolite show similarities, but not perfect matches, and there remains a strong possibility that RS18 has come from elsewhere on an extensive rhyolite outcrop, or even from another outcrop entirely unrelated to Craig Rhos-y-felin. Attempts by the authors to demonstrate that the foliations in the Newall boulder and on the rock face at Rhos-y-felin indicate that the one was derived from the other are unconvincing, since we are not told how many other outcrops of foliated rhyolite there may be in West Wales. The whitish weathering crust, also cited as an indicator of a Rhos-y-felin origin, is also unconvincing, since whitish weathering crusts are present on many other West Wales rhyolite outcrops.

The reported pXRF work on the Newall boulder, also reported in section 2 of the paper, is similarly inconclusive. The bivariate plots shown in Figure 6 were -- as is normal in papers of this type -- created specifically in order to demonstrate affinities,  but this does not mean that the demonstrated relationships are unique or significant.  The overlaps between the fields for the Newall samples and the Rhos-y-felin samples may be no more marked, for example, that the relationships between the Newall samples and the plots for Carn Alw,  Ty Canol Wood, or Maiden Castle, which the authors may have, but have chosen not to show us.

Slickenside features on one face of the boulder, which must coincide with a fault plane.  

On page 9 the authors accuse Kellaway of mistakenly interpreting slickenside lineations as glacial striations.  Kellaway was a good geologist, and I do not believe he could have made such a stupid mistake.  The striations which he interpreted as having a glacial origin are much more subtle and discontinuous, and can be seen only during a minute examination of the boulder surface. This matter is discussed again on page 10, where there is a serious misrepresentation of the characteristics of glacial striae.  Striae are NOT typically continuous over a large proportion of a facet surface.  The clast shown in Figure 9 may be an ideal text-book illustration, but the great majority of striated clasts which I have encountered during a lifetime of working with glacial sediments are not like this at all; many of them show just one or two surface scratches, which may or may not be sub-parallel or cross-cutting.  The Newall Boulder, which I have examined, has a few very subtle scratches that may be striae, and they are quite distinct from the slickenside features shown in Figure 10.

It is disingenuous of the authors to pretend that because slickenside features are present on the Newall Boulder and at Craig Rhos-y-felin, this demonstrates a source for the boulder.  Slickenside features including slickencrysts are common across West Wales, in all faulted lithologies and of all ages.

On page 12 the authors refer to the "consistency of lithologies" in the Newall bluestone assemblage as an indication of "human selection of the material" rather than "a random process of entrainment in glacial till".   The entrainment of debris in glacial deposits is not a random process.  The authors do not explain why or how human beings should have selected around 46 different lithologies (mostly from the west)  for incorporation into Stonehenge sediments.  Were they disinterested in lithologies from the north, east and south?   They claim that "several of the bluestone lithologies have been sourced to specific outcrops in North Pembrokeshire, namely Craig Rhos-y-felin, Carn Goedog, Cerrigmarchogion and Carn Ddu Fach."  That is a misleading statement; these sources have been suggested, but never adequately proved, and indeed in the papers referenced the authors themselves accept that there are NO definitive sources that are beyond dispute.  The fact that many of the bluestones come from a limited geographical area is NOT suggestive of the human selection of the bluestones; on the contrary, since so many different rock types are represented in the Stonehenge assemblage of bluestone clasts, the supposition must be that glacial transport was responsible for stone transport on a substantial scale.  It is vanishingly unlikely that small fragments and cobbles in the debitage (many of them quite unrelated to bluestone orthostats) were selected and then carried to Stonehenge by human beings.

The authors argue on p 11 that the "snub nose" shape of the Newall Boulder is typical of outcrops at Craig Rhos-y-felin.  I know the site, and I do not accept that. They also suggest that the boulder is probably the broken tip of a destroyed orthostat (maybe stone 32d) at Stonehenge.  On the contrary, the boulder's "bullet shape" is suggestive of glacial transport, with abraded edges and discernible facets.   They also suggest that the "fresh" surface of the boulder shows where it was broken from the complete orthostat.  However, the fresh surface of the boulder is of very limited extent, and does not coincide with a sizeable cross-cutting fracture scar.  Examination of the boulder shows that Kellaway was most likely correct in assuming that part of the exposure of dark blue "fresh rock" was the result of limited damage (probably man-made) inflicted on a boulder only slightly larger and heavier than the one we see today.  Also, it borders on the absurd to suggest that a flimsy and fractured rhyolite orthostat with dimensions no greater than 2m x 40 cm x 30 cm would have been quarried from Rhosyfelin, transported to Stonehenge, and incorporated into a bluestone setting without falling apart in the process.  Indeed, the unsuitability of Rhosyfelin rhyolite for use as standing stones has now been accepted by Bevins, Ixer and other authors who some years ago flagged up the site as "the Pompeii of Neolithic quarries."  The evidence against quarrying at this site was presented in detail in two peer-reviewed papers by John, Elis-Gruffydd and Downes which have been completely ignored by the authors of the present paper.

Finally, on the matter of glaciation and glacial erratic transport, the authors summarise the evidence relating to erratic trains and glacier extent in the Bristol Channel arena which has been presented by selected researchers.  They ignore the work of other researchers, and in doing so they fail to address the glaciological conundrum of how the ice of the Irish Sea Ice Stream can have reached the shelf edge in the Celtic Sea without also overwhelming the inner reaches of the Bristol Channel and the Somerset Lowlands.  They also fail to mention the modelling work which has shown that glacier extent at the time of the Greatest British Glaciation might well have involved an ice edge on or near Salisbury Plain.  They fail to mention the presence of very old glacial sediments in the Somerset Levels, near Bath and on the coasts of Devon and Cornwall, and the presence of high-level erratics on the coasts of the South-west of England which cannot be explained other than by an extensive glaciation. They claim (falsely) that there are no "bluestone erratics" in the vicinity of Stonehenge, while ignoring the fact that most of the Stonehenge bluestones are not beautiful pillars as portrayed in the textbooks but classic glacial erratics (boulders and slabs) with distinguishable facets, abraded edges and thick weathering crusts.  The evidence of Stonehenge glaciation is staring the authors in the face, without apparently being noticed.

The authors claim that Clark et al (2022) and Gibbard et al (2022) summarise the most recent evidence of Devensian and earlier ice limits in Britain, and that there have been no significant changes in proposed ice edge positions.  But those two authors would be the first to admit that there are large inconsistencies in parts of the evidence base, and some of the "accepted" ice limits in parts of the Bristol Channel /Celtic Sea arena do not actually make much sense.......... 
It is clear that we are still some way from the telling of the full story.

An attempt by Gibbard and Clark to represent the ice edges for three glacial episodes.  In places these lines are matched by good "ground truthing", and in places they are highly speculative.  The Wolstonian ice edge shown for mid-Wales makes no sense at all....... 

However strong the evidence of glaciation and glacial transport may or may not be, it is far stronger than the evidence for human bluestone transport.  No evidence for human bluestone haulage from West Wales to Stonehenge has ever been found by the present authors or by anybody else, and the authors should have the good grace to admit this.  Indeed, there is no good evidence for substantial stone haulage with respect to any of the great megalithic monuments of the British Isles.

The contention that the Newall Boulder is not a glacially transported clast is unsupported by the evidence presented in this paper, as is the contention that it is a knock-off from a mysterious unknown Rhosyfelin rhyolite orthostat.  

Without considerable revision, this paper is not of sufficient quality for  publication in a serious scientific journal.


Declaration of interest: the following items are relevant:

Monday 14 August 2023 -- a repository for all the best fairy tales

Erratic resting on a bergy bit in a vast glacier meltwater lagoon in Iceland.  Nothing to do with the sea or the coast, but deemed by TD to have something to do with coastal boulder emplacement........

I don't usually waste valuable space on this blog to considering the contents of other blogs --  but our friend Tim Daw, over on, has just demonstrated that when it comes to matters glacial he really is out with the fairies.

In a post entitled "erratic castaway" he argues that "any Glacial erratic found on the edge of a body of water is probably a boulder that hitched a ride on an iceberg rather than evidence of actual glaciers."  He has done a nice little image search on Google and has come up with a couple of pictures of glacial erratic boulders resting on bits of floating glacier ice -- and he assumes that these photos prove his hypothesis. 

Oh dear -- how best to put this in the kindest possible way?  Tim has clearly never heard of eustatic and isostatic sea-level effects, and is clearly blissfully unaware that at a time when ice rafting of the type he now demonstrates was occurring around the British Isles, relative sea level was more than 100m lower than it is today, and the coastline of the Bristol Channel coasts was more than 100 km to the west.  The whole of the Celtic Sea arena was dry land.  During the Quaternary interglacials, when sea-level was more or less where it is today, with the coast in more or less its present position, there is no way that the ice rafting of large erratic boulders can have occurred in southern Britain.

This blog has a very good search facility, and there are abundant articles on glacial isostasy and palaeo-coastal positions.  I recommend to Tim that he does a little research.......

Tim should stick to what he knows.  As I have said before to those who purport to be bluestone experts, with friends like him, who needs enemies?

The Limeslade erratic boulder -- probably not from Mynydd Preseli

Thanks are due to Dr Katie Preece and Prof Peter Kokelaar for their initial professional assessments of the Limeslade erratic boulder. Thanks are now also due to to Prof Tim Darvill and his colleague Dr Steve Parry, who offered their services back in the spring of 2022 when the Limeslade boulder was discovered by Phil Holden.  We now have the pXRF and thin section analyses from the two samples collected by Phil.  Better late than never -- and one should never turn down kind offers of assistance, especially if one has no access to academic research funding.

According to Prof Kokelaar, cited by Rob Ixer on the Megalithic portal discussion forum, the Limeslade "giant erratic" is "......... a metamorphosed coarse dolerite (not quite gabbro), sparsely porphyritic with oscillatory-zoned euhedral and subhedral plagioclase phenocrysts mostly ~0.5 cm and up to 1 cm; dark patches could be (altered) ophitic pyroxenes. The rock shows sub-parallel feldspathic banding roughly perpendicular to the long axis (2.2m) of the boulder. ...... I suggest that from my limited experience the boulder is an erratic and would be consistent with derivation from the Lower Palaeozoic of north Pembs. The banding perpendicular to the ‘columnar’ length is fairly typical of some coarsely jointed sills I have mapped between Fishguard and St David’s Head.  Ironically the only thing that can be said with certainty now, firmly established by the extraction scar, is that the erratic is NOT preselite from the Preseli Hills -- the most abundant rock type of the Stonehenge bluestones -- as there is not a spot on site or in sight, so it is not a spotted dolerite, hence eliminating it from the established source area for the Stonehenge orthostats and suggested quarries."

We will shortly publish the geochemistry (pXRF) results and the petrological analysis, but we can say now that the work confirms the initial visual assessments by Dr Katie Preece, Prof Peter Kokelaar and others who concluded that it is a greenish unspotted dolerite or microgabbro with crystals of feldspar and pyroxene similar in some respects  to some of the unspotted dolerites of North Pembrokeshire.  According to Dr Steve Parry the rock is best described as an ophitic microgabbro.  He states: “In terms of its state of alteration, the constituent feldspar is argillized and some of the pyroxene appears to be uralitized."  Whether these characteristics, together with the plots of trace elements, will provide an accurate provenance for the boulder remains to be seen.

Once the results are published, we will of course welcome further research and comments which might help to narrow down the range of possible sources for the erratic.

Weirdly, in the discussion blogs we have been accused by Rob Ixer and Tim Daw some sort of cover-up with regard to the analytical results, although they have never explained what advantage we might have obtained from keeping information out of the public domain. As far as I am concerned, I have no "preference" regarding the origin of the boulder.  I really do not care where it has come from, although it is self-evidently a glacial erratic carried from somewhere to the west or north-west.  I doubt that even Ixer and Daw would argue that it is a bluestone monolith destined for Stonehenge but dumped on the coast as a result of a pre-historic shipwreck..........

To conclude -- the new evidence supports the suggestion that the erratic has not come from Mynydd Preseli, and that it is most likely from one of the Ordovician sills or dykes in NW Pembrokeshire.  The source might be a prominent outcrop such as Penbiri -- or the rock might have been entrained by overriding ice from one of the less significant exposures in the landscape.  As suggested in earlier posts, the entrainment "event" might have occurred during the Late Devensian glaciation -- but it is more likely to have been during the Anglian glaciation around 450,000 years ago.

Whatever its erratic history may be, the boulder demonstrates that the Irish Sea Glacier impinged upon the Gower coast, carrying erratics from the west and displacing local Welsh ice on at least one occasion.  This confirms the conclusions drawn by Prof Peter Kokelaar in his 2021 book on Gower.

Sunday 13 August 2023

The curse of the Knowledgeable Native

Many years ago an old friend of mine, who is into mathematics, astronomical alignments and that sort of thing, went into print with an erudite piece about some rather nice Bronze Age standing stones on the upland of Mynydd Dinas.  They were apparently aligned with something or other, and the article was well received, causing many other erudite people to visit the site and record their own observations and calculations.

I went ambling past one day, and got talking to two local farmers who were leaning on a hedge and putting the world to rights.  We chatted about the standing stones (one used as a rather spectacular gatepost and the others in a roadside hedge) and they told me that all three had been embedded in the turf in one of the fields, causing such a nuisance that they were removed with the aid of a mechanical digger in 1977 and placed in their present positions.  They showed me the depressions or extraction pits from which the stones had come, and pointed out to me the chain marks and other surface damage on the stones caused by the process of extracting them and moving them.  They had nothing at all to do with the Bronze Age or with ley lines or astronomical alignments.............

The moral of this little tale?  Don't be too hasty in theorising or fantasising about archaeological features, since there may be some local person not far away who knows far more about your special site than you do..........

Actually the "knowledgeable native" is probably the curse of archaeologists -- especially those with a tendency to create elaborate narratives on the basis of very little evidence. 

This brings to mind some of my posts about the wisdom of Carl Sagan and his insistence that those of us who are reasonably qualified should "knowledgeably question" the claims that are made by researchers about their findings, and the reliability of the evidence brought forward in support of those claims.   If knowledgeable natives like me do not scrutinize and question the findings and speculations of Parker Pearson, Bevins, Ixer and their colleagues in Mynydd Preseli, who will?  Most people nowadays (including academics who should be ashamed of themselves) do not read journal articles critically and prefer to read abstracts and press releases instead -- which can, of course, lead to absolute nonsense being widely accepted as the truth.  We have seen it over and again in the bluestone research programme -- extravagant claims made about geological affinities, quarrying, bluestone transport, lost stone circles and so forth are all too often accepted and acclaimed by the academic community and by the media who simultaneously ignore the reservations of people like myself. 

Those who are responsible for the development of the fantastical bluestone narrative put the word out that I am an ignorant and irritating old fool, and then have to admit that (as I have said all along) there never was any bluestone quarrying on an industrial scale at Rhosyfelin and Carn Goedog, that bluestone fragments at Stonehenge have come from multiple sources, that spotted dolerite and foliated rhyolite monoliths have never been used preferentially in stone settings, that there never was a lost stone circle at Waun Mawn, that the stones used on the moor were locally collected, and that the "astonishing site" had nothing whatsoever to do with Stonehenge.

Funny old world.......

Monday 7 August 2023

Submerged forest, Manorbier.


Thanks to Adrian James for publishing these photos on the Pembs geology Facebook page.  They show good exposures of the peaty bed and some substantial tree trunks / branches, where the stream reaches the beach.