This week the Altar Stone is back in the news. A new paper in the Journal of Quaternary Science (Clarke et al., 4 June 2026, “From Highlands to Henge”) refines its source within north-east Scotland and models ice-sheet flow to test whether a glacier, rather than people, could have carried a six-tonne slab some 700 km south. It is a good paper and a good story. But a much quieter article in the latest Wiltshire Archaeological and Natural History Magazine may have more to say about the question sitting underneath all the headlines: were the Stonehenge stones brought by people, or dumped by ice?
That paper is Ixer, Bevins, Pirrie, Power & Pearce, “William Cunnington’s 1884 Stonehenge lithologies revisited” (WANHM 119, 2026, pp. 1–19). Its starting point is an archival rediscovery: in August 2021, 33 of the thin sections William Cunnington had “cut for the microscope” in the 1880s turned up in Devizes Museum, with their hand specimens catalogued separately in Salisbury. Cunnington had described some 460 fragments in 1884 — the first serious classification of Stonehenge’s “foreign” stones — and these slides are the type and reference material behind that work.
Here is the point that is easy to miss. Cunnington collected the last of the loose debitage from the Stonehenge surface before the twentieth century got to work on the landscape — before the military camps, the roads and railways, the car parks and the clinker-gravel paths. His collection is, in the authors’ phrase, a pristine lithological baseline: a census of what was actually lying on Salisbury Plain before any modern contamination.
And it contains no surprises. Every major bluestone debitage group is present (bar one rhyolite), in the same proportions as every collection made since — dominated by dolerite, Andesite Group A and the Craig Rhos-y-Felin rhyolites, with smaller amounts of Lower Palaeozoic Sandstone and a little Altar Stone. What it does not contain is a single exotic glacial erratic. As the authors put it:
“The plethora of exotic erratic lithologies hoped for by others is totally absent.” — Ixer et al. 2026
That is the whole glacial-transport hypothesis, tested against thousands of fragments from the cleanest sample we are ever likely to have, and coming back empty. If ice had carried a random scatter of Welsh and other rock to Salisbury Plain, this is precisely the assemblage in which we should expect to see it. We don’t.
The paper is not only negative evidence. The rediscovered slides yield the first proper petrographic descriptions of two buried stumps, Stones 32c and 61a; additional material from Stones 32 and 38; the type section for Andesite Group A (from 32c); and confirmation that the rare Dacite Group D really is bluestone debitage rather than a stray. For anyone following the orthostat-by-orthostat work, that is a quietly substantial haul.
The contrast with later material makes the baseline point sharply. The genuinely exotic rocks in the Stonehenge landscape — analcime dolerite, “Markfieldite”, Carboniferous limestone — turn out to be twentieth-century roadstone from Midland and Mendip quarries: industrial litter, not Ice Age cargo. Without Cunnington’s clean snapshot it would be far harder to tell the two apart. With it, the “erratics” dissolve into modern gravel.
So while the Altar Stone makes the front pages — and, for what it’s worth, even the new Altar Stone paper weighs glacial against human transport, finds the glacial route hard to sustain on the modelling, and cites fresh zircon-and-apatite work that found no glacial signature in Salisbury Plain river sediment — the Cunnington study does something less glamorous and arguably more decisive. It establishes, from the last undisturbed evidence, that the stones people keep hoping the glaciers brought simply aren’t there. One spectacular stone from Scotland is a wonderful puzzle. A whole assemblage with no erratics in it is, I’d suggest, the more important result.
References
Ixer, R.A., Bevins, R.E., Pirrie, D., Power, M. & Pearce, N.J.G. 2026. William Cunnington’s 1884 Stonehenge lithologies revisited. Wiltshire Archaeological and Natural History Magazine 119, 1–19. https://www.academia.edu/167889244/Cunningtons_thin_sections_and_rocks_revisited
Clarke, A.J.I. et al. 2026. From Highlands to Henge: refining the provenance and transport pathways of Stonehenge’s Altar Stone. Journal of Quaternary Science. https://doi.org/10.1002/jqs.70080
