Thanks to Tim Daw for a new post on his Sarsen.org web site about the Newall "erratic boulder" apparently found near Stone 8 by Col Hawley in one of his Stonehenge digs in 1924. Thanks too to Tony H for drawing my attention to it.
https://www.sarsen.org/2022/06/an-erratic-source.html?lr=1
This is a very welcome and important addition to the coverage on this interesting bit of evidence, following these posts:
https://brian-mountainman.blogspot.com/2022/02/newalls-ignimbrite-boulder-update.html
https://brian-mountainman.blogspot.com/2012/10/newalls-ignimbrite-boulder.html
https://brian-mountainman.blogspot.com/2014/08/stonehenge-mystery-of-striated-bluestone.html
Kudos to Tim for digging up the Hawley link and for reproducing those BGS photos at much greater clarity than I could manage. From examining the left-hand image (Fig 35), I would say, in reply to Tim's question about glacial striations, I will reply "Yes, they do indeed look authentic -- and I would provisionally accept that interpretation." Some of the grooves appear to be crossing, and there is no consistent direction, so I agree that they are probably not related to the internal structure or fabric of the rock -- which we would probably call rhyolite today. Here is an annotated version of the photo, at the largest magnification I can manage:
Possibly of greater significance are the two crescentic gouges on the edge of the stone -- these are generally excellent indicators of glacial transport and damage. But the shape of the stone is interesting too -- it has a series of facets or fractured faces, with the edges seriously damaged by abrasion. Some faces are more weathered than others, and I am intrigued by the setting in chalk rubble -- 25 inches below the surface, according to Hawley. He and the BGS experts were convinced that part of the stone had been worked by Neolithic or Bronze Age people trying to turn it into a stone axe -- but the photo captions indicate that the stone has had a long and complex history -- first in "cold acid water" (meaning exposure in an acid environment possibly somewhere in North or West Wales) and later in the chalky or calcium-rich environment of Salisbury Plain. This had led to the creation of patches of tufa on the stone surface.
Is this the smoking gun we have all been waiting for? I think it might well be -- since we now have the following 5 powerful indicators of glacial activity:
-- a small boulder or stone with 5 or 6 flattened faceted faces
-- rounded or abraded facet edges
-- different degrees of weathering on different facets
-- several visible crescentic gouges
-- a cluster of striations running in different directions
In addition, the weathering evidence cited by the BGS staff demonstrates a long and complex history in at least two very different environments. No way can this erratic be seen as a lump of rock quarried and transported by our heroic ancestors during the Neolithic.
More kudos to Tim for chasing down the Hawley reference to FOUR glacial erratic stones in close proximity in the same excavated pit. Three of them were made of rhyolite, and one of diabase (dolerite):
With the benefit of hindsight, looking again at Kellaway's published description of Newall's sample number RSN18, and of the boulder itself, it is now quite apparent that this is a vastly important piece of evidence. The "welded vitric tuff" is considered by Kellaway to most likely be of North Wales origin, although north Pembrokeshire / Mynydd Preseli cannot be ruled out. The description of the weathered layer of the stone -- work involving Harrison, Sanderson and Young, as well as Kellaway himself --is fascinating, demonstrating that the BGS staff took this find very seriously indeed.
Many people have never been to Stonehenge -- but they believe it exists because others tell them it does, and because they have seen photos and words on pages purporting to describe it. If you are going to believe in the existence of something, you need to have faith in the integrity of your sources.
We must remember that less than 50% of the surface area of the stone monument has ever been excavated. So goodness knows what still remains tom be discovered in the superficial deposits. And goodness knows what has been misidentified and / or thrown away. Hawley kept only those bits of bluestone that interested him, and threw the rest away -- maybe many of them are in the holes referred to as "Newall's Graves", as suggested by Ros Cleal et al in their big book (p 376).
And let's also remember that of the 43 bluestones (including remnants) at Stonehenge, no less than 26 are rough abraded and weathered boulders or slabs which would not be out of place in a terminal moraine or morainic litter close to any modern glacier snout. They look like natural and unaltered glacial erratics -- and there is no way that they can be interpreted as selected and quarried monoliths. Archaeologists are thunderously quiet on this point. The 4 smaller erratics referred to by Hawley and Newall belong squarely in this family of bluestones.
https://brian-mountainman.blogspot.com/2015/02/the-erratic-bluestone-circle.html
http://www.stonesofstonehenge.org.uk/search/label/Bluestone
To summarise. There is in my mind no doubt about the provenance of this stone and about its significance for some of the earlier researchers at Stonehenge. What we still do not know is its original provenance, probably on a rocky rhyolite outcrop somewhere in North or West Wales. There is a sample thin section somewhere with the number RSN18 -- ENQ 2305. Is it in one of the Newall collections in Salisbury Museum? We must hunt it down. Watch this space........
This is the analysis of the thin section made by KK Harrison, Chief Petrologist of the Geological Survey:
7 comments:
Everyone, including Tim Daw within his Sarsen.org site, ought to acknowledge the important
research made by Phillip Denwood in tracking down the IGS article and photographs first. I had made a separate effort, out of curiosity, to then locate writing on it contained in a book deposited in the Bath libraries ( where, incidentally, I started my librarianship career in 1970) but was initially mis-directed. Apparently, it resides in Bath Guildhall.
Yes, we have to thank Philip for kicking this whole thing off earlier this year! There is more work to do. Where is the "boulder" itself which was looked after by Newall in his home for many years and then passed to Geoffrey Kellaway? I'm sure Geoffrey will not have thrown it away..........And what happened to thin section RSN18? We really need to know where this boulder came from........ is the slide in Salisbury Museum in one of the Newall collections?
Adrian Green, Salisbury Museum Director, should be able to tell us, Brian. His email I put on the earlier this week Boles Barrow Post. It's also on the Salisbury Museum website.
Yes, I plan to check it out with him.
In the 3rd paragraph above the last photograph in your Post, you say: " Hawley kept only those bits of bluestone that interested him, and threw the rest away - maybe many of them are in the holes referred to as " Newall's graves" as referred to by Rod Cleal at al in their big book.
Well, Tim Daw has just (24th June) shown a photograph of where some of these " graves" are, in the Stonehenge landscape, on his Facebook site, in a new Post which is an update on how he discovered faint traces of what could be megaliths at Stonehenge.
Ros Cleal! I'm a long way from the book just now, but the site may be located somewhere in its pages.......
Yes, apologies to Rosemary Cleal, she's no Rod! And there's female as well as male - type stones at Avenue where she works in the museum.....
The other Comment that's popped up on that Tim Daw Facebook Post is from Simon Banton. More anon.....
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