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Monday, 22 January 2018

Field et al 2015: the Stones


EH Plan of the stones, using the Petrie numbering system

Following on from our previous post:
https://brian-mountainman.blogspot.co.uk/2018/01/field-et-al-2014-landscape-and.html

we now come to

Reference:

David Field, Hugo Anderson-Whymark, Neil Linford, Martyn Barber, Mark Bowden, Paul Linford, Peter Topping, , Marcus Abbott, Paul Bryan, Deborah Cunliffe, Caroline Hardie, Louise Martin, Andy Payne, Trevor Pearson, Fiona Small, Nicky Smith, Sharon Soutar and Helen Winton (2015). Analytical Surveys of Stonehenge and its Environs, 2009–2013:
Part 2 – the Stones. 
Proceedings of the Prehistoric Society, 81, pp 125-148 

Abstract

Non-invasive survey in the Stonehenge ‘Triangle’, Amesbury, Wiltshire, has highlighted a number of features that have a significant bearing on the interpretation of the site. Geophysical anomalies may signal the position of buried stones adding to the possibility of former stone arrangements, while laser scanning has provided detail on the manner in which the stones have been dressed; some subsequently carved with axe and dagger symbols. The probability that a lintelled bluestone trilithon formed an entrance in the north-east is signposted. This work has added detail that allows discussion on the question of whether the sarsen circle was a completed structure, although it is by no means conclusive in this respect. Instead, it is suggested that it was built as a fa├žade, with other parts of the circuit added and with an entrance in the south.

Quote:  

"Eighty-six stones are visible at Stonehenge, including four stumps (Fig. 2); the 20th century excavations revealed a further ten buried stumps making 96 in all. These stones are coarsely divided between the sarsens, a hard sedimentary silcrete, and the ‘bluestones’, a catch-all term covering a variety of rock types of distant origin including spotted/unspotted dolerite, rhyolites/rhyolitic tuffs (Ixer & Bevins 2011; Bevins et al. 2012), volcanic ashes, a Devonian sandstone (the Altar Stone), and other sandstones (Thorpe et al. 1991)."

Concerning the sarsens and the recent attempts to designate "origins" on the Marlborough Downs and other distant localities: Quote:  "Flinders Petrie in particular, who carefully surveyed the stones and whose numbering system is used here, considered that the very position of Stonehenge may have been determined by the presence of a quantity of sarsen (Petrie 1880), while William Gowland (1902, 75, 115), who excavated at Stonehenge at the outset of the 20th century, similarly thought the stones were brought from ‘no great distance from the spot where the structure stands’. The geologist Prof. J. W. Judd (1902, 115–6) considered that they had been moved ‘only a few hundred yards’, while H. H. Thomas (1923, 242) also thought that they may have come from ‘the site of Stonehenge itself’. Johnson (2008, 121) has suggested that the Heelstone is too awkward and bulky a shape to move on rollers and it, at least, is unlikely to have travelled far. Equally the much smaller Station Stones could easily have a local origin: it is, after all, possible to find larger stones on Salisbury Plain without having to travel to the Marlborough Downs for them." 

The authors suggest that (on the basis of field examination coupled with analysis of the laser scan data) there are at least three different types of sarsen present, potentially indicating that the stones originate from several sources. On different colours: "the majority of the stones are grey, but Stones 54, 55, 101, and 156 exhibit an orange hue while Stones 53, 56, and 154 are purple-grey. "  So the interpretation seems to be that the sarsen stones have been collected up from all over the place, and have not come from a "targetted" quarrying or collecting area in the Vale of Pewsey or somewhere else far to the north.

This is interesting too, regarding stone weights:

"Stone 56 has been cited as weighing 30–50 tons yet, assuming a specific gravity of 2.4, this study calculates the above ground weight to be 23.06 tons, while the known below-ground ele- ment (2.52 m: 22% of the stone) would increase this to c. 28.1 tons, ie, substantially less than the previous estimate. The visible parts of sarsens in the outer circuit vary between 11.1 tons (Stone 21) and 23.5 tons (Stone 16), with most stones bracketed between 13 and 17 tons. Assuming that some 25% of these lie below ground, it can be estimated that the stones in the Sarsen Circle weigh between c. 14.75 and 31.5 tons, with an average of c. 20 tons."

"Assuming that dolerite has a specific gravity of 3, the above-ground weight of the pillars in the Bluestone Horseshoe ranges between 0.96 (Stone 61) and 2.16 tons (Stone 69). As excavation of stones 68, 69 and 70 revealed that between 33% and 40% lay below ground; their estimated weight might be 3.35 tons, 3.24 tons and 2.05 tons, respectively. Stones in the Bluestone Circle are typically not as tall as those in the Bluestone Horseshoe and, due to the numbers that are broken or fallen, it is not possibly to calculate their average weight. In any case they decrease in size towards the north-east. Stone 33, however, has an above-ground weight of 0.51 tons and excavation revealed that c. 1.03 m of it was below ground, allowing its total weight to be estimated at 0.82 tons. In contrast, the above-ground portions of Stones 49 and 31 weigh 1.11 tons and 2.04 tons respectively, and excavated profiles indicate that 39% and 45% of the respective stones was below ground, allowing their total weights to be estimated at 1.82 tons and 3.72 tons."

The great majority of stones (both bluestones and sarsens) have traces of working on them -- mostly associated with pounding with hammerstones of various sizes.    There is a long discussion of the evidence for tooling or working, but there isn't much discussion at all on which surface features may be natural and which are tooled, and on WHY a lot of time has apparently gone into bashing large stones with smaller stones.  Was the idea simply to turn irregular stones into rectangular ones which would be easier to build with?  But of course the evidence of mortice and tenon joints  and tongue and groove joints is compelling, and these are clear evidence that the builders were seeking to use woodworking techniques in a world of stone.  The feeling seems to be that the sarsens have for the most part been shaped for use at Stonehenge -- maybe involving different settings at different times, but that the bluestones may have been used and shaped elsewhere before being brought in to their present positions:  "All of the extant stones in the Bluestone Horseshoe and three in the Bluestone Circle (Stones 150, 36, and 45) have been finely dressed. However, scars resulting from the removal of tenons from the tops of Stones 67, 69, 70, and 72, and the repositioning of Lintels 150 and 36 as uprights, indicate that these stones have been reused from an earlier bluestone structure, probably once located in the Q and R Holes, though possibly elsewhere."  Where was this "elsewhere"?  As we know, MPP and various other authors are very attracted by the idea of a "proto-Stonehenge" made of bluestones  somewhere in the Preseli district which was dismantled and carted off, lock, stock and barrel to be incorporated into Stonehenge..........  And as incorrigibly as ever, after years of trying, they are still hunting for the mysterious site.

One thing which is disappointing about this paper is that the authors do not consider the extent of surface weathering on the bluestones, and what that might mean for their origins and dates of emplacement.  Neither do they consider stone SHAPES -- instead simply carrying on the promotion of the idea that the preferred shape for the "ideal bluestone monolith" was a pillar or column.  In doing that, they ignore the fact that most of the bluestones are not pillars at all, but boulders and slabs.  This is hugely important, suggesting that the stones are more likely to be a glacial erratic assemblage rather than a set of carefully selected monoliths.

Coming next, in another post:  interpreting the stone settings. (p 134)

20 comments:

Myris of Alexandria said...

"In doing that, they ignore the fact that most of the bluestones are not pillars at all, but boulders and slabs. This is hugely important, suggesting that the stones are more likely to be a glacial erratic assemblage rather than a set of carefully selected monoliths."

Or that since the bluestones were to be dressed that they (our Neolithic brave grunts)were more concerned with size rather than shape. A rather weak argument, better to concentrate on the inherent unsuitability of some of the lithics. MOST are roughly pillar shaped, those that are not, are small remnants.

Weathering profile, see above remarks on dressing. It is true that some of the dolerite debitage (ss)shows 'deep' weathering suggesting an undressed surface, not common though. Again what point is being made. The rocks were collected from weathered outcrops -collection determined, mainly, by the joint planes. Hence weathered.

Neither argument is very germane. Stick to the 'large' (a dozen or so, not your De Mille cast of thousands!!) lithological variety and suitability.

Shape and weathering are essential neutral in this debate. The stones have been dressed.

NOTE THAT THE DISPARITY BETWEEN 36,38,46 48 AND THEIR ABSENT DEBITAGE SUGGESTS NO SIGN OF THEIR DRESSING ON SITE. The debitage is destructive.
M

BRIAN JOHN said...

I doubt that even our brutish ancestors were so stupid that they carted off to Stonehenge all shapes, sizes, and types of rock, in the knowledge that once they got there they were going to be reshaped, and some of them smashed up completely. The chap in charge of costs and benefits would have stopped the operation completely, and told them to start again. There is no evidence that size was a consideration in "selecting" the stones, except for some arrangement in the bluestone horseshoe. The bluestones in the circle are a pretty shambolic assortment.....

Weathering -- what point is being made? This is fundamental. What age are the "dressed surfaces"? If they are the same age as the dated building phases at Stonehenge, fine -- but what if they are not? For a start, that would cast doubt on the assumptions that nearly all the stones are dressed, and secondly we would get a pointer to the time that has elapsed since the stones (or at least their upper surfaces) have been exposed to cosmogenic bombardment. Bring on the cosmo dating.......

Jon Morris said...

Good point. We know that the inner bluestones were more finely dressed than the outer bluestones. It's also reasonable to state that the inner blues were dressed for a different purpose to that of their eventual use in the Stonehenge monument. As far as I can tell, the debitage in the Stonehenge environs may be the result of post construction breakages with very little pre-construction working.

If the bluestones were transported by glacier, then it is likely that a proto-monument existed in the Stonehenge environs. Therefore, either a second proto-monument existed, or additional local glacial bluestones were sourced to add to the Stonehenge monument. If that were the case, then a local working/dressing area would be apparent in the Stonehenge environs (though this might be closer to the source location than Stonehenge)

However, if the bluestones were transported by human agency, then it is likely that the stones would be pre-worked close to the quarry and that either one, or two, proto-monuments existed in the Preseli environs: Even if the eventual monument(s) were intended to be at Stonehenge, pre-assembly would have been a logical thing to do.

If a proto-monument existed in the form of the more shaped stones then the need to transport would be related to either the meaning of the original monument(s), or some sort of meaning associated with the stone itself. Because the inner bluestone details do not appear to be related to their end-use at Stonehenge, this seems to suggest that the less-worked stones would also be transported for a reason related to their in-situ use at Preseli rather than the particular qualities of bluestone. This suggests that either a second more rough proto-monument would most likely have existed, or that the original proto-monument made use of highly worked and unworked stones in the same model.

Feel free to trash the above.. just a working summary of an idea.

Myris of Alexandria said...

No I agree that cosmogenic dating would be lovely, I have tried to interest people in dating the caliche on the debitage---would 'tell us when the debitage was produced.

Dressing of the stones,there is the Wymark et al (Free at, you have guessed it,)paper showing the detailed dressing on the stones.

Some surfaces will show that they are heavily weathered (do any orthostats show that??) some dolerite debitage does. What does that tell us, bugger all, that orthostats or part of orthostat were not dressed. That weathered joint blocks were selected.

Mute point, take a joint block of bluestone -do you dress at source and risk losing the dressing time were the proto-orthostat broken/lost en route, or do you carry a heavier block and dress in Wessex.

Cost benefit analysis would suggest you wait a millennium and then pay the Myceneans to build it for you. Bloody hell.

Do tell us now of the 'elf and safety regulations in force. What is the Neolithic equivalent of a clip board?

Cosmo dating at SH would be super but I think probably a waste of money. Better, as we can all agree, to get the EH or whatever they pretend to be these days to dig the buried orthostats so we can see the full range of lithologies.

Were I you and .... I would concentrate my arguments on the RANGE.
M

Jon Morris said...

Mute point, take a joint block of bluestone -do you dress at source and risk losing the dressing time were the proto-orthostat broken/lost en route, or do you carry a heavier block and dress in Wessex.

A sensible constructor would do preliminary dressing at source (same as we do nowadays for similar projects but with far fewer transport issues).

Why Mute? (moot?)

Neil Wiseman said...

Hi gang,

Based upon the differences in condition, size, detail of work on both inner and outer sets of Blues -- in addition to various lithologies -- has anyone considered that there may have been two discrete shipments of these stones?

Neil

BRIAN JOHN said...

Interesting point, Neil. Of course, those of us who do not believe in the "shipment" idea in the first place can argue, with even more conviction, that there were maybe two different "collection exercises". In the first, once the locals in the Stonehenge area had decided to do something daft (or noble) with lots of big stones, instead of using timber, they probably hunted around their territory and gathered up all the pillars and column-shaped stones they could find. Bluestones and sarsens -- a stone is a stone is a stone.........

Later on, when they were getting more ambitious, they kept hunting and used up all the rubbish stones too -- the boulders and slabs that they had rejected first time round. Then they used all of those up too, and eventually gave up on the whole project (unfinished) when they ran out of stones.

No more complex explanation is needed.

Steve Potter said...

Jon Morris, you are a man after my own heart. Moot point. Moot. Moot. Can't anyone use the English language any more?

BRIAN JOHN said...

We are very forgiving on this blog of those who steam off responses to something urgent an whose spellcheckers have a mind of their own. I STILL haven't trained my compute to stop turning the word "Devensian" into "Devonian" every time I type in the letters DEV........ Stupid machine. It is a very slow learner.....

BRIAN JOHN said...

ooops -- that should be "and"...... and that should be "computer"......

Jon Morris said...

Jon Morris, you are a man after my own heart.

Possibly.. but knowing Myris there will be a clever point about the wording that none of us know about... tis a trap I tell the.

I need to go over your way again Brian in the coming months. Neil's got a plan (I think) to be over here at about the same time. Must take a look at all this if there proves to be time to get up in them thar hills again.

BRIAN JOHN said...

Let's have a mountain expedition! Preferably when the water table has had a chance to sink a bit.......

Myris of Alexandria said...

Mute, tiny tiny sound, almost not worth saying. I would be sick of having to write sic (sic) every time I was punning.
Oh dear irony is too light a tool for some heavy weight English scholars
M

BRIAN JOHN said...

Or maybe, Myris, you meant to put "moat" -- something protective and circular, with unfathomable depths, and the occasional carp

Myris of Alexandria said...

Or perhaps mote (In God's Eye.) And the stones were beamed down.
Excellent novel, idea.
M
Did you mean carp or an anagram.

BRIAN JOHN said...

Isn't the English language wonderful? No, I meant carp as in carp...... Perhaps we should have a crossword puzzle page?

Myris of Alexandria said...

I was being bilingual and meant parc.
M

Neil Wiseman said...

The plan is in motion as we squeak, Jon ... as you well know.

Brian, I will be in Wilts in late May through late June, so Jon and I will pop over for tea and a look-see at the formidable Welsh Terrain.
Play your cards right and we'll drag along a certain Vagabond Geologist from Birmingham's dank cave of internet anonymity!
Hee Hee

Neil

Jon Morris said...

Mountain expedition sounds fun. Was pretty soggy when I was last there.

Myris of Alexandria said...

Is carp tasty??

Love Tilapia but hate that Viet Cong white fish.(hey hey LBJ how many kids.....; who would have thought that he was not only one of the good ole boys but one of the 'better' presidents.

M

The MPP monograph (SH Landscape??) is heading towards publication. Will be a number of volumes. Final stones are being unturned and all rationalised.