Another book review

Here is another prepublication book review from one of my readers -- Prof Danny McCarroll.  In this case, he is happy for me to use his name and to use the review as I like.  So here it is, exactly as he sent it:

REVIEW
‘The Stonehenge Bluestones’

I generally steer well clear of long-standing and at times acrimonious debates that lie beyond my own very narrow specialism. The great Stonehenge bluestone debate is a case in point and I have always kept an open mind on the question of their transport from Pembrokeshire to Wiltshire, either as glacial erratics in some early glaciation or by human transport in the Neolithic. The central problem, until recently, was that the strength of opinions far out-weighted that of the evidence on either side. In recent years, however, despite the continued refusal of English Nature to allow the stones to be properly sampled, there has been a flurry of activity and some light is at last being shed. The evidence, new and old, is reviewed by Brian John in ‘The Stonehenge Bluestones’,  published by Greencroft Books.

I always assumed that the Stonehenge ‘bluestones’ were all nearly identical igneous rocks derived from a very small area of the Preseli Hills in North Pembrokeshire. Recent detailed petrological examination of the samples that are available, however, suggests that, on the contrary, the rock types are very varied and must have come from many different locations. Since some of the igneous textures are quite distinctive, the likely source of some small bits of stone have been traced to specific locations, some of which have been archaeologically investigated to look for evidence of Neolithic quarrying activity. I had the pleasure to visit one of those sites, at Rhosyfelin, while the material was still exposed and was singularly unimpressed with the supposed evidence for quarrying activity; it all looked completely natural to me. At the time I thought that maybe I was just missing some subtle evidence that the trained eye of the archaeologist could discern, and that the many radiocarbon dates produced for the site would doubtless be used to critically test the quarrying hypothesis. Those dates have now been published in the journal Antiquity and in fact they lend absolutely no support whatsoever to the quarrying hypothesis; a fair appraisal would be that they actually falsify it conclusively. Unfortunately that is not the interpretation of the authors of what is, sadly, one of the worst papers I have ever read.

The other big advance of recent years, which is not really covered in this book, relates to the extent not of some early glaciation, where most of the evidence has gone, but of the very last major glaciation, the deposits of which dominate huge areas of Britain and Ireland and that have been well studied for decades. A few years ago I would have confidently stated that we knew the limits of the last (Devensian) glaciation. However, ‘Britice-Chrono’, a large interdisciplinary project funded by the Natural Environment Research Council under the leadership of Chris Clark at Sheffield has changed that view completely. The ‘established’ limits of the last glaciation were based on geomorphological evidence, like the distribution of erratics, but in this project a wider range of more expensive methods were brought to bear, including detailed off-shore survey, satellite and other remotely-sensed imagery and a whole raft of the most up-to-date dating techniques. It turns out that our ‘established view’ of the extent (and thickness) of Devensian ice was not just wrong but wildly inaccurate. The ice was much more extensive than we thought; in many areas where we mapped it as terminating on land it actually reached right out to the shelf edge.

No one is suggesting that the Stonehenge bluestones were carried to anywhere near Wiltshire in the last glaciation. If glacier ice was responsible it would have been in a much earlier glaciation and subsequent glaciations will have removed the evidence further north and west. The evidence for glaciation so far south and east has not really improved, perhaps the strongest being the presence of ‘bluestones’ in archaeological structures that certainly predate Stonehenge. Given the lessons of the Devensian glaciation, however, I am certainly not willing to state categorically that glacial transport of erratics from Pembrokeshire to somewhere near Stonehenge is impossible.

Having read, and enjoyed, ‘The Stonehenge Bluestones’ I have to admit that I still have an open mind. It seems to me that the evidence for glacier ice carrying big stones from northern Pembrokeshire to somewhere near Wiltshire is rather scant. However, the evidence for those stones having been carried by Neolithic people seems to be completely absent, and the supposed evidence for them being quarried at Rhosyfelin is, in my view, just plain silly. I am not tempted to enter the debate in earnest, I do not know enough about the Neolithic or pre-Devensian glaciations, but if I was forced to bet a pint of good pembrokeshire beer, preferably from the Bluestone Brewery at Cilgwyn, I think I would put it on the glacier transport hypothesis.

Professor Danny McCarroll
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Note:  I thought I was forthright enough in my appraisals of the quarrying "evidence" and in giving my opinion of that infamous "Antiquity" paper.  But Danny refers to the quarrying evidence as "just plain silly" and to the paper as "one of the worst papers I have ever read."  I would go with that. He also says that the radiocarbon and other dating evidence at Rhosyfelin falsify the quarrying hypothesis conclusively.  I would go with that too.

I also agree with him that there is no "smoking gun" as far as the field evidence is concerned.  We have two competing theories.    Theory One (the glacial transport theory) is a reasonable one, supported by some evidence; so it deserves consideration and further testing.  Theory Two (the human transport theory) is unreasonable in that it is unsupported by evidence and is simply underpinned by the supposition that Theory One is impossible;  it should therefore be rejected out of hand.  Think Occam's Razor and Hitchens's Razor.......