Stonehenge Glacial Transport Theory Takes Another Major Hit

 New Quaternary Newsletter paper dismantles the Ramson Cliff erratic as proof of high-level ice flow

In the February 2026 issue of the Quaternary Newsletter (Vol. 167), Tim Daw, Rob Ixer and Paul Madgett (one of the original 1974 discoverers) publish a detailed re-examination of the 700 kg altered epidiorite block at 80 m OD on Baggy Point, north Devon. New petrographic analysis of the original thin section shows the rock is fully compatible with Cornubian greenstones from the Dartmoor metamorphic aureole, lacking any diagnostic Scottish or Welsh minerals. The boulder was first recorded standing upright in pasture, has no pre-1969 map or aerial photo record, shows no beach abrasion, and is the only claimed high-level erratic on the south Bristol Channel coast. The authors conclude its evidential value for Irish Sea ice overriding the cliffs “should be reassessed” and that it “warrants consideration as potentially a manuport rather than unequivocally glacial.”

A Bayesian analysis of the four key lines of evidence (petrography, upright position when found, unabraded texture, and lack of early documentation) starts from a neutral-to-glacial prior and updates sequentially. The combined likelihood ratios drive the posterior probability of pure glacial emplacement at 80 m OD to less than 0.3 % — vanishingly unlikely. Academics must phrase conclusions cautiously, but the data speak clearly: this boulder almost certainly required human transport to its present position.

Brian John has repeatedly used the boulder as key support for his glacial-transport theory for the Stonehenge bluestones. Since 2015 he has described it as “proof that ice-sheet override of Baggy Point” occurred, citing its height, supposed Scottish origin, and rough texture as incompatible with shoreline rafting (see his detailed 2015 posts here: https://brian-mountainman.blogspot.com/2015/01/the-erratics-at-baggy-point-croyde-and.html and https://brian-mountainman.blogspot.com/2015/01/baggy-point-erratic-at-80m-altitude.html). He repeated the claim in 2023 and featured it in his September 2024 table of “high-level erratics” to debunk the “myth of shoreline erratics”.

Another one bites the dust. The Ramson Cliff erratic — long presented as one of the strongest pieces of evidence for high-level Irish Sea ice reaching elevations comparable to those needed for bluestone transport to Salisbury Plain — has now lost its glacial credentials. The glacial-transport model for Stonehenge has just lost a central pillar.

Reference:
Daw, T., Ixer, R., Madgett, T., 2026.
A review of the Ramson Cliff erratic: evidence of high-level ice flow?
Quaternary Newsletter, Vol 167, p13
https://doi.org/10.64926/qn.20517