Some of the ideas discussed in this blog are published in my book called "The Bluestone Enigma" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
To order, click

Monday, 23 April 2018

Even more South Pembrokeshire Till

Over the course of three long walks on the South Pembrokeshire coast, I have been finding till all over the place.   At the risk of boring readers, here are some more exposures.  I want them to be recorded for posterity, because South Pembrokeshire is bound to become a focus of activity in the future, as people renew their efforts to define the West Wales Devensian ice edge.  Here we go:

Reddish till made up mostly of shattered limestone fragments with some rounded and faceted erratic pebbles, on the clifftop near Huntsman's Leap.

Rounded erratic cobble in fresh till near Mewsford Point

Till exposure on the clifftop near Bullslaughter Bay

Fine-grained till with mostly small erratic pebbles -- clifftop near Bullslaughter Bay

Till exposed on the clifftop on the western flank of Flimston Fort.  Here again the till is packed with pebbles of quartz -- from ancient Pliocene river gravels or beach deposits?

Another exposure of till near the western edge of Flimston Fort -- on the clifftop.

From an old post:

I have been digging around in some of the old records of the Geological Survey -- from about 1905-1938 -- and have found that the old geologists responsible for the fieldwork in west Wales (Strahan, Cantrill, Dixon, Thomas and Jones) knew all about the glacial deposits scattered across South Pembrokeshire. In their publications they describe many locations where thin till and glacial erratics are to be seen -- including Bullum's Bay on Caldey Island. So I'm not the first to describe this till, by any means. In 1905 EL Dixon wrote of Bullum's Bay: "..... the glacial deposit appears to overlie the raised beach, although the exposure is obscure, and the evidence of superposition is not so conclusive as in Gower." (Summary of Progress for 1905, Mem Geol Surv, p 70). He and his colleagues described glacial deposits at Landshipping, in the inner reaches of Milford Haven; till about 7 ft thick at St Florence; glacial sands and gravels at Bubbleton; gravel and sand at Norchard; sandy loam with erratics at Lamphey; and glacial deposits in many pipes and solution hollows at Catshole Quarry, Pembroke, Sandtop Bay on Caldey, and in other places where Carboniferous Limestone is found. Generally the till in such places is coloured red or pink -- with an obvious association with ORS rocks, and striated sandstone pebbles are also recorded in the deposits, as are pebbles and larger stones of greenstone and felsite.

The Geological Survey maps for the Tenby districts show patches of glacial deposits, as do the maps for the Pembroke and Carmarthen areas.

These are the Memoirs on the Geology of the S Wales Coalfield -- Part XI Haverfordwest - 1914; Part XII Milford - 1916; and Part XIII Pembroke and Tenby - 1921. All are out of print long since, but you will find them in libraries.

The only patch of diamicton or till shown on the latest geological map for  in this large coastal tract is just to the east of the eastern arm of the Bosherston Lily Ponds.

In the memoirs the tills or diamictons of South Pembrokeshire are generally referred to by the old geologists as belonging to the "older Drift" glaciation.   They may be right that many of the inland deposits are very weathered and very old -- but I am convinced that the coastal tills are fresh, and that they must be assumed to be of Late Devensian age.

At the moment, I see no reason to make any great alterations to this map:

Erratic boulders on South Pembrokeshire clifftops

Erratic boulder exposed in an inaccessible position on a vertical clifftop near the Huntsman's Leap, west of St Govan's Head.  This one is maybe a metre long -- heavily abraded and polished and bedded in a rough till made up mostly of broken limestone fragments.  The boulder looks to me ro be igneous, but maybe we will never know.  One day, before long, it will go crashing down to the beach below........

This heavily abraded boulder projects from quite a thick layer of reddish till -- again in an inaccessible position -- on the clifftop of Bullslaughter Bay, about 2 km east of the Green Bridge of Wales.  It looks to me as if it might be rhyolite........

Strange till near Stackpole Head

A couple of days ago, on this very beautiful stretch of coast, on the cliffs of Stackpole Warren, between Mowingward and Raming Hole, I encountered several exposures of rather interesting till.  It's something of a miracle that I am still here to tell the tale, because accessible clifftop exposures are few and far between on the top of these vertical limestone cliffs.  Taking samples is very difficult in most cases, and even getting photos requires rather a good head for heights.  It's a good job I don't suffer from vertigo......

Anyway, to the till.  Here are some pics:

All being well, you can click to enlarge each of the above.  The most striking characteristic is the presence of abundant quartz pebbles and cobbles.  Some of them are broken, but many are intact -- having survived glacial transport from not very far away.  But where did the pebbles come from?  At Flimston, a few kms to the west, there are some claypits in which the famous Flimston Oligocene clays are exposed. Organic remains confirm the age.  They are up to 15 m thick, and appear to have been laid down in lacustrine conditions;  that's interesting in itself, given that the bedrock is highly fractured Carboniferous Limestone.  But associated with the clays (probably above them) are deposits of beautifully rounded quartz pebbles and boulders -- assumed by geologists to be Pliocene river or beach deposits laid down in association with the formation of the coastal platform.  Because virtually all the land hereabouts is within the Castlemartin tank firing range, examination of the ground surface is not encouraged;  but rumour has it that deposits of quartz pebbles are quite widespread.  So the pebbles might have come from the existing land surface to the west of the find site, or from a clifftop area which has subsequently been destroyed by marine erosion.

I have no idea how thick or extensive this till layer might be, but it is certainly more than a metre thick in places.  The matrix is sandy and silty, and the deposit is not cemented, suggesting that it is probably Late Devensian in age.  If you look in detail at the photos, you can see pebbles of all shapes and sizes, and the main rock types represented are limestone (as one would expect), shales and mudstones, sandstones and grits (some of them clearly from Old Red Sandstone outcrops either offshore or near the mouth of Milford Haven), and flints.  I did not have time, on a very quick visit, to hunt for igneous pebbles -- but I would not be surprised if they are present in small numbers.

So the conclusion has to be that the ice topped the cliffs in the Stackpole Warren area.  We should not be surprised by this, given that till (apparently of Late Devensian age)  is also to be seen at Swanlake and on Caldey Island.

I'm intrigued by the similarities between the tills at Swanlake and Stackpole and on Caldey Island with the tills exposed in the low cliffs of the Isles of Scilly.  They look very similar, and they must surely be the same age.........

Coming soon: The Stonehenge Bluestones

Coming soon to a good bookshop near you -- the definitive guide to the great controversy!  A tale told (of course) with great sensitivity and discretion, featuring all the charismatic heroes whom we have grown to love over the years........

New title, new cover, and a great deal of new content, bang up-to-date.

Publication date:  1st June 2018


by Brian John

Greencroft Books, 256 pp, 110 illustrations.  Full-colour A5 paperback. 

Cover price £15.00
ISBN 9780905559940

Back cover blurb:

The mysterious bluestones of Stonehenge have caused heated debate for a hundred years, following the discovery that they came from West Wales.   Were they quarried and carried on sledges and rafts all the way to Salisbury Plain by our Neolithic ancestors?  And did the famous monument ever look as immaculate as the archaeologists have imagined it?

Following a meticulous examination of exciting new research from Stonehenge and West Wales, earth scientist Brian John tests a number of fondly-held beliefs to destruction.  He concludes that the bluestones are all glacial erratics, carried eastwards by the Irish Sea Glacier almost half a million years ago and gathered up not far from the monument. 

This book is a detective story with a difference.   It will cause a fundamental reassessment of  “the science of the stones” and enhance our sense of wonder about the forces at work in the natural world. 

Sunday, 22 April 2018

The raised beach at Broad Haven South

The northern section of the raised beach platform in Broad Haven South bay.  This section -- in a more sheltered part of the bay -- is much influenced by the fracture patterns in the Cartboniferous Limestone bedrock, so the rock platform is discontinuous, with fragments broken up by deep gullies. 

The southern section of the rock platform, out towards Saddle Point.  Here, because exposure is greater and wave action more concentrated, the platform is more coherent and easy to examine.  The cemented raised beach is so thick and resistant to erosion that in places it roofs over gullies and caverns that appear to have formed more recently.

Apart from Poppit on the Teifi estuary, this is the easiest raised beach exposure to examine, at least in West Wales. The rounded cobbles in the beach are almost all made of locally derived limestone, but there is a lot of broken bedrock debris mixed in, which suggests a cold climate with cliff falls and periglacial slope accumulations in the period immediately following beach formation. In places there are shells in the raised beach gravels and sands, but because everything is cemented these are difficult to extract, let alone identify.   The assumption is that the beach itself probably dates from the last (Ipswichian) interglacial, and that the raised beach rock platform is quite probably older -- maybe it is very old indeed, freshened up over several interglacials when sea-levels seem to have returned to similar high "interglacial" levels.

Here are a few images of the raised beach exposures -- transformed into concrete because of the calcium-rich environment.

What of the stratigraphy?  It's difficult to discern, but in places we can see up to 2m of sandrock (probably blown sand either partly of fully cemented) above the raised beach, with fresh (uncemented) head or slope deposits above, and then with fresh blown sand and sandy loam at the surface.  There appears to be no till or other glaciation-related material at this site.  

There may be three head deposits in this sequence -- one (cemented) mixed in with the raised beach or closely associated with it; another (also cemented) interbedded in the sandrock; and another (uncemented) higher in the sequence, beneath the more modern blown sands and sandy loam.

If this sequence represents the full Devensian cold episode of around 80,000 years, the uppermost head probably represents the late-glacial episode of cold climate incorporating the Older Dryas and Younger Dryas (around 10,000 years ago) and the uppermost blown sands and sandy loam were probably laid down in the Holocene or "post-glacial period".  That would match the situation elsewhere in Wales and in South-west England and the Isles of Scilly.  But where in the sequence does the Late Devesian glacial episode fit?  Somewhere in the "sandrock" period?  I's a bit of a puzzle, but somebody will no doubt sort it out.......

PS.  I found some of my old records from many years ago, and this was the sequence I picked up from some of the exposures in the 1960's:

8.  Sandy loam and blown sand
7. Upper head (uncemented)
6.  (Missing)  Fluvioglacial sands and gravels
5. (Missing)  Till from Dewisland (Devensian) glaciation
4c.  Lower head (cemented)
4b. Cemented sands (sandrock)
4a. Head incorporating raised beach cobbles (cemented)
3.  Cemented raised beach
2.  (Missing) Older glacial deposits -- mostly destroyed
1.  Raised beach platform (complex modifications over several interglacials?)

Note that both the older and younger glacial sequences are missing here.  I was fairly convinced in 1970 that the cemented deposits were all pre-Devensian Glaciation, and that the uncemented deposits are Late Devensian and Holocene in age.

Saturday, 21 April 2018

The Bluestone Quarries -- a great gullibility experiment?

Neolithic bluestone quarry?  You must be joking, man.......

Below I have re-posted a blog from eight years ago.  Suddenly, hoaxes and practical jokes are right back in the frame again.  I have been pondering, on this wonderful warm spring morning, and have come to the considered judgment that this whole bluestone quarrying business is actually a rather splendid "gullibility experiment" conducted by a group of smart academics who will, any day now, spill the beans. They will put out a statement saying:

 "Haha!  Fooled you all!  There never was any evidence for these things that we have labelled "Neolithic bluestone quarries"!  We just wanted to see how far we could go with a completely mad idea, inventing evidence, taking nice photos and drawing complex diagrams, placing it all in the learned and popular media, and promoting it through lectures and press releases.  Now we must come clean, and admit that we have just been having fun creating an edifice that has no foundations.  It has cost a lot of money and involved a great deal of effort.  But there has been a serious motive behind all of this -- and it has all been in the cause of science. The lesson is this:  do not believe everything that you are told by senior academics.  Test everything.  Scrutinize everything.  And draw your own conclusions strictly on the basis of what can be observed."

Frightening, isn't it, the extent to which a whole academic community can be swept along by something completely irrational?


Saturday, 27 March 2010

Two great hoaxes: Piltdown Skull and Bluestone Quarry?

Some see a bluestone quarry -- others don't.
Some see a Missing Link -- others see a hoax.

There was a piece on the telly the other day about the Piltdown Man hoax of 1912. One thing struck me in the commentary -- namely the "fertile ground" which existed in Britain at the time, providing perfect conditions for the hoax to take root, to flourish and eventually (in spite of the reservations of some experts) to become part of mainstream thinking. This is what one web site says about the hoax:

"Perhaps the most famous hoax was Piltdown man. In 1912, at a time when Darwin's evolutionary theory was new, and people were looking for missing links between humans and apes, someone planted two fake skulls which came to be known as Piltdown Man.
The part medieval man, part Orang-utang fossil was found, in the very English village of Piltdown in Sussex. Piltdown man's scientific name, Eoanthropus dawsoni, reflected its finder's name Dawson. To get a flavour of those times, the British Empire was still riding high, and Germany had their Heidelberg man fossil, Britain was desperate for a more important ' missing link' between man and monkey."

The key to this is national pride, and a desire in Britain to demonstrate that whatever important discoveries there were in Germany, Britain had even better ones, showing the world what wonderful ancient civilizations we had here, and what brilliant archaeologists we had to uncover them and to expound new theories of evolution to the world...... OK, petty, nationalistic, xenophobic and even absurd, but that was the world around the time of the First World War. Germany had Neanderthal Man, and now Britain had the "Missing Link" -- even more important.

So what about HH Thomas and the bluestones? Well, I have suspected for some time that Thomas might have been guilty of simplification and selective citation of his samples and his rock identifications, in order to flag up the Carn Meini area as the source of the bluestones. I have also expressed my amazement in earlier posts that he "got away with murder" in that NOBODY seems to have seriously examined his evidence or questioned his wacky idea that the stones had been hauled by tribesmen all the way from Presely to Stonehenge in a totally unique feat of Stone Age long-distance transport. And why did people not scrutinize his theory more closely? Why, because there had been great discoveries about megalithic structures in Germany, and because British archaeologists were desperate to show that in these islands we had even more advanced prehistoric civilisations and even cleverer engineers and technicians.

Sounds absurd? I don't think so -- and a number of other authors have suggested that Thomas's idea was carefully put together around the time of the First World War as part of a national "feel good" strategy, and that the whole nation (and not just the archaeologists) just loved the idea when he announced it, and were disinclined to examine it carefully.

So Thomas became famous, then the bluestones became famous, and the "bluestone transport story" entered the mythology of Britain. It is still trotted out ad infinitum, even though there is even less evidence for it now than there was in 1920. And anybody who dares to question it, or to undermine our cosy assumptions about the extraordinary skills of our Neolithic ancestors, is likely to get short shrift from the archaeology establishment. Look at what happened to poor Geoffrey Kellaway.......

So was the Carn Meini / bluestone quarry / human transport story all a hoax? I think it's a distinct possibility. How much longer will it be before the whole mad idea about human transport is finally consigned to the scrapheap? Not long, I suspect, since the new geology being done by Rob Ixer and colleagues in the Stonehenge area is revealing so many new sources for the stones and fragments at Stonehenge that we are going to have to talk about 20 quarries all over western Britain, rather than one. And that would be to stretch things to a rather extraordinary degree......

All hoaxes have their day, and eventually bite the dust, leaving senior academics looking very foolish.

The Bluestone Enigma

After several reprints, this book has now sold out of stock.  English Heritage snaffled up the last 100 copies not long ago, presumably for the Stonehenge shop........

The book has been very popular, but since it was published ten years ago a great deal has happened, so it needed much rewriting and revision.

The new book will be coming soon.   Watch this space.....

Thursday, 19 April 2018

The Devensian ice limit in Pembrokeshire -- update

This is from a recent post:  

I'm still convinced that Devensian ice has affected Caldey Island and has left till there -- and that's just a few miles further east. If ice flowed over Caldey it might have touched Old Castle Head, but because of the military presence there it is out of bounds. I'm now rather convinced that Devensian ice flowed from the west towards the east in this area, and that the great cliff rampart of south Pembrokeshire was an effective barrier which prevented the ice from transgressing inland. The cliffs are for the most part about 35m high, with a further slope of about 10m in the tidal and sub-tidal zone before a gently sloping sea bed with considerable irregularities runs further out into Carmarthen Bay.

There is a fabulous resource for looking at the sea bed here:

When the Devensian ice of the Irish Sea Glacier arrived in West Wales there was no sea and no coastline.  Instead, there was a steep rampart or coastal slope where the old cliffs had been in the preceding interglacial -- probably masked at least in part by the rockfalls and accumulated slope deposits built up during a long Early Devensian and Middle Devensian periglacial episode.  This is something I postulated (on the basis of a vast amount of evidence) in the 1960's -- and it is still accepted as valid.

So was this rampart or barrier prominent enough and continuous enough to effectively determine the position of the ice edge?  I am increasingly convinced that the answer is "yes" -- and that the ice, as it moved eastwards into Carmarthen Bay, did not have the strength or thickness to surmount this barrier, except in a very few locations.

Previously I have shown the Devensian ice pushing much further east up Milford Haven and across the western part of the Castlemartin Peninsula, but I am changing my mind on that...............  The reason is that on my recent walks on the S Pembs coast I have been reminded quite forcefully that the most common deposit on the clifftops and in coastal embayments like Manorbier Bay, Freshwater East and Swanlake is head -- a periglacial slope deposit (maybe not always periglacial) up to 4m thick and made up of broken bedrock in a sandy of gravelly matrix.  The thickness of the rockfall / slope deposit depends, as ever, on the characteristics of the local bedrock and the proximity of the old cliffline or bedrock source.  Here are a few examples of this material:

Devensian slope deposits (head) c 2m thick in the face at cliff face at Manorbier -- Old Red Sandstone (Devensian) bedrock.  Above the head, c 20 cms of colluvium or hillwash, and then 75 cms of blown sand and modern soil.

Slope deposits up to 3m thick in Swanlake Bay, close to the sandy beach.  Note pseudo stratification and variations in block size, which migh relate to environmental changes or to changes in bedrock source lithology.  Still to be investigated......

Relatively fine-grained slope deposits exposed in the cliff face on the eastern flank of Freshwater East Bay.  At the top of the sequence sandy loam or colluvium.

This is very interesting -- a nice example of a fossil ice wedge, exposed in the cliff near the beach in Manorbier Bay. The edges of the wedge are clearly demarcated, and the rock fragments that have fallen into it are standing vertically -- that is quite typical.  My interpretation here is that the slope deposits have accumulated during the Devensian cold episode, and that the wedge might have formed during permafrost conditions during the Younger Dryas.

All that having been said, there are certainly exotic stones and pebbles on all of the local beaches, some of them distinctly reminiscent of the volcanics of Western St David's Peninsula and Ramsey Island.  There are also scattered patches of what appears to be relatively fresh till, in locations which currently seem to defy rhyme and reason  -- some day we will no doubt work it out!  Some examples:

Exotic pebbles from the beach at Manorbier.  They are most likely to have come from degraded till deposits in the immediate neighbourhood.

Erratic pebbles incorporated into slope deposits in Swanlake Bay.  Have they come from very old glacial or raised beach deposits or from Devensian till reworked and incorporated into slope deposits since 20,000 yrs BP?

This appears to be undisturbed till, exposed in the cliff face at Swanlake Bay.  Note the abundant small pebbles from multiple locations in the clay-rich matrix.  The greenish cobble  does not appear to carry striations, but it displays abundant pressure fractures, some of which are conchoidal.  That suggests ice transport......

All in all, the evidence is stacking up that this south Pembrokeshire coast  was in some places unaffected by Devensian glacier ice, and in other places the ice touched the present coastline and left traces including coherent till.  The till is very reminiscent of that exposed in the Scilly Islands and on Caldey.  Watch this space.......

Wednesday, 18 April 2018

Swanlake Neolithic Bluestone Quarry?

It has been announced today, following a reconnaissance expedition to Swanlake Bay on the south Pembrokeshire coast, that Professor Dafydd ap Gruffydd ap Ifan ("call me Dai") has discovered what may be the first Neolithic bluestone quarry in south Pembrokeshire.  The precise location must be a closely-kept secret until Dai has sold the film rights to the National Geographic TV Channel.  From what we know about quarrying techniques from the meticulous work of the archaeologists at Rhosyfelin and Carn Goedog, virtually all of the key engineering features are present in this case.

The centre of attention must be the massive proto-orthostat of Devonian sandstone which we see left centre in the photo;  this was clearly intended for Stonehenge but was somehow left behind. It weighs about six tonnes.  It appears that when the Neolithic argonauts went sailing past on their rafts, on their way to the Bristol Channel, the locals flagged them down and offered them the stone at what they thought was a very reasonable price.  However, the Head of Acquisitions was not interested, having already obtained his quota.  So the locals chucked a few stones at him and his mates and sent them on their way.

Anyway, enough of archaeological narratives, and back to the evidence.  If you look carefully at the photo (click to enlarge) you can see the man-made pedestal of supporting rocks beneath the proto-orthostat, the threshold stone, the "railway tracks" used to facilitate extraction of the target orthostat, the slabs fractured and scratched by the movement of earlier stones dragged over them, the revetment and loading bay at the base of the photo, the chipping floor, and traces of the quarrying face at the top of the photo.  There is a vast amount of quarrying waste all around the proto-orthostat, suggesting continuous quarrying activity over many centuries.  Just off the photo is a clearly marked  trackway used to transport the stones across the beach towards the beached loading vessels.  In the bottom right corner of the photo clearly visible is the picnic table where the quarry workers ate their lunch between shifts.

We know that the Altar Stone came from the Devonian sandstones of South Wales.  Might it have come from this quarry?  The proto-orthostat in this photo looks remarkably similar.

We now await the arrival of the geologists at this site, confident in the knowledge that they will be able to provenance certain sandstone fragments and orthostats at Stonehenge to within a few square metres of the centre of this photograph.

 Speaking to Botswana Radio early this morning, Prof Dai said:  "This find is the culmination of a life's work.  We really have found the Chipping Sodbury of Neolithic Quarries. This will do wonders for my bank balance."

Monday, 16 April 2018

The World of Ice

I couldn't resist posting these two fabulous images from the World of Ice. No particular reason, other than the fact they are both very beautiful.   The top one shows icebergs trapped in sea ice -- I think the location is Scoresby Sund in East Greenland.  Not sure who the photographer is.....

The lower one is a wonderful iceberg picture from Russell Bevan -- location unknown.

Geologists slammed for ignoring "inconvenient" research

In a letter just published in "Geology Today",  I have had a go at geologists Rob Ixer and Richard Bevins for ignoring (in a paper in the magazine) those two "inconvenient" papers about Rhosyfelin that were published in 2015, and for pretending that there is no dispute about the "bluestone quarries."  That was not just forgetful or naughty of them -- it was a serious scientific misdemeanour.  In science you must be open to debate and criticism, and you MUST admit to the fact that your evidence is challenged by others.  Instead, as we know, Ixer and Bevins chose to portray the Neolithic quarry idea as established or unchallenged:

Anyway, last autumn I wrote a letter to the Editor of "Geology Today" about the Ixer and Bevins paper, and said in rather forthright terms that the paper should not have been published, because it chose to maintain the pretence that the "bluestone quarrying" hypothesis was universally accepted.  Anyway, the Editor and his colleagues got into quite a tizz and insisted on all sorts of deletes and minor edits, so that the letter ended up as a very mild rebuke.  I had to accept the "revised version" in the end, or it would not have been published.  The truth of the matter, of course, is that when a defective paper is refereed and accepted and published, and then heavily criticised, it reflects badly not just on the authors of the article but also on the shortcomings of the editorial process used by the journal itself.  When a paper has to be retracted, it reflects as badly on the publishing journal as it does on the authors.  So retraction is to be avoided at all costs.......

Edited version: Geology Today, 34 (2), March / April 2018
Dear Editor,

'Neolithic quarries'

I ─ům writing to make a complaint about the feature article by Ixer and Bevins entitled "The Bluestones of Stonehenge", in Geology Today (Vol 33, No 5, Sept - Oct 2017, pp 184-187).   I am disappointed that it has found its way into print, since some of its claims are unsubstantiated.

The geology is mostly acceptable, and we can live with some claims that are not actually well supported by the evidence. This is not the place to argue about details. But much more serous is the question of the "bluestone quarrying" issue.  This is not the first time that these two
authors have given the impression in the scientific literature that there is clear and undisputed evidence of ancient quarrying / Neolithic working at two Pembrokeshire sites, namely Carn Goedog and Rhosyfelin.   In two previous papers published in 2016 they referred to “Neolithic quarry
sites” and to “the Preseli quarries” without making any mention of the fact that in in the previous year two peer-reviewed papers had presented detailed evidence interpreted as showing that such quarries do not exist.

This latest paper, in the pages of Geology Today, has been submitted in spite of the fact that, in my view, the authors have been fully aware, for two years or more, that the “quarrying” evidence presented by Prof Mike Parker Pearson and his team does not withstand detailed scrutiny.

I was one of the authors of the “inconvenient” papers concerned, drawing on extensive knowledge of the Quaternary in West Wales. Detailed sedimentological, stratigraphic and geomorphological evidence was presented to show that all of the so-called "quarrying features" cited by Ixer, Bevins and others are entirely natural, and are fully to be expected in any Quaternary sediment sequence in West Wales where rockfalls are common. None of the cited features are exceptional.  Ixer and Bevins are quite aware of the contents of our papers, and have never challenged any of the field evidence which we have presented.  It seems to me that they have therefore ignored material which should have been cited, and have presented something as established when it clearly is not.

I should make it clear that this dispute between one group of earth scientists and another relates to the interpretation of field evidence at two sites, collected over a period of five years.  It has nothing to do with another ongoing (and vigorous!) argument about how, when and why an assortment of erratic boulders, slabs and pillars found their way from West Wales to Stonehenge.


Dr Brian John

Fig. 15. Carn Goedog, showing perched blocks, ice-moulded surfaces and broken bedrock. Natural, according to some, and a Neolithic quarry, according to others. (Image: Brian John)

Sunday, 15 April 2018

That famous "monolith extraction point" at Rhosyfelin

Perhaps the most frequently-cited of the "quarrying " or "engineering" features at Rhosyfelin is the so-called "bluestone monolith extraction point" near the tip of the spur, and very close to sampling point number 8 as examined by Rob Ixer and Richard Bevins.

Well, I was down in the valley again yesterday, and research continues.

Well there is not really a recess here at all, and given the nature of the bedrock above and below MPP's right hand, it is vanishingly unlikely that a bluestone monolith with dimensions 2m x 20 cm x 20 cm could have survived physical extraction by quarrymen from here, since the rock is criss-crossed with deep fractures. As I mentioned in a previous post, there are at least ten intersecting fracture planes within a very small area.  I'm amazed that the geologists did not point this out to Mike and his colleagues.  We are talking rock mechanics and common sense here.  

The other observation from my latest visit is that on the rock face from which the pillar is supposed to have been extracted, there is clear evidence that thin slabs of rhyolite have fractured and fallen away over a long period of time -- and not all on one occasion.  If you just look at the edges of the fractures on the rock face, some are quite young, others are moderately weathered and others are very old (rounded off and heavily abraded).  This little rock face has a complicated history, as any geologist or geomorphologist will confirm.  On the illustrations pasted below, click to enlarge.

And where is the debris from the flaky thin slabs or slices that have dropped away from this rock face?  Why, it has been thrown into buckets by the archaeologists and thrown away, on the basis that it was of no importance.  Very convenient.........

Much as I hate being a party pooper, there is only one conclusion to be drawn from these observations.  There is no monolith extraction point located here.   In other words, there has been no quarrying.

I'm convinced that if different parts of this face were subjected to cosmogenic dating analyses, the result would be a wide range of different exposure ages.  I believe that at least one sample was taken from here for analysis at Glasgow University a couple of years ago, and that the result should have been available last summer.  Whatever happened to that dating result?  Why has it not been published?  Why, in his 2017 lectures, did MPP not announce the date to the world?  

If the result had been favourable to the quarrying hypothesis, it would be out there by now, as sure as eggs is eggs.............. 

These "stumps" at the base of the rock face have been described as the solid rock remnants left behind when the monolith was levered away by the intrepid quarrymen.  But just look at how heavily abraded they are.  Like many other bedrock surfaces around the tip of the spur, they have been battered and worn down by powerful glacial meltwater streams loaded with sand, gravel, cobbles and even boulders.  The deposits left behind by these streams are located in close proximity to this point, and were exposed during the course of the archaeological excavations:

Saturday, 14 April 2018

A thousand published comments

This is quite weird -- I noticed the precise time when we went through the million mark on the web site hits, and today I noticed that we have published exactly 1,000 comments.  That indicates a fairly lively level of engagement or involvement -- so thank you all!  I am aware that many comments have also gone astray, so apologies for that -- there are various technical issues beyond my control, and I still don't quite understand why Blogger notifies me of some posts and not others, and completely blocks others as well.    The only posts which I have asked Blogger to block are anonymous ones -- and so if anybody out there does want to contribute, please do it under your real or assumed name.

Salisbury Plain before Stonehenge

On the matter of where those sarsens came from, I rediscovered a post from five years ago, when David Field was in conversation with Edward Pegler.  It's interesting to read it again...

Above is a sketch that David commissioned -- showing Stonehenge before Stonehenge, if you see what I mean.  Sarsens littering the landscape, gradually being collected and used......

What is the age of this supposed Phase One?  5,500 BP or thereabouts?

Heelstone in the distance, and the biggest sarsen vertical as well.  That's the one that was supposedly dug up out of that mysterious adjacent pit and that supposedly later fell down on top of the Altar Stone and broke in two.  Clearly Mike Pitt's latest theory which has picked up all this media attention within the last few days is really all old hat, in that David Field has said it all before........

David seemed to think that the artist had been a bit over-enthusiastic about all those sarsens, but this demonstrates that he has been thinking along these lines for quite a long time.  He also seemed to have been pondering whether -- in this reconstruction -- there should have been bluestones as well.  Now that would be a turn-up for the book.........

Friday, 13 April 2018

The arguments against the glacial transport hypothesis

I spend so much time on this blog pouring cold water on the human transport thesis that we might get the impression that the glacial transport thesis is never actually argued about, except in our comments  section.  In fact the matter of glacial transport is nowadays mostly ignored by the archaeologists,  who presumably want to maintain the pretence that nobody with an ounce of common sense bothers to talk about it since it is now deemed to have been impossible.

But there have been occasions in the not-too-distant past when the archaeologists (and their geological friends) have actually tackled the glacial transport issue head on -- and all credit to them for doing that.  The most intelligent and carefully considered article was published in 2011, as an update to a conference paper presented in 2008.  I did a post about this in 2014, but since debate is always to be encouraged, here it is again  -- even more relevant now, maybe, following all the recent fuss about "Neolithic quarries" and many other matters.

Below I give some extracts from the paper and the comments I added when this was first published.  Still all very relevant.

The "discrediting" of the glacial transport theory? Hmmm...

Thanks to Rob for sending me a copy of the following paper, published in 2011 but apparently based on a 2008 conference presentation -- and presumably updated for publication. It's a real curate's egg of a paper, but to the credit of the authors it does at least address the glacial transport theory rather than simply ignoring it!

Much of what is in the paper ifs familiar to followers of this blog. Here is the key info:

Mike Parker Pearson (Department of Archaeology, University of Sheffield).
Joshua Pollard (Department of Archaeology, University of Southampton).
Colin Richards (School of Arts, Histories and Cultures, University of Manchester).
Julian Thomas (School of Arts, Histories and Cultures, University of Manchester).
Kate Welham (School of Conservation Sciences, Bournemouth University).
Richard Bevins (National Museum of Wales, Cardiff).
Robert Ixer (Freelance geological consultant, Sutton Coldfield).
Peter Marshall (Honorary lecturer, University of Sheffield).
Andrew Chamberlain (Department of Archaeology, University of Sheffield).

No 1, 01 // 2011, pp 219-252


Whilst the sarsen stones of Stonehenge were brought from a short distance of about 30km away, the smaller bluestones originate in Wales, over 200km to the west. This remarkable distance for the movement of megaliths is unparalleled anywhere in the prehistoric world; some geologists have suggested that the bluestones were carried by glaciers in a previous Ice Age but others point out that there is no evidence for past glaciations ever having reached Salisbury Plain or even close to it.

This paper proposes that the bluestones were dragged by Neolithic people around 3000 BC, taking a largely overland route except for a crossing of the River Severn. This contrasts with the conventional thinking that the stones were carried on boats across the sea from Milford Haven in south Wales to southeast England. It presents evidence for new sources of some of the bluestones on the northern lanks of the Preseli hills, as well as rejecting the long-held notion that the sandstone Altar Stone came from the area of Milford Haven. Finally, it proposes that the Preseli bluestones were selected for transport to Stonehenge because they represented the ancestry of one line of Britain’s earliest farming migrants who arrived in the Preseli region shortly before 4000 BC.

Comment: The early part of the paper deals with the geology of the bluestones at Stonehenge and suggests matches with outcrops at many sites in West Wales -- and particularly at Carngoedog and Craig Rhosyfelin. (Note that this paper was written before the first digging season at Rhosyfelin in Sept 2011). This is not exactly a balanced discussion -- there is a very strong "quarry hunting" component to it, as there is in most of the other recent presentations from the archaeologists. At any rate, the thesis is that the bluestones were taken from West Wales to Stonehenge around 5,000 years ago and were first incorporated into Bluestonehenge prior to a further phase of use at Stonehenge itself. That of course is all fantasy, and there is no support for it on the ground, but that doesn't deter your average archaeologist these days........... I would also take issue with the rather partial discussion of erratic occurrences on Salisbury Plain, with "inconvenient" evidence (for example, relating to the Boles Barrow bluestone boulder and the sandstone chip in the Cursus) simply being dismissed as "unreliable". Contrast this assessment with that of Olwen Williams-Thorpe and her colleagues in two big 1991 papers.

There follows a discussion of the possible transport routes used by our heroic Neolithic ancestors -- it is completely fanciful, and the chosen route is the "A40" road route recently favoured by MPP rather than any route involving long sea journeys. Suffice to say that not a single piece of evidence is adduced in support of this idea.........

Now then. To the nitty gritty. Extract:


Not all scholars have been satisfied that the bluestones were brought to Wessex by Neolithic
people. In 1902, William Judd proposed that the bluestones might have been transported to
Stonehenge by glaciers during a previous Ice Age. More recently, Kellaway identified the surviving traces of glacial sequences deposited on the east side of the Bristol Channel around Bristol and Bath, perhaps during the Anglian glaciation around 450,000 years BP (1971). He subsequently modified his theory to suggest that the bluestones might have been moved during an episode of glaciation in the Pliocene, 2.47 million years ago, carried southeastwards from Preseli towards Salisbury Plain in the ice of a hypothesised prehistoric river (1991; 2002).

Yet the evidence for glacially derived material in the area around Salisbury Plain is still lacking. Green (1973) concluded from his study of pebbles in fluvial deposits of the rivers Wylie and Avon that there is a complete lack of glacially derived material in these river gravels. There is no evidence that any glaciers ever reached Salisbury Plain during any previous glaciation (Clark et al., in press). 1

Comment: As pointed out elsewhere on this blog, Green's evidence is highly equivocal. He did find erratics in river gravels, but simply assumed that they had come from post-Cretaceous rocks which once capped the chalk and which have subsequently been removed by erosion. There is evidence that glaciers might have reached Salisbury Plain at one stage -- 43 erratic bluestones and other "foreign" debris as well. And glacial modelling also shows that a glacial invasion of the chalk downs was perfectly possible from a glaciological point of view.

The glacial hypothesis is strongly supported by some (Thorpe et al., 1991; Burl, 2006: 145; John, 2008). There is, indeed, evidence for glaciation across a region stretching from the Isles of Scilly to the Bristol region and further north. Even so, it is estimated that any bluestone glacial erratics would not have been deposited closer to Stonehenge than 70km (40 miles) to its west, within the Severn valley in the area of Somerset. Any such bluestones would have still required human transport to bring them to Stonehenge, travelling a distance at least twice as long as that over which the sarsens were transported.

Various aspects of the archaeological evidence are taken as support for the glacial hypothesis
(Williams-Thorpe et al., 1997):

1. The builders of Stonehenge made no careful selection of bluestones to ensure geological
consistency. There may be as many as 13 ‘foreign’ rock types at Stonehenge, many still not identified to source within Wales and one perhaps being an otherwise unrecognised limestone monolith.

2. The inclusion of softer monoliths (such as the Altar Stone) is illogical, given that the harder
stones would have been much better suited to long-distance human transport.

3. If bluestones were so special, why were they not treated with care within the Stonehenge
landscape? For example, bluestone chippings from Early Bronze Age round barrows (2200-1500 BC) have been found only in the fills of the mounds rather than being placed as valuable artefacts within the central graves.

4. The distribution of Neolithic-Bronze Age artefacts of spotted dolerite is spread across
Wales, with a second concentration on Salisbury Plain and along England’s south coast. This second concentration could derive not from long-distance trade but from a local source of glacial erratics.

Each of these queries can be countered. It may be that the different geographical areas represented by the varying lithologies present at Stonehenge were significant because they symbolised the places of origin of those communities taking part in the enterprise. This could also explain why softer sandstone (the Altar Stone) was transported along with harder rocks. If the bluestones arrived at Stonehenge shortly after 3000 BC, there is no guarantee that their chippings would have had any cultural significance a thousand years later when round barrows were built. In addition, it may be that the monoliths themselves, rather than their ‘off- cuts’, were what counted in people’s minds. Finally, the distribution of spotted dolerite artefacts in southern England is likely to derive not from a local source of glacial erratics but from Stonehenge itself; Darvill and Wainwright’s 2008 excavation recovered evidence for prehistoric stone tool manufacture from worked-down bluestones (Tim Darvill pers. comm.). Stonehenge was thus the likely ‘quarry’ from which the southern English bluestone tools originated.

There are four further, major reasons why the glacial hypothesis, which argues the presence of a source of glacial erratics in the Somerset area, is likely to be flawed:

1. There are plenty of suitable stones from which monoliths could have been fashioned in the
environs of Stonehenge, considerably closer than 70km away – the supposed source of bluestone erratics. For example, the SRP’s excavations of the Cuckoo Stone and the Tor Stone at Bulford, both within a few kilometres of Stonehenge, located the solution hollows in which each of these stones had lain, thus demonstrating their local provenance. If proximity and minimal effort were the main principles for selecting Stonehenge’s stones, why bother to go as far as 70km to the west?

Comment: This is a circular argument. If the bluestones were lying around in the Stonehenge landscape, as is perfectly possible, of course they would be used for incorporation into a developing megalithic structure. We don't know whether the bluestones always were separated from the sarsens -- in some settings they might have been mixed up. And where did this idea come from that there cannot possibly have been any glacial erratics closer than 70 kms from Stonehenge? True, I have mentioned the occurrence of glacial deposits at Greylake and other sites in Somerset, and speculated about a possible ice edge near Glastonbury or near Westbury, on the chalk escarpment, but I have never doubted that the ice from the Irish Sea Glacier COULD have pushed a lot further to the east.

2. The stone circles and standing stones at Stanton Drew in Somerset, likely to date to the Neolithic, are close to the putative source of glacial erratics. Yet there is not a single bluestone among their varied lithologies, even though many of them were probably brought several kilometres to that site.

Comment: This is a flawed argument. The stones at Stanton Drew may or may not be glacial erratics, but the ice stream that affected the northern flank of the Mendips was not necessarily carrying the same assemblage of erratics as the ice that passed to the south. See my recent post on this.

3.The new evidence for bluestones in Stonehenge’s first phase indicates that primarily
bluestones, rather than sarsens, were acceptable to Stonehenge’s builders in 3000-2920 cal BC. This would suggest that the question of the type of stone was a matter of considerable concern for the Neolithic builders.

Comment: What "new evidence for bluestones"? Is this a reference to the non-evidence from Bluestonehenge? I don't accept that only bluestones were used in the early "bluestone settings" -- where are the facts that point to this?

4. The specific pillar-shaped monoliths selected for Stonehenge form only a tiny proportion of the available blocks of natural rock in the various outcrops of Preseli and its environs. The vast
majority of out-cropping stone is of blockier material unsuitable for detaching from the rock
outcrops as thin, 2m-4m-long natural monoliths. If bluestones were transported by glaciers as ‘free boulders’ (rather than smaller-sized erratic material; Thorpe et al., 1991: 148), the significant proportion of pillar stones at Stonehenge is at odds with the more varied boulder shapes to be expected as glacial erratics, deriving from the blocky material of the majority of Preseli outcrops.

Comment: This is a strange argument. Of course the bulk of broken stone around the tors of the Preseli district is blocky or chunky -- rather than pillar-shaped -- but I do not accept that the bulk of the bluestones at Stonehenge are long thin monoliths. Look at them carefully, folks. They are in all shapes and sizes, ranging from pillars to slabs to boulders -- and of the 43 we know about, we can only speculate on those which remain just as stumps. We cannot simply assume that those were pillar-shaped, just to suit somebody's hypothesis. And we don't know how many "inconvenient boulders" might simply have been destroyed or turned into axes.

In conclusion, although the glacial hypothesis remains unfalsified and cannot be rejected, most archaeological scholars consider human agency to have been the more likely cause of the bluestones’ movement. The debate between supporters of the two opposing theories has been vigorous and even intemperate; only further research at the source outcrops will resolve whether the bluestones were plucked by glacial action or quarried by Neolithic megalith-builders.

Comment: Having demolished the glacial transport hypothesis to their own satisfaction, the authors then say: "There are two current hypotheses to explain why the bluestones were brought by human
agency from south Wales." They summarise the "healing stones" hypothesis of Darvill and Wainwright and the "ancestor stone" hypothesis of MPP and his colleagues -- coming down heavily (as one might expect) in favour of the latter. So the emphasis here is on the "why" and not the "how" -- as the essential correctness of the human transport thesis is simply accepted as fact. That is just not good enough -- what's sauce for the goose is sauce for the gander. If this is supposed to be a balanced assessment of competing theories, where is the itemisation of the flaws in the human transport hypothesis to match the itemisation of the supposed flaws in the glacial alternative? Let me help:

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.

2. The builders of Neolithic monuments across the UK simply used whatever large stones were at hand.

3. If ancestor stones were being transported to Stonehenge, why have all of the known bluestones come from the west, and not from any other points of the compass?

4. There is no evidence either from West Wales or from anywhere else of bluestones (or spotted dolerite in particular) being used preferentially in megalithic monuments, or revered in any way.

5. If long-distance stone haulage was "the great thing" for the builders of Stonehenge, why is there no evidence of the development of the appropriate haulage technology leading up to the late Neolithic, and a decline afterwards? It is a complete technological aberration.

6. The evidence for quarrying activity in key locations is questionable, to put it mildly.

7. The sheer variety of bluestone types (I still insist the figure is somewhere near 30) argues against selection and human transport. There cannot possibly have been up to 30 "bluestone quarries" scattered about West Wales.

8. No physical evidence has ever been found of ropes, rollers, trackways, sledges, abandoned stones, quarrymen's camps, or anything else that might bolster the hypothesis.

9. Bits and pieces of experimental archaeology on stone haulage techniques (normally in "ideal" conditions) have 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. Aubrey Burl made this point forcefully many years ago, and it remains forceful today.

10. And if there was a "proto-Stonehenge" somewhere, built of assorted local stones and then dismantled and taken off to Stonehenge, where was it? Herbert Thomas thought it might have been near Cilymaenllwyd (south of Preseli) and now MPP thinks it might have been north of Preseli, either at Waun Mawn or Castell Mawr). So the great proto-Stonehenge hunt continues.......

.... and so on. To repeat. There is no evidence.

In conclusion, all credit to the authors for at least having a look at this issue in a nicely-presented paper, but a little more balance would not have come amiss.

Wednesday, 11 April 2018

Thus spoke Carl Sagan

In the past, we have discussed Occam's Razor and Hitchens's Razor in our discussions of the conduct of science, and I have been reminded that Carl Sagan has also spoken of this issue.  Here is an extract from Rational Wiki:

Extraordinary claims require extraordinary evidence

"Extraordinary claims require extraordinary evidence" was a phrase made popular by Carl Sagan. Its roots are much older, however, with the French mathematician Laplace stating that: "The weight of evidence for an extraordinary claim must be proportioned to its strangeness." Also, David Hume wrote in 1748: "A wise man ... proportions his belief to the evidence", and "No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." and Marcello Truzzi says: "An extraordinary claim requires extraordinary proof."

Either way, the phrase is central to the scientific method, and a key issue for critical thinking, rational thought and skepticism everywhere.

The evidence put forth by proponents of such things as gods, ghosts, Neolithic bluestone quarries, the paranormal, and UFOs is highly questionable at best and offers little in the way of proof. Even if we accepted what evidence there is as valid (and it is highly debatable if we should), limited and weak evidence is not enough to overcome the extraordinary nature of these claims. (I added the bit about the quarries…..)


Alice and Bob are two friends talking after school. Alice tells Bob that she watched a movie the previous evening. Bob believes her easily, because he knows that movies exist, that Alice exists, and that Alice is capable and fond of watching movies. If he doubts her, he might ask for a ticket stub or a confirmation from one of her friends. If, however, Alice tells Bob that she flew on a unicorn to a fairy kingdom where she participated in an ambrosia-eating contest, and she produces a professionally-printed contest certificate and a friend who would testify to the events described, Bob would still not be inclined to believe her without strong evidence for the existence of flying unicorns, fairies and ambrosia-eating contests.


OK -- maybe it is stretching things a bit to refer to Neolithic bluestone quarries in the same breath as fairies, unicorns, dragons and ghosts, but you get the general drift.......

I have also been pondering on how far out the quarrying hypothesis is when compared with all of the research that I have ever done.  In geomorphology, if you are looking at a new site, you assume from the outset that the story told in the landforms and the sediments will be the EXPECTED or NORMAL story, that matches what you pick up from all the other sites you examine.  That's how regional stratigraphies are established.  If you find anomalies, you then have to explain them -- maybe because there has been a landslide, or a blockage leading to the creation of a temporary lake, or some such thing.    

The problem which the archaeologists have faced, from the beginning, is that they arrived hoping to show that Rhosyfelin was exceptional or extraordinary.  It had to be a quarry in an area where there were no other quarries.   So it could not be validated by examining the site next door.  Indeed, examining the site next door might have been deemed dangerous, since if they had found exactly the same set of features, they would not have been able to call them "engineering features" at Rhosyfelin.  So the feeling was probably that it was best not to look, and to try and convince the world that what they were looking at was truly extraordinary.  The trouble is that everybody who looks at the site -- and the so-called "evidence" -- finds it not to be extraordinary at all.  Just perfectly normal rockfall features in a site where there is also a perfectly normal Quaternary sediment sequence.

Back to Carl Sagan:  
Extraordinary claims require extraordinary evidence

There is no way that anything from Rhosyfelin can cause us to take seriously the claim that this is where Neolithic quarrymen slaved away to win bluestone monoliths designed for transport to Stonehenge, or even to  Eglwyswrw.  There is nothing extraordinary.  The hypothesis is rejected.