The Vexed Question of the Stonehenge Stones
Rob Ixer and Richard Bevins
British Archaeology, Sept-Oct 2014, pp 50-55
This is a carefully presented and beautifully illustrated article which gives the lowdown on the state of play -- albeit with a strong archaeological bias. Which is I suppose fair enough, since it is intended for consumption by archaeologists, who must not be subjected to any ideas that are too subversive.
The scene is set in the first few paragraphs, with mentions of the early geologists who are credited with recognizing the bluestones as different from the sarsens and with speculating as to their origins. The authors might have added that the early geologists also speculated that the stones had been transported by glacier ice. So the human transport theory is established as the only game in town....... and this unfortunate bias persists throughout the article, although it is of course as true today as it was in HH Thomas's time that there is not a scrap of solid field evidence to support it.
The glacial transport theory gets a later mention in the context of the work by Richard Thorpe and colleagues, published in 1991, and I am credited with "vociferously championing" it! Fair enough......... and here I am doing it again. Somebody has to do it, if the geologists won't.
There follows a description of the newer work, starting with Hilary Howard, continuing with Richard Thorpe and his team and then culminating in the latest research, more or less from scratch, by Rob Ixer and various colleagues, resulting in around a dozen new publications (most of which have been described on this blog). Rightly, the authors flag up the confusion that has reigned over the years because of changes in geological nomenclature. Indeed, the naming of rock types is tidier than it was, but still involves overlaps and names that may or may not be interchangeable. There are two really useful diagrams, one a site plan showing which of the bluestones have thus far been sampled and identified, and which have not (there are still a surprising number of "mystery stones") -- and another plan showing the firm locations from which pieces of rock in the debitage have probably come. What surprised me was that Carn Goedog is shown as a major source, although there are only seven fragments from it in the collection; that two other fragments have come (or might have come) from four locations, namely Carn Alw, Carn Breseb, Carn Ddafad-las and Carn Gyfrwy); and that one fragment might have come from Cerrigmarchogion or Craig Talfynydd. That's ten fragments and seven possible sources. Against that rather sparse record, there are 1,260 fragments that have purportedly come from the Craig Rhosyfelin area. Carn Meini (Carn Menyn) is excluded, although of course large quantities of the Stonehenge debitage have still not been analysed. So, as far as Tim Darvill and Geoff Wainwright are concerned, all is not yet lost....... and much more digging is needed at Stonehenge!
Under the heading "Ten Stones" Rob and Richard then claim that the old and long list of stone types at Stonehenge is down to the vagaries of nomenclature, and they suggest that the length of this list has been used to support the glacial transport hypothesis. Indeed it has, but shortening the list does nothing to invalidate the hypothesis or even to reduce its strength. The authors still insist on eliminating from their list all stones which are not monoliths or fragments and flakes, at either end of the size scale. I have said it before, and I will say it again, that this is illogical, and introduces a strong sampling bias into the process of geological investigation. When does a chunk of rock become small enough to qualify as a fragment or flake, and when does it become large enough to be counted as an "orthostat"? Mauls, hammerstones, packing stones, cobbles and pebbles, and odd lumps of rock recorded in the digging history are simply excluded from the analyses, presumably because they are deemed to be "adventitious" or "late introductions". When, in my estimation, these recorded stones from various provenances are included in the count, we are still up near 30 provenances..........
"Ten Stones" actually means "Ten Stone Types" -- and the authors proceed to itemise them and describe them. Two sandstone types -- neither of which comes from Mill Bay in Pembrokeshire. Four types of ash-flow tuff (stones 38, 40,46 and 48) -- all from different sources, probably in North Pembrokeshire, based on Richard';s great knowledge of the area. One type of "rhyolite with fabric" -- abundant in the debitage, and almost certainly from Craig Rhosyfelin. That's seven types so far, and seven provenances. A range of tuffs (cleaved and uncleaved) which are important in the debitage examined thus far. How many types, and how many sources? Let's assume four at least, but things get messy because stone 38 is included in this category as well as in the ash-flow tuff category. Spherulitic rhyolite -- a group of samples, or a group of provenances? Uncertain, but not Carn Alw. Then the dolerites, spotted and unspotted. Out of 60 samples, 14 have now been analysed, and a preferred source is Carngoedog, not Carn Meini. On the map of debitage provenances, there are six sites in addition to Carngoedog. I don't know about you, but when I add all of that up I get a total of around 18 different sites -- actually quite similar to the total proposed by Thorpe et al in 1991. And that still doesn't include all the other stones at Stonehenge that have clearly come from somewhere else. To me, this still looks like an assemblage of glacial erratics and around 30 different provenances.
Rounding off the article with "more questions" the authors give no further consideration to the glacial transport theory and nail their colours firmly to the mast regarding human transport. The question is simply this: "Which route did the stone-carrying parties follow?" By eliminating the presence of bluestones from Mill Bay, Steepholm and Carn Meini they argue that "the claimed Bristol Channel evidence does not stand up." I'm mystified by that statement, since there is abundant evidence of "foreign" or erratic stones all around the Bristol Channel coasts. So Richard and Rob argue that with Carngoedog and Rhosyfelin in the frame as possible quarries with nicely jointed rocks, a route to the north of Mynydd Preseli presumably on the lines of the latest MPP proposal is the one to go for. They also argue for a link with Callanish, Stenness and Brodgar on grounds that are tenuous and speculative to say the least.
A final point in the article is that there is an increasingly apparent disparity or mismatch between the orthostats and the debitage, with much of the latter (or that part of it which has been sampled) apparently coming from stones that are not (and maybe never have been) a part of the complex of standing stones. As the authors say, more surprises are to be expected.
All in all, this is a readable and stimulating article which brings quite complex publications to the attention of a non-specialist readership in a very attractive way. The illustrations are great too. So, congratulations to the authors and the journal. The debate rolls on!