I was encouraged to write this post by a couple of comments from one of my correspondents who is a very senior geologist.
The same strangely blinkered approach is apparent in the literature about the Newall Boulder. Ixer and Bevins insist on calling it a "joint controlled block" -- implying that its shape was determined by physical geological stresses and nothing else. When I showed close-up images of the boulder surfaces and edges to 11 glacial geomorphologists, these were their opinions:
https://brian-mountainman.blogspot.com/2022/07/a-glacial-clast-from-stonehenge-newalls.html( I told them nothing about the boulder and simply asked them for their opinions on how it might have been shaped and what its mode of transport might have been.)
1. If I had been doing a Reichelt shape classification I would have classed this as sub angular and typical of igneous clasts that have been dragged along the glacier bed.
2. I would say it has been glacially transported. That could account for the relatively smooth (abraded) surface and the other sub-angular surface and edges. There could even be some grooves on the abraded surface (upper image).
3. I would not be surprised if it is glacially transported. It looks to be the result of physical processes rather than chemkcal weathering. The light parts look hard and fresh and one side is flat. Corners and edges are neither sharp nor rounded. I could have picked it from a till in Bergen.
4. I am a bit less convinced. Looking at the right side of the first image the facets might be where cooling joints meet. That end is almost hexagonal. It is quite bullet-shaped though.
5. I would agree with my esteemed colleagues and say that there is certainly evidence for a possible faceted surface but difficult to say much more based on the photos.
6. In addition to the facets and chip marks that jumped out at first glance, the lower image to me has a slight bullet shape to it. Nothing definite from photos alone, and perhaps especially not from these two angles, but my very careful guess would agree with a subglacial transport path. Striae rarely preserve well (and on many lithologies don’t even form). Having said that, the clasts seem pretty weathered and battered.
7. Although quite hard to get a complete picture from just these two images, I’d say they seem to show a subrounded cobble/small boulder that is faceted, and has a shape that some people might say approaches a bullet-shape. I can also see some – what look like - chipmarks on some of its edges, the arrangement of which could indicate a responsible force from a single direction. From behind my wall of disclaimers and from within my cloud of speculation, I would probably guess that this boulder was subglacially transported. Striations on the faces would perhaps clinch it for me, but I could not see those in the images.
8. It's not possible to be definitive on the basis of these pictures alone. However, the presence of planar facets is consistent with subglacial transport. It would help if there were additional characters that might corroborate this, such as a stops-lee or double stoss-lee form. I guess there are no striations, or you would have mentioned them. Also rhyolite doesn't tend to striate.
9. My guess would be glacial. Not overly far travelled I’d say, but there does appear to be edge rounding and also chipping, with potential flat-iron faces. Looks like a lot of igneous clasts in tills in the north of Ireland.
10. I agree that this could be interpreted as subglacially transported boulder. Some rounding of the corners, but the facetted surface is not the best I have seen…if it has striations I would of course be 100% convinced.
11. Looks like a fluvioglacial clast. Definitely been in a fluvial system but only for short time as the degree of rounding is limited. The pic maybe misleading but I can see parallel lines -? Striations.
12. It looks partially faceted, edge rounded and abraded. The surfaces even appear to have some crude chattermarks/flip-outs. I cannot see any definitive striations but the lower image has an interesting set of linear marks that warrant a better image, though they may well be structural. I would say definitely glacially transported.
Experts consulted, in no particular order: Prof Neil Glasser, Prof Peter Worsley, Prof David Sugden, Prof Doug Benn, Prof Dave Evans, Prof Dave Roberts, Prof Jim Rose, Prof John Hiemstra, Prof Danny McCarroll, Prof Sven Lukas, Prof Jan Mangerud, Prof Steve McCarron. Some have indicated a willingness to be involved in future research on the boulder.
Here's another weird thing. In their 2025 tirade on the Newall Boulder, Bevins et al claim that the seven "diagnostic features"which I itemised in my 2024 article "could be simply generated by surface weathering exploiting internal discontinuities". That comment is frankly laughable, and even a GCSE geology student would not have got away with it in his end of term exams. I'm amazed that the journal editor and the reviewers did not jump on it from a great height.........
So what's going on here? It's pretty apparent to me that geomorphology -- and common sense -- are being muscled aside in pursuit of an agenda designed to minimise the importance of natural processes and to glorify the role of human beings in heroic rock transportation enterprises. I can understand archaeologists trying to do this -- but senior geologists????? Why???
The same extraordinary situation has arisen with regard to the erratic boulders of the Devon and Cornwall coasts, which Ixer, Bevins and their colleagues refer to as ice-rafted boulders or as monumental stones moved by humans -- in spite of the abundant evidence on the adjacent coast of ice
from the Irish Sea Ice Stream pressing some distance inland and leaving behind plenty of sedimentary evidence.
Bennett, J. A., Cullingford, R. A., Gibbard, P. L., Hughes, P. D., & Murton, J. B. (2024). The Quaternary Geology of Devon. Proceedings of the Ussher Society, 15, 84-130.
https://ussher.org.uk/wp- content/uploads/benettetal1584130v2.pdf
So, in the face of all of this, why is it that geomorphologists (apart from James Scourse, Chris Green and myself) have steered well clear of the Stonehenge bluestone debate? Well, partly it has something to do with academic etiquette -- university geomorphologists seem to have decided that this is naturally not their territory, and that archaeologists should be left in control of the agenda. Several of them have said to me "Oh, I can't say anything really useful because I am not sufficiently immersed in the debate and am therefore ill-informed." Others might have decided that the issue is too hot to handle!!
That's a pity, because geomorphologists do have special skills and have something unique to contribute to the debate. Their opinions on the shapes and surface characteristics of the bluestones and the sarsens would be invaluable, in print and on the record. We also need more opinions on the traces of glaciation that exist in the South West Peninsula and on the possible routes and dates for bluestone transport. There are also opportunities for the employment of established techniques for the dating of exposed rock surfaces.
POINT TWO
One final point from my geological correspondent. He expresses his disappointment that the term "debitage" has been used by many people (including me) for the stony detritus found in the soil in and around the Stonehenge stone monument. He says that the term encourages circular reasoning, because not all of it has come from the human destruction or shaping of bluestone and sarsen monoliths. So the word itself encourages the belief that the "debitage" is a man-made layer that has some stratigraphic and chronological significance. I take his point. This is typical of the rather slack or slapdash thinking that characterises the whole of the Stonehenge bluestone dabate. I shall try to avoid the use of the term in future.
In similar vein, I have drawn attention to the circular reasoning involved in the interpretation of the bluestone fragments found in Stonehenge excavations. Almost always, in Cleal et al (1995) and other publications, it is assumed that the presence of blustone fragments in a sediment layer MUST date that layer as having been formed after the first use of the bluestones on the site. That is a very dangerous assumption, which must in the past have resulted in many inadequate or incorrect dating exercises.
