The Ixer / Bevins "lumping" con

Oh dear -- yet another piece of "dusty box" geology from the infamous bluestone duo who like to call themselves the "pet rock boys".........

We have been here before -- many times:

https://brian-mountainman.blogspot.com/2023/09/when-is-bluestone-not-bluestone.html

This 2026 item seems to be essentially the same as something previewed last year:
https://brian-mountainman.blogspot.com/2025/10/more-on-cunningtons-rock-samples-and.html

Ixer and Bevins just love digging out ancient slides made decades ago by other geologists who have been involved in Stonehenge digs, describing and classifying them and making yet more changes to their list of bluestone lithologies -- while in the process promoting their view that none of the erratic material in the Stonehenge landscape can ever have been anywhere near a glacier.

Anyway, this is the reference to the latest contribution:

William Cunnington's 1884 Stonehenge lithologies revisited
Rob A. Ixer, Richard E. Bevins, Duncan Pirrie, Matthew Power, Nick J.G. Pearce
Wiltshire Archaeological and Natural History Magazine
1 Nov 2025

Abstract

The rediscovery in 2021 of 33 thin sections of mainly Stonehenge bluestones and the re-cataloguing of their associated rock specimens has allowed for a re-evaluation/re-examination and up-dating of William Cunnington’s 1884 ground-breaking account. All the major bluestone debitage groups are represented within the thin sections (other than Rhyolite Group E from orthostat Stone 48). The thin sections include the type material for the major Andesite Group A class of debitage (from Stone 32c) and single examples for the minor groups, namely the Altar Stone, Dacite Group D and a further example of orthostat Stone 38, the type sample for Dacite Group B debitage. Spotted and unspotted dolerites and Lower Palaeozoic Sandstone from within the stones and in the wider Stonehenge Landscape are also sampled. There is a lack of any other lithologies, the only non-local, non-bluestone materials are Greensand and sarsen.

The composition of the Cunnington bluestone assemblage as seen within the thin sections and by the rock specimens is the same as those collected in the 20th and 21st centuries and this is important as it was the last to be collected from the Stonehenge Landscape before significant human disturbance/contamination of the area; hence it represents a pristine lithological base line. The plethora of exotic erratic lithologies hoped for by others is totally absent.

Several points need to be made again.

1. The obsession with "modern contamination".  This is a typical straw man situation -- put something up just in order to knock it down.  The assertion that "modern contamination" is a major obstacle in the way of scientific accuracy or a widely held concern among Stonehenge researchers is a highly insular viewpoint.  For the vast majority of geologists and archaeologists working on Stonehenge, the landscape's modern gravel paths, car parks, and military camps were never considered a serious threat to working out the site's history.  The concept of a "pristine baseline" has no value.  In their re-examination of the William Cunnington archives, Ixer et al have used the phrase "pristine lithological baseline" to proactively bulletproof their own data. Because they were trying to provenance tiny flakes of debitage (rather than large, obvious standing stones), they framed Cunnington's 1880s collection as a "clean sample" to shut down any possible counter-arguments before they could be made. 

2.  This is all about lumping and splitting.  In geology, as in other disciplines, there are lumpers and splitters.  In their increasingly desperate attempts to support their human transport and monolithic quarrying hypothesis, Ixer and Bevins have systematically engaged in "lumping".  Their goal has been to show that the thousands of loose debitage flakes scattered around Stonehenge match a very restricted, narrow set of parent monoliths.  Obviously, if you can lump hundreds of disparate debitage fragments into just a few "coherent" groups, you can argue that they all came from a tiny number of precisely targeted human quarries. They assume, without any justification,  that all of the debitage has come from destroyed monoliths. This creates an illusion of neatness and strict human selection.  For example, in the Pont Saeson - Rhosyfelin area the debitage was initially deemed to contain various rhyolite subdivisions (Group A, Group B, Group C).  Ixer and Bevins then engaged in a prominent lumping exercise, combining these groups under a broader category to tie them directly to a single primary source -- which was then deemed to be a Neolithic monolith quarry.  They have done the same thing with the variable spotted dolerites from the Carn Goedog sill.  We should never forget that (a) there is no quarry at Rhosyfelin, and (b) that there is no matching foliated rhyolite monolith at Stonehenge.  There are similar problems with Group D albitised dacitic tuffs, altered gabbros, and a mixed bag of other volcanic fragments, limestones and sandstones.  Multiple rock types, and therefore multiple provenances

3.  On the matter of "spot provenancing" and the attempts to identify as small a number of actual monolith provenances as possible, Ixer and Bevins are essentially falsifying the record.  If you look beneath the label of any single Ixer/Bevins rock type or "group,"  the internal petrographic and geochemical variation turns out to be massive.  Within their single designated rock types, individual samples display wildly different internal fabric textures, mineral variations, altering degrees (like epidotisation or albitisation), and localized structures.   If a strict, unbiased "splitting" methodology is applied to the debitage, we end up with over 40 distinct rock types rather than a tidy handful. Many of these fragments—such as the highly altered gabbros, independent dacites, and unique sandstones—still cannot be matched to any surviving standing stone at Stonehenge.  Since the debitage types contain vast internal variation and include rocks that do not match the monument's orthostats, it heavily undermines the idea of clean, targeted human quarrying. Instead, it strongly implies multiple provenances.  As I never tire of pointing out (somebody has to do it) this degree of variation is exactly what you would expect from a glacier entraining detritus across a diverse volcanic landscape (like the Fishguard Volcanic Group terrain) and depositing a mixed bag of gravels, cobbles, and boulders on or near Salisbury Plain.  It also suggests that prehistoric builders weren't just bringing over perfectly uniform, prized pillars from two specific Welsh quarries. They were scavengers and opportunists who knew all about the minimisation of effort and cost - benefit analysis, as popinted out by Stephen Briggs.  Instead, they—or the glaciers that preceded them—were gathering a highly heterogeneous collection of "exotic" rocks from many different outcrops.  By lumping the rocks together, Ixer and Bevins enforce an artificial uniformity that obscures this geological variety, effectively fitting the data to support human transport while sweeping the inconveniently diverse "fingerprints" under a single taxonomic rug.

Very spotty dolerite at Carn Goedog

Very unspotty dolerite from Carn Goedog

4. The obsession with finding a "reslistically small" number of monolith provenances and quarries ignores a fundamental principle of sub-glacial geomorphology that completely upends the "quarry" narrative. Running through the work of Ixer and Bevins is a preoccupation with prominent, dramatic rock tors as the only possible source of megaliths.  This is  a profound misreading of how a moving ice sheet actually behaves, as I have pointed out in numerous posts.  The mainstream archaeological assumption is that if a stone more or less matches a specific rock formation, it must have been physically taken off the highest, most visible cliff face available.  The more prominent, the more sacred.  
Glacial geomorphology shows that the opposite to be true.  When a cold-based or thick ice sheet overrides a prominent rock tor, the ice is often frozen directly to the bedrock at the summit. This stagnant ice acts as a protective shield, preserving the tor's profile rather than destroying it.  In contrast, the deeper, lower-lying valleys and intervening depressions between the tors experience increased pressure and friction, leading to warm-based bottom melting, plucking and entrainment.  This  creates a highly varied trail of erratics.  This also explains why the chemical signatures of the Stonehenge debitage and the Waun Mawn stones are so untidy.

Carn Goedog -- eroded or protected by Irish Sea ice?

To conclude:  They say of the Stonehenge landscape "The plethora of exotic erratic lithologies hoped for by others is totally absent."  The plethora is there all right -- it's just that Ixer and his colleagues have chosen to ignore it in the context of a rather silly lumping stunt.