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....
To order, click

Wednesday 30 October 2019

UCL Course on "The Age of Stonehenge" -- the perfect course for stupid students

Following instructions on what to think and what to do is 
not always a good idea........

Thanks to Tony for the link to this UCL course page: 

It's a 2nd / 3rd year course (not intended for freshers) on Stonehenge for students in the Institute of Archaeology -- so one would expect them to be reasonably well-read by the time they embark upon it.

Here is the essential info:

ARCL0078: The Age of Stonehenge
Year 2/3 Option, 0.5 unit

Coordinator: Prof Mike Parket Pearson

1. Overview

Stonehenge is the world’s most famous stone circle, dating from the Neolithic and Early Bronze Age. An iconic symbol of mystery and counter-culture, it has attracted attention from enthusiasts around the world who have come up with myriad and often bizarre interpretations of who built it, how and why. This half- module will explore Stonehenge and other monumental constructions within their social, cultural and landscape context, allowing Stonehenge to be understood within the world of prehistoric Britain and Europe from the adoption of farming to the development of copper and bronze metallurgy.

This course will examine the history of archaeological research on Stonehenge, and the nature of social change from the Neolithic to the Bell Beaker period and the Early Bronze Age. With many recent investigations of Stonehenge producing a wealth of new evidence, this course will bring students up to date on our knowledge of this fascinating period in prehistory. (my emphasis)

The course covers the prehistory of the British Isles between c.4000 and c.1500 BC, from the introduction of farming to the early Bronze Age. We will cover the Mesolithic background and Neolithic beginnings, the development of Early Neolithic settlement and monumentality, the changing material culture and monument styles of the Middle Neolithic in the prelude to Stonehenge, Late Neolithic settlements and society at the time of Stonehenge, followed by the arrival of the Bell Beaker way of life and the adoption of metallurgy in Britain. The chronological sequence will end with the Early Bronze Age modifications to Stonehenge during the gold-rich Wessex period. In four extra sessions, we will look at the development of Stonehenge, its relationship with Durrington Walls and Woodhenge, the procurement of Stonehenge’s stones, the Orkney sequence, and Stonehenge in the modern age.


How intelligent are the students on this course expected to be?  The answer to that is that they are assumed to be rather stupid, and incapable of independent thought, since in spite of the blurb about "bringing students up to date" the course literature is stuck in a time warp, together with the course leader, Prof Mike Parker Pearson.  In the section of the course on "Stonehenge and its stone sources" (reproduced below) the only acknowledgement of any disputes on the modes of bluestone transport is that reference is made to "the glacial transport theory" discussed by Kellaway in 1971 and Olwen Williams-Thorpe and her colleagues around 1991 - 2006. 

So the assumption is made by Prof MPP that his own 2nd and 3rd year students are simply too stupid to cope with the fact that the "glacial transport hypothesis" is alive and well, as explained in my two books published in 2008 and 2018:

Brian John, 2008 The Bluestone Enigma, Greencroft Books, 160 pp. 
Brian John, 2018 The Stonehenge Bluestones, Greencroft Books, 256 pp.

Both of these books have sold well at the Stonehenge Visitor Centre, so I assume that somebody thinks that they are reliable and worth reading!  But apparently MPP has not noticed that they exist.  Very careless.

Then there is the other assumption -- that UCL students are too thick to cope with the idea that the MPP "bluestone quarrying" evidence at Rhosyfelin and Carn Goedog has been rejected after close scrutiny and that his quarrying and stone removal hypothesis has been hotly disputed in peer-reviewed and published papers, as follows:

Brian John, Dyfed Elis-Gruffydd and John Downes. 2015. OBSERVATIONS ON THE SUPPOSED “NEOLITHIC BLUESTONE QUARRY” AT CRAIG RHOSYFELIN, PEMBROKESHIRE". Archaeology in Wales 54, pp 139-148. (Publication 14th December 2015)

Brian John, Dyfed Elis-Gruffydd and John Downes (2015a). "Quaternary Events at Craig Rhosyfelin, Pembrokeshire." Quaternary Newsletter, October 2015 (No 137), pp 16-32.

and this paper published online:

Brian John (2019) Carn Goedog and the question of the "bluestone megalith quarry"
Researchgate: working paper
April 2019, 25 pp.

DOI: 10.13140/RG.2.2.12677.81121
Carn Goedog paper.pdf

It does not do much for the reputation of a learned institution or University department if its most senior figure cannot bring himself to admit that his theories are hotly disputed, and assumes that his students are too stupid to cope with ideas that are not in line with "the gospel according to our head of department."

Anyway, I hope they all enjoy their lecture on 11th November, content in the knowledge that as long as they do not question anything they will get a nice archaeology degree in due course.

And would I ever give a job to the holder of a UCL Archaeology degree?  Sorry.  No way............


11.11.19 MPP lecture on Stonehenge and its stone sources

Week 7 Stonehenge and its stone sources

Stonehenge is built from two different types of stone: sarsen (the local silcrete) and bluestones (a variety of dolerites, rhyolites, tuffs and sandstones). Whilst the sarsen stone sources are likely to be local to within 20 miles of Stonehenge, the bluestones have their sources in west Wales. Three sources have recently been identified on the north side of the Preseli Mountains; one of these at Craig Rhosyfelin has recently been excavated and produced evidence of megalith quarrying. The choice of stones from such a distant source may have a major bearing on the purpose of Stonehenge.

Bevins, R.E., Pearce, N.G. and Ixer, R.A. 2011. Stonehenge rhyolitic bluestone sources and the application of zircon chemistry as a new tool for provenancing rhyolitic lithics. Journal of Archaeological Science 38: 605-22. Electronic resource

Darvill, T. and Wainwright, G. 2016. Neolithic and Bronze Age Pembrokeshire. Prehistoric, Roman and Early Medieval Pembrokeshire. Pembrokeshire County History volume I. Haverfordwest: Pembrokeshire County History Trust. 55–222.

Green, C.P. 1973. Pleistocene river gravels and the Stonehenge problem. Nature 243: 214–16. Electronic resource

Ixer, R.A. and Bevins, R.E. 2010. The petrography, affinity and provenance of lithics from the Cursus Field, Stonehenge. Wiltshire Archaeological and Natural History Magazine 103: 1- 15. Electronic resource

Ixer, R.A. and Bevins, R.E. 2011. The detailed petrography of six orthostats from the bluestone circle, Stonehenge. Wiltshire Archaeological and Natural History Magazine 104: 1–14. Electronic resource

Ixer, R.A. and Bevins, R.E. 2011. Craig Rhos-y-felin, Pont Saeson is the dominant source of the Stonehenge rhyolitic ‘debitage’ Archaeology in Wales 50: 21-32. Electronic resource

Ixer, R.A. and Bevins, R.E. 2017. The bluestones of Stonehenge. Geology Today 33(5): 183–7. Electronic resource

Ixer, R.A. and Turner, P. 2006. A detailed re-examination of the petrography of the Altar Stone and other non-sarsen sandstones from Stonehenge as a guide to their provenance. Wiltshire Archaeological and Natural History Magazine 99: 1–9. Electronic resource

Ixer, R.A., Turner, P., Molyneux, S. and Bevins, R. 2017. The petrography, geological age and distribution of the Lower Palaeozoic Sandstone debitage from the Stonehenge landscape. Wiltshire Archaeological and Natural History Magazine 110: 1–16. Electronic resource

Kellaway, G.A. 1971. Glaciation and the stones of Stonehenge. Nature 232: 30–5. Electronic resource

Meyrick, O. 1955. The Broadstones. Wiltshire Archaeological and Natural History Magazine 56: 192-3. Electronic resource

Meyrick, O. 1958. The Broadstones. Wiltshire Archaeological and Natural History Magazine 57: 76.

Parker Pearson, M. 2016. The sarsen stones of Stonehenge. Proceedings of the Geologists’ Association 127: 363

Parker Pearson, M., Bevins, R., Ixer, R., Pollard, J., Richards, C., Welham, K., Chan, B., Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge.
1331-52. Electronic resource

Parker Pearson, M. 2016. Secondhand Stonehenge? Welsh origins of a Wiltshire monument.
Current Archaeology 311: 18–22. Electronic resource

Parker Pearson, M., Pollard, J., Richards, C. and Welham, K. 2017. The origins of Stonehenge: on
the track of the bluestones. Archaeology International 20: 54–9.
doi: Electronic resource

Parker Pearson, M., Pollard, J., Richards, C.,Welham, K. Casswell, C., French, C., Shaw, D., Simmons, E., Stanford, A., Bevins, R.E. and Ixer, R.A. 2019. Megalithic quarries for Stonehenge’s
bluestones. Antiquity 93: 45-62. Electronic resource

Parker Pearson, M., Pollard, J., Richards, C., Schlee, D. and Welham, K. 2016. In search of the
Stonehenge quarries. British Archaeology 146: 16–23.

Piggott, S. 1948. Destroyed megaliths in north Wiltshire. Wiltshire Archaeological and Natural
History Magazine 52: 390-2. Electronic resource

Snoeck, C., Pouncett, J., Claeys, P., Goderis, S., Mattielli, N., Parker Pearson, M., Willis, C., Zazzo, A., Lee-Thorp, J. and Schulting, R. 2018. Strontium isotope analyses on cremated human remains from Stonehenge support links with west Wales.
Scientific Reports (2018) 8: 10790. Electronic resource

Thorpe, R.S., Williams-Thorpe, O., Jenkins, D.G. and Watson, J.S. 1991. The geological sources and transport of the bluestones of Stonehenge, Wiltshire, UK. Proceedings of the Prehistoric Society 57: 103–57. Electronic resource

Williams-Thorpe, O., Green, C.P. and Scourse, J.D. 1997. The Stonehenge bluestones: discussion. In B. Cunliffe and C. Renfrew (eds) Science and Stonehenge. London: British Academy & Oxford University Press. 315–18. INST ARCH DAA 410 W.7 CUN

Williams-Thorpe, O., Jones, M.C., Potts, P.J. and Webb, P.C. 2006. Preseli dolerite bluestones: axe- heads, Stonehenge monoliths, and outcrop sources. Oxford Journal of Archaeology 25: 29–46. Electronic resource

Tuesday 22 October 2019

Tasman Glacier dead ice wilderness

Moraine "wall" above the lake -- the debris is all resting on dead ice, and is very dangerous indeed.  Material is constantly sliding down into the lake.

The sharp crest of the main moraine ridge near the village.  Many people walk along the crest of the ridge -- not a good idea.  Note the dead-ice wilderness filling the whole of the glacier tough.

Scary!  Too many paths, too close to the edge.....

Annotated photo showing the moraine "wall" and the dead-ice chaos below.

Dead-ice terrain, in the Tasman Glacier valley.  Along the edge of the ice-dammed lake you can see that the terrain is all ice-cored.

Much as I love glaciers, I am genuinely scared of terrain like this. It's one of the most obvious signs of global warming.  Glaciers in all the high mountain regions of the world are melting catastrophocally, replacing areas of clean firm ice with this sort of landscape.  The Himalayan glaciers  are being transformed at an unprecedented rate.

Here is some Google satellite imagery:

Here we see the dead-ice wilderness from above.  The valley is between 2 and 3 km wide.  The meltwater lake is at the base of the photo, and the clean glacier snout is off the top of the photo.  The dead ice area covers about 24 sq km.

Close-up of part of the moraine surface.  Note the temporary meltwater lakes and the crescentic fractures where collapses have occurred.

The junction between the lateral moraine and the dead ice zone on the valley floor.  The track to the Ball hut runs on the outside of the moraine ridge, but people stop and clamber up onto the ridge crest far too frequently, just to get a better view.  Not a good idea. For the authorities, a tourist management nightmare.......

Remember, dear readers, that the Tasman Glacier surface was -- before it started its catastrophic melting -- located at the TOP of the lateral moraine ridge. Measurements suggest that the glacier surface has dropped by around 250m since 1880.  Even given that New Zealand glaciers are very dynamic, with rapid ice turnover, that is a phenomenal rate of glacier wastage.

Monday 21 October 2019

The Rhosyfelin till

Exposed till surface at Rhosyfelin -- Late Devensian

Exposed till surface in Erratic Valley, Antarctica -- modern

Geomorphology works through the use of analogies -- you initially interpret what you see on the basis of what you know from other situations. Experience is everything.  But then of course you have to go on and prove to others that your interpretation is the correct one, through the use of analytical methods of all sorts.  More and more sophisticated techniques come along all the time....

I was struck the other day by a photo of the surface of a hummocky moraine (meaning meltout till or flowtill) in the Erratic Valley, on the Antarctic Peninsula.   I thought immediately that it looked virtually identical to the till surface exposed during the Rhosyfelin archaeological dig.   I guarantee that you could switch the labels around, and nobody would be able to tell which surface is old and which is young, or which one came from where........

If you want a detailed description of the till, it's all in the QN paper published by Dyfed Elis-Gruffydd, John Downes and myself in 2015:

Brian John, Dyfed Elis-Gruffydd and John Downes (2015a). "Quaternary Events at Craig Rhosyfelin, Pembrokeshire." Quaternary Newsletter, October 2015 (No 137), pp 16-32.

The till surface that was exposed in the dig was so spectacular that it could not be missed, and yet it has still not been referred to in any of the archaeological papers by MPP and his team -- and not even in the articles written by geologists Ixer and Bevins.  Maybe if they had visited the site and examined the sediments, it would have helped.........  instead, the pretence has been perpetrated that somehow all of the sediments are associated with quarrying activity, and that they have no inherent interest unless they contain "evidence" of human occupation.  Strange world we live in.....

Friday 18 October 2019

Dead ice terrain

Unterer Grindelwaldgletscher in the Alps.  Debris-covered snout with many additions coming from valley side rockfalls

Chukhung Glacier, Nepal

Erratic Valley, Antarctic Peninsula.  Exposure of surface till in an area of hummocky moraine

Crusoe Glacier snout, Axel Heiberg Island.  Bedrock exposures adding rockfall debris to mixed morainic and fluvioglacial materials

Khumbu Glacier, Nepal.  Ice-cored moraines

Fox Glacier, New Zealand

Rohn Glacier, Alaska.  Dead ice terrain on the glacier flank, with meltwater lakes

Bing satellite image of the terminal moraine loop and dead ice terrain, Roslin Gletscher, East Greenland.  In 1962 we walked across that little lot -- it was a bit hairy at times.......

High-resolution Google Earth image of part of the same dead ice topography.  The glacier snout is just off the photo at top left.  Some of the trapped lakes are fed by debris-rich meltwater streams (buff colour) and others are isolated (blue).

Till characteristics and nomenclature

If you have ever wondered about diamictons and tills, and all things related to glacial deposition, you can always read the text by David Sugden and myself (if you can get a copy!) or --if you are short of time -- just take a look at this.  It's a fascinating little web site, with great illustrations:

I have always subscribed to the view that if something looks like a till, it probably is a till -- and that it is probably NOT an ancient deposit redistributed or rearranged under periglacial conditions over many thousands of years.  I am a man who likes his Occam's Razor;  the most parsimonious explanation of things is always what I look for, unless I am dragged away from it by something unexpected or spectacular.  The spat about the Caldey Island "diamicton" comes to mind..........

Since I have worked in so many glacier snout environments characterised by complete chaos, I am even rather sceptical about giving different till types names -- but I suppose there are always those who like to classify things.  I am equally cautious about the significance of fabric analyses, given that what happened here may not really have anything to do with what happened there, or a bit above, or a bit below.  In a chaotic ice wastage environment, anything can happen, and usually does.  Where a glacier is melting away, in a "dead ice environment", the environment is far from dead -- it becomes highly dynamic and mobile, with slumps and slides all over the place and a vast amount of sediment redistribution.  In these environments, field workers sometimes lose their lives when fragile ice bridges collapse without warning and where debris is suddenly mobilised on a steep melting ice slope.  If you happen to be standing in the wrong place at the wrong time time, too bad........

But some principles do apply.  We do have lodgement tills in Pembrokeshire, in the exposures of clay-rich Irish Sea tills at Abermawr, Mwnt, Whitesands, Druidston and elsewhere -- and in those exposures we can see deformation features and much else besides, if we subject the till to "micro-fabric analyses."

Elsewhere, and above the lodgement tills, we find something much more akin to chaos, in what was referred to in the old days as "rubble drift" --  patches of flow till, intermittent and discontinuous beds of sands and gravels, some blocks of incorporated frost-shattered slope breccia, and both subglacial and supraglacial meltout tills.  The tills that I have been describing on the Pembrokeshire coast, from multiple locations, have been emplaced in these rather chaotic environments at a time of catastrophic ice wastage -- I doubt that any of them have accumulated by lodgement on a glacier bed.

A textbook example of a flowtill  -- or is it a debris flow?  Does it matter?

A textbook example of a meltout till.  This one might be sublacial, but then again it might have formed supraglacially.  Again, does it matter?

Fresh till from Popplestones, Bryher, Isles of Scilly.  Probably a meltout till.

Stony matrix-supported till on the north slope of Preseli.  Probably a meltout till.

Clifftop till, Bullslaughter Bay, South Pembrokeshire.  Probably a meltout till.

Clifftop till near Ceibwr.  Another meltout till?

Stony clifftop till at Madoc's Haven.  Yet another meltout till.....

Controversy is the lifeblood of science

My little dispute with John Hiemstra and others over the nature of a small deposit on Caldey Island is quite fun, and it reminds me that disputation and controversy lie right at the heart of science.  One might even say that it provides the lifeblood of science....... and it is inevitable and necessary because, as Karl Popper pointed out long ago, science can only advance through a process of falsification.  If scientists concentrate on hypothesis confirmation everything stagnates -- and working hypotheses are replaced by ruling hypotheses.  We end up with "assumptive" and potentially corrupt research.  Now where have we heard that before?

I have another little dispute with James Scourse on the extent of glacier ice across the Isles of Scilly.  That's OK too -- and I hope James might agree with me that by testing ideas and scrutinizing evidence more closely, we will all get closer to the truth. 

When I sit down and think about it, I recall scores of disputes in my own field of glacial geomorphology,  some resolved and others not.  Right at the beginning of my career I had a dispute with Prof Fred Shotton over the age of the glacial deposits in Western Britain.  On that, I was right and he was wrong.  The dispute over the position of the Devensian ice edge in West Wales has involved scores of researchers over the years, and it still rolls on.  Right now, there is a somewhat acrimonious dispute (not involving me!) relating to the age of the last glacial ice to have affected Lundy Island:

How many scientific controversies are represented by the lines on this map?

Not so long ago there was another big row about the glaciation of Dartmoor.  Going back fifty years or more, Eddie and Sybil Watson had an ongoing dispute with virtually everybody else about the nature of the pseudo-stratified deposits along the Ceredigion coast.  There have been big arguments about the nature and age of the deposits covered by peat in the Somerset Levels.  That involved Prof Clarence Kidson and others.  In Scotland Prof Brian Sissons was notoriously disputatious, and argued fiercely with everybody about everything, verbally and in print!  Intense scrutiny was everything to him, and he scared the living daylights out of many a PhD student -- but he was not always right, and taught people to assemble their evidence properly and to interpret it carefully. Prof Dai Bowen had a huge row with Prof Danny McCarroll and many others about the use of amino acid dating techniques,  and the consequences of "over-interpreting" the results from an inadequately understood new technology.  The old ideas about matching erosion surfaces in the landscape, espoused by Professors Wooldridge and Linton and other senior professors were disputed, bit by bit, by younger geomorphologists, and were eventually abandoned on the grounds that they were far too simplistic and were not properly supported by field evidence.   I could go on a great length........


This is an interesting extract from a recent article:

Why do scientists disagree in the first place? One set of potential causes focuses on the experts themselves. One or more of the experts may be making an inaccurate claim because of incompetence (i.e., they are not experts at all [5]) and/or the fundamental limits of human judgment [6], or they may be intentionally or unintentionally biasing claims because of idiosyncratic attitudes, beliefs, or personal interests [7]. Another expert-focused cause might be different methodological choices that stem from individual scientists’ skills or preferences, or from historical developments in their respective fields or sub-disciplines. Alternatively, disagreements among experts within scientific fields may be due to irreducible uncertainty of the world itself and could be conceived of as a part of the normal process of science [8, 9]. From this perspective, it is inevitable that experts will disagree when confronting complex and uncertain real-world problems. It is the complexity and inherent uncertainty of the world that leads to disagreements about how to conceptualize problems, the research methods that should be used, etc. From a conceptual standpoint, these various expert- and world-focused reasons are neither logically nor practically mutually exclusive. For any given dispute among scientists there might be multiple causes, and these causes might differ from one dispute to another.


Why do scientists disagree? Explaining and improving measures of the perceived causes of scientific disputes.  By Nathan F. Dieckmann, Branden B. Johnson
Published: February 7, 2019

Here is another short extract from Wikipedia:

A scientific controversy is a substantial disagreement among scientists. A scientific controversy may involve issues such as the interpretation of data, which ideas are most supported by evidence, and which ideas are most worth pursuing.   Controversies between scientific and non-scientific ideas are not within the realm of science and are not true scientific controversies.[1]

This brings me, inevitably, to the dispute over the transport of the bluestones, which I am happy to acknowledge and play my part in, but which is ignored or denied by Mike Parker Pearson and his colleagues.  Are we involved in a scientific controversy, or are we not?  Well, if we say, for the sake of argument, that archaeologists are not scientists but storytellers, it might be argued that they are NOT involved in a scientific dispute!  

But of course there is a scientific dispute going on, and it has been running for almost exactly a century.  HH Thomas was a geologist, and so was Geoffrey Kellaway, and although they (as far as I know) never met, they certainly disputed the glacial and human transport hypotheses, as did other scientists including Olwen Williams-Thorpe and her team, James Scourse and Christopher Green.  More recently Rob Ixer, a professional geologist, has been very happy to dispute many points relating to his petrology and provenancing research, and also the glacial and human transport theses, on the pages of this blog, but not in published articles.  In those, whether writing with Richard Bevins as a specialist geologist or as a part of a team of specialists from many disciplines, he has studiously maintained the pretence that his ideas are universally accepted and that there are no disputes in progress.  Because he is a scientist and I am a scientist, this is a proper scientific controversy, and for it to go unacknowledged strays very close to the realm of scientific malpractice -- as I have said many times before.  

To a degree, I suppose we can partly forgive MPP and his archaeology colleagues because they are not scientists and do not fully understand what I am talking about...........   

Thursday 17 October 2019

Caldey Island -- a till or not a till?

In the summer issue of Quaternary Newsletter Prof John Hiemstra and several colleagues published a short note on the "diamicton" at Ballum's Bay on Caldey Island, which I have referred to on a number of occasions on this blog.

I have been convinced since 2011 that this deposit is a Late Devensian till, and I have not changed my mind.  Anyway, I encouraged John and others to go and have a look at it, which they duly did, and they decided that it is "probably" an old Anglian deposit which has been redistributed and redeposited under periglacial conditions in the Late Devensian -- some way from the nearest glacier.  Their article is available on Researchgate, where it can be scrutinised.

I didn't like their line of reasoning, and say so in the new edition of QN, just published:'KALD_EY'_IN_OLD_NORSE_WAS_LITERALLY_A_'COLD_ISLAND'_BUT_WAS_IT_UNDER_DEVENSIAN_ICE_QUATERNARY_RESEARCH_FUND_REPORT_BY_JOHN_HIEMSTRA_ET_AL

I didn't expect them to row back on their earlier opinions, and of course they have responded to my published points by saying that they still think they are right -- and to give a proper picture of their arguments I have added their comments after my own.  All good fun.

Of course, it's easy for them to say that I am basing my conclusions on "basic" rather than intensive fieldwork and on my detailed knowledge of the Pembrokeshire coastal exposures -- and they are right that I have no detailed laboratory studies or dating results to back up what I am saying.  The joys of being old, retired and disreputable!

But I will maintain, until something strong comes along to prove me wrong, that the Caldey till exposure is unexceptional, and that there are many other similar till exposures along the south Pembrokeshire coast -- as itemised on this blog -- that show that the Late Devensian ice pressed far to the east.  I repeat -- their explanation of the deposit as a "redistributed ancient till" is more convoluted than it needs to be, and is unsupported by any convincing evidence.

Of course, none of us ever looks at an exposure in a completely impartial way, and I dare to suggest that John and his colleagues may be just a little influenced, in their attitude to the Ballum' Bay exposure, by their interpretation of some of the deposits on the Gower coast, and at Rotherslade in particular.  They claim that in the cliffs on the south Gower coast there are great thicknesses of "redistributed till" which were rearranged beyond the edge of Late Devensian ice.  On balance, I disagree with that too, since I consider that the authors have not demonstrated in their paper that the studied deposits were not simply deposited (and maybe rearranged) in a highly dynamic and changeable ice wastage environment at or near the peak of the Late Devensian glaciation.........

That paper is here:

Hiemstra, J. F., Rijsdijk, K. F., Shakesby, R. A. and McCarroll, D. Reinterpreting Rotherslade, Gower Peninsula: implications for Last Glacial ice limits and Quaternary stratigraphy of the British Isles.
J. Quaternary Sci., (2008). ISSN 0267-8179

Preseli -- glacial deposits

Copy of a map by WD Evans (Plate 4 of his QJGS article) -- designed to show where the areas of exposed rock are to be found, but if you concentrate instead on the "boulder clay" or till areas, you can see just how extensive they are, both to north and south of the upland ridge.

I have been digging up some ancient papers and doctorate theses from the 1940's -- and have turned up some quite useful information.  Two researchers had interesting things to say-- WD Evans and JC Griffiths -- both of whom submitted doctorate theses to the University of London.

Sadly, it is not always easy to get at old papers -- the QJGS articles are still trapped behind paywalls, including this one:

The Geology of the Prescelly Hills, North Pembrokeshire
William David Evans
Quarterly Journal of the Geological Society, 101, 89-110, 1 October 1945,

Evans did not have much to say about glaciation, but Griffiths's thesis was titled "The Glacial Deposits west of the Taff, South Wales" (1940), and although in many ways it is a rather poor piece of research, he was convinced that there was at one time a Preseli ice cap, and that it may well have existed before the mountains were "overwhelmed" by Irish Sea ice.

This is an interesting map, from a 1984 NERC report on drainage in the Preseli Hills:

The stippled area covers all the land above 200m -- so this might give an indication of the extent of the intermittent ice-cap, which we have referred to on many past occasions.

Griffiths also mentioned blue clay till at Llangolman -- again I have described this before:

In 1904 TJ Jehu, one of my great heroes, described a clay pit at Llyn (Grid ref SN112274) or Fagwyr Owen, to the NW of Llangolman.  This was in open country, just above the 600 ft contour.  Jehu described the clay pit as containing "boulder clay" and of being 20 ft deep -- so deep that ladders had to be used to get in and out.  The clay is bluish and very tough, and was referred to back in 1904 as "india-rubber clay."  From the map and written evidence, there may have been more than one clay pit in the vicinity.

One thing that is very confusing, on the Geology of Britain viewer, is that on a small scale, the deposits both to the north and the south of the Preseli upland are coloured blue and labelled as "till", whereas when you zoom in the deposits to the south change from blue to a muddy sort of colour, with a different label.

The blue area is described thus:
Till (Irish Sea Ice) - Diamicton. Superficial Deposits formed up to 3 million years ago in the Quaternary Period. Local environment previously dominated by ice age conditions (U).

On the other hand, the area to the south has these words attached:
Head - Diamicton, Gravel, Sand And Silt. Superficial Deposits formed up to 3 million years ago in the Quaternary Period. Local environment previously dominated by subaerial slopes (U).

So on the one hand the till is deemed to be fresh, and on the other it is deemed to be mixed up with brecciated slope deposits and other materials.  I don't know that this distinction is based on any hard evidence -- I suspect that there is simply an assumption (based on the presumptions of Dai Bowen and others) that the till to the north of Preseli is Devensian and the till to the south is Anglian -- belonging to the mythical "Penfro Till Formation."

In other words, nobody knows what is going on, and somebody needs to sort it out.


Where did this till on the south side of Preseli come from?  How old is it?  I have assumed in the past that it is very old -- and therefore Pre-Devensian.  Now I am not so sure.

Wednesday 16 October 2019

HH Thomas and his glacial blind spot

Fig 20 from the Haverfordwest Memoir, showing the distribution of erratic boulders discovered by the field surveyors.  No ice limit is shown -- they knew that the ice flowed well to the east of Pembrokeshire.  The stippled areas represent areas of sands and gravels.

I have been looking again at the Geological Survey's Memoir No 228, published in 1914 and covering "The Country around Haverfordwest."  It also covers a large swathe of country eastward of the county town, as far as the border with Carmarthenshire.  It's noteworthy that the authors were Strahan, Cantrill, Dixon, Jones and -- here is the important name -- HH Thomas.

In the section of the memoir on Glacial Deposits, the "local details" are attributed to each of the key field researchers, and the section relating to the stretch from Whitland through to Haverfordwest was written by Cantrill and by HHT himself.  Thomas was clearly the man tasked with describing the fluvioglacial deposits of this stretch.  Like the others, he knew that glacier ice had covered the whole of the area and that it had flowed from Pembrokeshire out into Carmarthen Bay and well to the east.

In a previous post, I wrote this:

In the Pembroke and Tenby Memoir, as in the others relating to West Wales, a vast amount of evidence (collected by Thomas, Cantrill, Strahan, Dixon and Jones) is presented which shows that glacial deposits are widespread, and that erratic transport was not just possible but well documented. In the memoir, there is reference to erratics transported from Pembrokeshire to the Swansea area and to Pencoed in Glamorgan. Thomas knew that boulders could be carried by ice for at least two hundred miles -- and indeed he was perfectly familiar with big erratics of Scottish origin in Pembrokeshire -- and yet he deemed the transport of Stonehenge bluestones to have been impossible. 

I am struck yet again by the sheer illogicality of Thomas's position on the transport of the bluestones, since the human transport hypothesis with regard to the Stonehenge bluestone boulders flew in the face of all the evidence that he and his Geological Survey colleagues had so painstakingly collected over the years of fieldwork.  They deduced that ice carried spotted dolerite (diabase) and other igneous erratics from Pembrokeshire and Scotland at least as far east as Glamorgan -- but without any solid evidence to support him, Thomas argued that the glacier responsible could not have progressed any further towards Somerset and Wiltshire.  Weird.........

I'm forced to the conclusion -- yet again -- that Thomas was motivated not by good science but by the desire for notoriety, when he gave that famous lecture in 1921.

Tuesday 15 October 2019

The South Pembrokeshire "ice-free enclave" -- just a fantasy?

Gradually my confidence in the Late Devensian "ice free enclave" in South Pembrokeshire is slipping away, in the face of evidence building up by the day.   There's work in progress, but here are some enlarged sections from the Geology of Britain viewer:

Daugleddau confluence

Gravel terrace remnants (?) north of Haverfordwest

Sands and gravels and till patches around Clynderwen

Extensive patches of till around Ludchurch and Templeton

Till patches and sands and gravels in the Dale area

Till spreads and sands and gravels inland of the St Bride's Bay coast

Waun Mawn -- what next?

Quote from the 2018 Waun Mawn Report:

Ongoing plans

The Waun Mawn results are extremely encouraging, confirming the existence of a bluestone circle dismantled in prehistory, very likely to be one of the monuments from which Stonehenge was built. When the full analyses of scientific dating and geological analysis are completed, we plan an interim publication on these exciting results in the international journal Antiquity.

No further excavations are planned in 2019 but we hope to return for another season of excavation in 2020. In 2019 the project’s archaeo-astronomer, Prof. Clive Ruggles will analyse the stone circle’s astronomical attributes to establish whether it was oriented towards midsummer solstice sunrise or northern major moonrise.


We thank the Gerda Henkel Stiftung and the Rust Family Foundation for their financial support as well as UCL and the University of Southampton for their fieldwork contributions. Raw-Cut TV have also supported the project in recent years. The NERC Radiocarbon Panel awarded a grant for dating of 39 radiocarbon samples from Waun Mawn. Richard Bevins, Rob Ixer and Nick Pearce provided geological identifications.


This, of course, is nonsense:  "......confirming the existence of a bluestone circle dismantled in prehistory, very likely to be one of the monuments from which Stonehenge was built."   But we'll move swiftly on.

I'm intrigued by the sponsorship by Raw Cut TV -- so there is, as we thought, a documentary in the making.  The company says this about itself:  "we are the industry leader in crime documentary ‘blue light’ programmes."  Wow -- is Waun Mawn now confirmed as a crime site?  The biggest archaeological hoax of all time?  Remember, folks, you heard it from me first......

The only thing that might have happened this year?  Maybe Clive Ruggles checking on the archaeo-astronomy of the supposed standing stone circle?  Apparently he was planning to check whether the circle was oriented towards midsummer solstice or northern major moonrise -- I am greatly intrigued by the concept that a circle can be oriented towards anything at all, but there you go.......  but if you try hard enough, I suppose you can always find a stone or a slight depression that you might wish to call a stone socket aligned with something or other.  The search for significance is a wonderful thing, and can become an obsession.

I'm reminded of all the lovely people who take pictures of the setting or rising sun shining brightly beneath the capstone of Pentre Ifan (or some other cromlech) and between the supporting pillars, and then saying "Ah yes -- this was clearly the intention of the builders, and explains why the cromlech was built just here."  They never do get round to explaining what is significant about 8.39 pm on August 13th -- or whatever -- which was the time at which the "perfect" photo was obtained.  There's nowt so queer as folk.

It reminds me too of the Robin Heath school of number-crunching, circles, lines and triangles, in which he seems to suggest that all archaeological monuments (or rather, the ones he chooses to select) were built at precise points according to strict geometrical patterns -- although the "points" were hundreds of miles apart and although the Neolithic builders were not in possession of GPS positioning devices.  His suggestion seems to be that our Neolithic ancestors were such brilliant readers of the stars that they were able to precisely position their "meaningful megalithic structures" to within a few metres, and that the inhabitants of communities widely separated across these islands were all somehow tuned in to the same cunning plan devised by the God of Mathematics or some such deity.  Wonderful stuff.  "Sacred geometry" is the term Robin uses, claiming some sort of ancestry involving Prof Fred Hoyle.   But it doesn't do anybody any harm, and I suppose it keeps people out of mischief......

Robin recently ran a two-day course in North Pembs (£315 pp) on "sacred geometry" and his particular version of "proto-Stonehenge" -- I hope those attending got their money's worth!

A favourite post of mine relates to the position of Woolworths Stores, as mapped by Matt Parker.

Quote: " any sufficiently large set of random data it is possible to find meaningless patterns of any required accuracy.”

In any set of points plotted on a map (such as a map of Neolithic or megalithic sites in the UK) you can simply skip over the vast majority of the sites that happen to be inconvenient, and home in on the few that happen to coincide with the lines or corners of whatever triangle or other shape that you choose to demonstrate as "meaningful." The more data or plotted points you have, the greater is your ability to pull meaningless patterns from them.
Matt Parker had the locations of 800 Woolworth stores to work with. He was still able to find close "fits" with his chosen lines, distances, and geometric shapes, just as Robin Heath and others have done with their maps. The more random or precisely positioned points you have on the map, the greater the chance of finding "meaningful" patterns. If you just plot standing stones, or Neolithic henges, on a map, some geometric patterns will be found; but if you then add long barrows, round barrows, causeways, etc, your data set is greatly enlarged, and more and more "patterns" can be "discovered." If you want to increase your prospects of finding patterns even further, you can add in ALL prehistoric features, or "meaningful points in the landscape", such as Carn Meini, Glastonbury Tor, Lundy Island, Bardsey island, Caldey Island, or the tips of peninsulas or river mouths. You end up with hundreds if not thousands of points in the landscape, enabling you to find patterns everywhere, with close matches for triangles of various shapes and sizes, circles, straight lines, and curves.

You can play little games, just as they do in Playgroups and primary schools with very small children, by creating predetermined shapes (such as triangles of circles) and moving them around on your map with thousands of random points in it, and finding "fits." If the points of your triangle do not EXACTLY coincide with the "meaningful places" on your map, you can explain this away by using some pseudo-scientific phrase relating to degrees of confidence, or by saying "the fit is accurate to within 0.5%" or "the fit is almost perfect" -- or even by saying that the map itself is inaccurate, or that coastal erosion since the Neolithic has moved your crucial point from A to B. This is quite wonderful! You can do almost anything, and find "meaning" and "ancient wisdom" or "sacred geometry" in almost anything, as Matt Parker has pointed out.

This is not science. It is pseudo-science, pure and simple. Put another way, it is a little game that one might play with one's grandchildren. What is amazing is that some people actually write books about this sort of stuff, and that people buy them and read them, and are apparently swept away into a state of wonderment. What does it tell us about the human condition? Well, it tells us, I suppose, that the yearning for a rediscovery of "ancient wisdom" is still as strong as ever, that people have a strong sense of spatial awareness, and want to find patterns or "sacred geometry" in landscapes, or order where there is chaos. It also tells us that people are remarkably poorly educated and that they are just as gullible as our ancestors were in the Middle Ages.


This is all part of a continuum -- and, I suppose, part of the human condition.  When faced with features in the landscape some people will always look for significance, and go to enormous lengths to find it, assuming that there was, long ago, an ancient wisdom that we must try to identify or unravel.  I suspect that in reality many of the monuments that we like to call "sacred" were actually rather utilitarian, built not out of reverence for the heavens and the starry alignments but just because that was where Grandfather Dafydd lived, or liked to sit in the sun, or where some large stones happened to be lying around.