THE BOOK
Some of the ideas discussed in this blog are published in my new book called "The Stonehenge Bluestones" -- due for publication on June 1st 2018. After that, it will be available by post and through good bookshops everywhere. Bad bookshops might not have it....
To order, click
HERE

Wednesday, 23 May 2018

Another quarrying sceptic


This is from another pre-publication review of the book from a senior academic whose specialism is geomorphology.  He hasn't given me permission to use his name, but this is word-for-word!

First of all, I enjoyed reading the book. Thanks for the opportunity to do so. Your passion for the subject shines through! I also read The Bluestone Enigma. I can see why you wanted to produce an updated version of the story, in particular because of the excavations at Rhos-y-felin. I agree with you that the archaeologists have over-interpreted the flimsiest of evidence and invented an imagined Neolithic mindset based on very little (if any!) in the way of facts. They damage rather than enhance the transport origin hypothesis as a result. The Rhos-y-felin site itself is unconvincing as a Neolithic quarry, and so far no forthcoming convincing evidence of human industry there has appeared in print as far as I am concerned. You convince me that the Bluestones are actually a rag-bag of rocks of South Wales provenance and not rocks only from one or two locations in the Presell Hills. This does need to be emphasized and is not what most people would have in mind.

I must be honest and state that the above para is followed by an expression of doubt about the glacial transport thesis too, and my reviewer reiterates that there is no "killer fact" which demonstrated that glacier ice might have reached Salisbury Plain.  I agree with that -- and of course, in the book I refer to the balance of probabilitiy.  He cites a number of examples where the evidence of ancient till and ancient erratics is open to interpretation, and refers to assorted technical matters relating to glacier mechanics etc.  I'll do another post on these comments, and those from other reviewers, before too long -- there are many perfectly valid points that deserve to be debated.

That having been said, if one is unconvinced by quarrying and human transport, and unconvinced by the glacial transport theses, what is left?  Merlin the Wizard, or the activities of aliens?

Tuesday, 22 May 2018

Fossil ice wedge, Manorbier


This is a very fine fossil ice wedge, seen in the cliff face at Manorbier, overlooking the beach.   There's broken bedrock at the base, then about 1.5 m of pseudo-stratified ORS head, and about 50 - 75 cm of sandy loam and modern soil.  The wedge fill consists of sandy loam and small fragments of soliflucted ORS debris, with one or two larger fragments as well.  Note how many of the fill fragments are arranged vertically.  There is no till exposed here.    But clearly permafrost was present after the formation of the head horizon, at the time of sandy loam / colluvium accumulation.

Were features such as this formed at the peak of the Late Devensian Glaciation -- around 20,000 years ago, or much later, in the Zone III / Younger Dryas cold snap around 10,500 years ago?

Monday, 21 May 2018

New book causes much head-shaking....



The other day I had a very long conversation with Laura Geggel from Live Science in the USA, as a result of which she has now published a piece on the web:

https://www.livescience.com/62619-did-glaciers-carry-stonehenge-bluestones.html

Well, it's more carefully written than the piece in the Daily Mail!  As one might expect with science journalists, they get some things right and some things wrong, and then, having tried to present the views of the main protagonist (in this case, me) they have to balance it with the views of some outraged archaeologists.  So she has spoken to Josh Pollard (who is of course a leading proponent of Neolithic quarrying) and Barney Harris from UCL, who was involved in that lovely little stone-hauling experiment in a London Park, and they have given her all the reasons why glacial transport was impossible.

It will be a waste of time to get too involved in analysing everything that Pollard and Harris are reported as having said, but here are a few thoughts:

1. Pollard says that there are no moraines with big chunks of bluestone in them on Salisbury Plain.  I have never claimed that there are -- and indeed it would be vanishingly unlikely that depositional landforms with a strong surface expression could have survived half a million years of denudation.  Neither he nor I know whether there are patches of denuded or degraded till on Salisbury Plain, from which larger erratics (and maybe smaller ones too) have been collected.

2.  Pollard claims that there are artifacts including stone tools at Rhosyfelin and Carn Goedog which indicate that quarrying took place there.  Which stone tools?  Which artefacts?  He knows perfectly well that all of their "evidence" has been examined and disputed.

3. Are the bluestones pillar-like blocks, as Pollard claims? Some of them are, but the great majority are not. He says that smaller rounded boulders would be more likely to come from moraine, while pretending to be ignorant of the fact that most of the 43 bluestones are indeed smaller, rounded, faceted and heavily abraded.  In other words, they are typical glacial erratics.

4. Yes, dolerite is not very likely to preserve striations, but are rhyolites and sandstones more likely to hold striations if transported by ice? Maybe, but can somebody please show me a rhyolite or sandstone monolith at Stonehenge that does not carry striations?

5. "I would think [the rhyolite] would just disintegrate, to be honest, if it was in glacial deposits," said Josh.  Well, since there are no rhyolite monoliths at Stonehenge, maybe that is exactly what happened to them.

6.  "We know where the rocks started from, and we can see the extraction points?"  Excuse me, Josh -- but that is all fantasy.

7.  It's a bit disingenuous of Josh Pollard to claim that Newgrange and the Ring of Brodgar show evidence of long-distance stone transport. At Newgrange we are talking about small bits of quartz for the facing of the mound, and at Ring of Brodgar it is much more likely that the standing stones were for the most part glacial erratics.  The Vestra Fiold "Neolithic Quarry" has NOT been shown to have provided the stones used, as I have pointed out on this blog.

8.  Barney's point is a valid one -- when he says that if there were bluestones on Salisbury Plain at the time of the earliest stone settings, why were they not used?   Well, maybe they were.  Kellaway and many others have suggested that long barrows were robbed of larger stones when stone settings became all the rage -- but I thought it was now assumed that before Stonehenge was built there was no great interest in using large stones?  In the Early Neolithic, if stones had littered the landscape, they might well have been ignored.

9.  Let's forget about the "experiment in the park".  It was very jolly, but did nothing whatsoever to enhance our ideas about what happened in the Neolithic.  

All in all, the argument of the archaeologists seems to be this:  "Neolithic people were very clever.  If they had wanted to transport lots of bluestones from Wales to Stonehenge, they would have done it.  Therefore they probably did it...."

Sorry chaps, but that's not science.  It's fantasy, or something akin to religious belief......

Sunday, 20 May 2018

Seymour thesis on vegetation development in Holocene Preseli


I had not realised that this thesis from Philip Seymour had been digitised.  Anyway, it is a useful resource in that it describes environmental change since the last "cold snap", as recorded in the pollen record.  It's very tightly focussed, and I would have like to see a bit more awareness of the wider context; my sense is that there was a concentration at the time on working out what anthropogenic changes there were -- still a reaction, maybe, to the old ideas of environmental determinism......

Some of the sites examined were in the eastern Preseli area -- referred to by the author as the "Bluestone Area".  One interesting thing is the author's unswerving allegiance to the human transport thesis; he says there is so much evidence of human occupation and activity in the area around Foel Drygarn and Caen Meini that Kellaway's glacial transport thesis becomes "unnecessary" !!  Hmmm.... It was a long time ago, and we'll let that pass.

But a useful document nonetheless......


The environmental history of the preseli region of South-West Wales over the past 12,000 years

Seymour, W. Philip
Date: 1985

Citation:
Seymour, W. P. (1985) 'The environmental history of the preseli region of South-West Wales over the past 12,000 years', Institute of Geography and Earth Sciences, Aberystwyth University

Abstract:
The project involves a detailed palynological investigation into the environmental changes that took place during the Late-Devensian Lateglacial and Flandrian periods in the Preseli district of northern Pembrokeshire, south-west Wales. The approach adopted specifically takes into account the considerable diversity in terms of subenvironments and ecological habitats within the field area, with representative sites on the northern coastal plain, the exposed ridges of the Preseli Hills, sheltered valleys which dissect the uplands, and the flanking plateaux. In this manner and through definition of local pollen assemblages, unrepresentative extrapolations are minimised and an unbiased regional chronology has been produced. Results indicate that the distinctive climatic character of Pembrokeshire was probably manifest throughout the entire period under discussion. Thus, Corylus was locally present during the Late-Devensian Lateglacial Interstadial as it expanded from refugia to the south and west, and its extension very early during the Flandrian is also recognised. Conversely, Betula was relatively subdued during the Lateglacial and Early Flandrian, therefore suggesting that migration across the Cambrian uplands to the east was inhibited, particularly with the prolonged influences of the Loch Lomond (Younger Dryas) stadial on the high ground. The early establishment of mixed oak forest on the coastal plain is also recognised, although with some variation in its distribution within the field area. Apart from iiilocalised occurrences of carr woodland, however, the main Alnus rise did not occur until c. 6800 BP, when it is suggested that the rising sea-level may have been largely instrumental in creating suitable habitats on the littoral lowlands. During the later part of the period in particular, the variable activities of prehistoric populations are evident. Especially notable is the centre of activity during the Late Neolithic - Early Bronze Age near the site associated with the origins of the Stonehenge Bluestones. During the post-Roman period several cycles of increased exploitation and abandonment are recognised and these correlate well with historical evidence.

Saturday, 19 May 2018

Blanket peat on Waun Mawn


Exposure in the side of one of the drainage channels on Waun Mawn, on a gentle south-facing slope.  Here we see about 30 cm of iron-stained / gleyed regolith made of broken meta-mudstone debris with signs of cryoturbation.  Above that there is a thin layer with streaks of organic material, and above that about 10 cm of "blanket peat" containing a network of roots from the present-day turf layer at the surface, which is only 5 cm thick.  This is quite typical of the moorland hereabouts.  There is no sign of Devensian till at this location.


I have been taking another look at the "progress report" written by Prof MPP for the Rust Family Foundation:

http://www.rfamfound1.org/proj23find.html

In the section on Waun Mawn some stress is placed on "the date of peat formation" as a guide to the age of the sockets and the speculations surrounding stone removal.

As far as the biggest recumbent stone in the putative "proto-Stonehenge" circle is concerned, MPP says this: Its former stone socket is lined with many packing stones, and the peat fills of this socket indicate that the stone fell after the onset of peat growth."

On the other hand, "The smaller recumbent stone excavated in 2017 is on the east end of the arc and is just under 1m long (fig.4). The fill of the stone socket contains only brown loam and no peat, indicating that it filled before the growth of peat. Thus this stone came down before peat growth."

Then again:  "Emptied stone sockets with stone packing (but no surviving monolith) were identified beyond both ends of the arc of monoliths. The socket on the west side was a circular pit (0.85 m- diameter and 0.3 m-deep) containing large packing stones set vertically. The emptied socket had filled with brown soil before any peat formation. Deformation of the edge of the pit showed that its former standing stone had been removed towards the north."
"We discovered two empty stone sockets on each end of the arc, suggesting that these stones may well be the remains of a dismantled stone circle (figs.5,6). Megaliths were removed from these sockets before the onset of peat growth on this site, indicating that the stone
circle was dismantled in the distant past."

Tying things up and seeking to demonstrate (even at this very early stage) that there WAS indeed a stone circle here, on the basis of very scanty evidence, MPP concludes:  "It can be assumed that the lack of peat in three of the stone sockets indicates that their standing stones were removed before the growth of blanket bog. This is likely to have started growing around 3,000 years ago, which would indicate that the stones came down in the Neolithic or earlier Bronze Age."

This is all seriously confusing.  MPP suggests that blanket peat formation here did not start until 3,000 years ago, which would place it in the Sub-Atlantic climate phase (pollen zone VIII), well after the elm decline and 3,000 years later that the date normally assumed for blanket peat development in the uplands of Wales.  In most of the texts and in Gallego-Sala et al (2015) it is suggested that in upland Wales blanket peat development probably started early -- maybe as early as 7,000 years ago --  during the Atlantic "climatic optimum" when it was warm and wet.  It's also suggested that around 3,000 years ago, at a time of lower rainfall totals, and an increase in ash and birch cover, blanket peat development might actually have slowed.  After 3,000 years ago, blanket peat initiation occurred only in a smallish number of "less favoured" locations. 

In the Preseli uplands, we can reasonably assume that blanket peat development will have started at the same time as in the other uplands of Wales where there were acid soils and high precipitation rates.

Nothing seems to fit.  So we have a problem........

Could it be that the things being called "stone sockets" are not stone sockets at all, but are simply surface depressions or irregularities that have nothing whatsoever to do with standing stones?

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

Gallego­-Sala, A. V., Charman, D. J., Harrison, S. P., Li, G. and Prentice, I. C. (2015) Climate­-driven expansion of blanket bogs in Britain during the Holocene. Climate of the Past Discussions, 11 (5). pp. 4811­-4832.
ISSN 1814­9359 
Available at http://centaur.reading.ac.uk/48736/

PS.  The only detailed work on the development of vegetation in the Preseli - North Pembrokeshire area is a thesis by Philip Seymour, completed in 1985.  It can be seen here:
http://cadair.aber.ac.uk/dspace/handle/2160/3307

It's essentially a pollen analysis study based on a variety of upland and lowland suites, recording changes in pollen frequencies in sediment sequences.  It makes the point that the development of blanket peat bogs was never very great in this area, partly because of the lack of extensive plateau surfaces where waterlogging could occur.  So drainage -- mostly on gentle slopes -- was generally sufficient to prevent blanket peat development.  This is borne out by the generally thin peat layers which we find across most of the landscape -- 10 cm is a rather typical thickness.  Did all of the peat start to develop at about the same time?  And was that time associated with the Neolithic / Bronze Age increase in land clearance associated with forest burning and increased grazing activity?  Seymour suggests that this was the case, and that peat development before the Neolithic was not very marked, especially on fairly well-drained slopes.  He takes a rather anthropogenic approach, suggesting that peat and soil development was very much influenced by settlement and land use practices.  But there is a danger of circular reasoning -- was the environment causing man to make certain land-use decisions, or were cultural decisions shaping the environment?  Walker and McCarroll (in the QRA Field Guide for West Wales, 2001) take a more nuanced approach, agreeing that periods of peat development are associated with periods of increased rainfall, leaching, iron pan creation and waterlogging  -- while admitting that there is such a wide range of dates for the "onset of peat development" in West Wales that land use practices and settlement pressure must have some role to play.

It will be interesting to see what turns up when Waun Mawn is examined in greater detail.....





The raised beach platform at Lydstep Point

Looking east

Looking west

This is probably the most spectacular raised beach platform in Pembrokeshire -- it's about 100m long,  and up to 25m wide, and is tucked into the little bay between Lydstep Point and Whitesheet Rock.   It cuts across near-vertical strata, and appears to have nothing to do with any faults or fractures in the Carboniferous Limestone.  It's difficult to photograph because it is so extensive -- but everywhere it has quite a gentle gradient down from a distinct notch cut into the cliff slope, and at its outer edge there is a sharp drop down into the sea.

The most fascinating thing about this platform is that it is incredibly chopped up -- criss-crossed with fissures and chasms and undermined by caves.  It is actually quite difficult to walk across it because of these surface irregularities.  This, to me, indicates very great age --  the chasms, pits and collapsed caves are all signs of marine processes currently destroying something formed a long tome ago, at a time when sea level was rather stable, around 15-20 m above its present level.  I think that this raised beach platform is at a higher level than that of Broad Haven -- which is also cut into a limestone coast.

In spite of a thorough search, I found no traces of a raised beach here (cemented or loose) and no trace of any till.  But there is an area of about 10m x 10m where cemented limestone breccia rests on the platform and has survived subsequent erosion -- storm waves certainly get onto this platform when there is a southerly gale combined with a high tide.


Here the breccia is about 1m thick, and about 2m  thick in a few places -- and it has to be related to the limestone breccia on the neck of the small peninsula just 450m to the west.  The other interesting feature of the platform is the presence of a number of widened fissures and "slit caves" cut into the face of the old cliffline at the bach edge of the platform.  These are perfect locations in which animal remains and maybe other organic materials might be found.  These would be invaluable in working out the chronology of this site.


My instinct is that there might be raised beach cobbles -- and maybe ancient till -- beneath the cemented limestone breccia, waiting to be discovered.  The rock platform itself may even predate the Anglian glacial episode -- but it could of course be a composite feature, freshened up during several interglacial high stillstands of the sea.



Hut circle on Waun Mawn


The hut circle on Waun Mawn -- some stones visible, and others buried in the turf.  Too small to be a stone circle, and too big to be the remains of a cromlech, I suspect......

I went over to Waun Mawn to see if I could find the little hut circle shown on some of the old maps.  I found it all right --- it's very small indeed, less than 5m across, so if it was a hut it must have been very cosy.......

It's located about 200m from the single standing stone to the north of the Gernos Fach track.  Go directly upslope from the standing stone, and you'll see the small grassy mounds and the stones towards the eastern edge of a grassy area surrounded by low gorse bushes.


The single standing stone on Waun Mawr, on the north side of the farm track