Boots on the Ground vs. Sniping from a Mountain Lair: Testing Glacial Claims in North Devon

Brian John's April 3 post dismisses my Fremington Clay paper as a "pantomime," full of "scraps of geomorphological and glaciological nonsense," and probably written by AI. He devotes roughly half his post to an AI-generated analysis diagnosing my work as AI-generated. The irony writes itself — his AI mischaracterises my paper more egregiously than any fault it claims to detect, attributing to me positions I don't hold.

What the post avoids is substantive engagement with the actual work: the peer-reviewed Ramson Cliff re-examination, the Combrew Farm fieldwork, or the pending geochemistry.

The fieldwork Brian doesn't mention

On 2 November 2025 I visited Combrew Farm, relocated the key Fremington Clay erratic first described by Dewey (1910) and Taylor (1956), Taylor's No. 7, the well-rounded hyalopilitic andesite with possible Scottish affinities, still by the wall where Taylor recorded it. I photographed and measured it and arranged new samples from it, the most diagnostic clast in the suite. Results are pending and will be published.

In February 2026, Rob Ixer, Paul Madgett (one of the original discoverers, who first reported the Ramson Cliff boulder in QN No. 14, 1974), and I published a re-examination of the ~700 kg epidiorite at ~80 m OD on Baggy Point (Quaternary Newsletter 167: 13–19). Petrographic analysis aligns it with Cornubian greenstones, not northern sources. No pre-1969 record of it exists. Its evidential value for high-level ice flow should be substantially downgraded. Brian's post does not engage with any of this.

Fair points and concessions

Brian objects to my paper's characterisation of Bennett et al. (2024). He's partly right: my abstract groups them among "recent critiques," which was imprecise. Bennett et al. provide a major synthesis that supports a glaciolacustrine interpretation with caveats — they are not critiquing glaciation. I should have distinguished their review from my own sceptical position. My body text is more careful, and I stand by the point that their acknowledged ambiguities justify empirical testing of the critical claims, but the abstract wording could have been better.

He also objects to my description of Madgett and Inglis (1987) as characterising these erratics as "sea-ice proxies." That's a fair criticism. M&I 1987 is primarily descriptive — a careful catalogue noting the erratics "may have entered the area by a variety of mechanisms." My phrasing was an interpretive synthesis drawing on multiple sources and overstated what that specific paper concluded.

The ice-dam argument 

Brian's one substantive geomorphological point: if a proglacial lake stood at ~30 m OD, the ice dam must have been higher, making an erratic at 80 m unremarkable. But dam height and onshore ice extent are different questions. Sutherland et al. (2019) show that across New Zealand's Southern Alps, LGM proglacial lakes were dammed not by thick ice but by outwash fan-heads, massive aggradational gravel bodies built against the ice margin by high-sediment-load rivers. (See also, Perito Moreno, Patagonia; Nordenskiöldbreen, Svalbard). In the Taw valley, fed by Dartmoor meltwater carrying exactly this kind of coarse sediment load, a modest ice lobe at the estuary mouth supplemented by rapid outwash aggradation would produce a composite dam well above the ice surface. A 30 m lake does not require 30 m of ice, let alone ice extending to 80 m on an exposed headland kilometres to the west. The Ramson Cliff erratic remains isolated, with no supporting suite above ~30 m OD, and its petrography now points to Devon, not Scotland. See https://www.sarsen.org/2026/04/outwash-fan-heads-composite-dams-and.html for more details.

Where we are

The pattern is Popperian: identify the most diagnostic claims in the prevailing model, then test them empirically. The Ramson Cliff erratic has been tested and found wanting. The Fremington clast analyses are underway. Both are boots-on-the-ground work, conducted transparently with public notebooks.

I welcome engagement with the rocks rather than the rhetoric. The story continues through them.

Key References

• Daw, T., Ixer, R. & Madgett, P. (2026). QN 167: 13–19. doi:10.64926/qn.20517
• Bennett, J.A. et al. (2024). Proc. Ussher Soc. 15: 84–130.
• Madgett, P.A. & Inglis, E.A. (1987). Trans. Devon. Ass. 119: 135–144.
• Croot, D.G. et al. (1996). QN 80: 1–15.
• Sutherland, J.L., Carrivick, J.L., Shulmeister, J., Quincey, D.J. & James, W.H.M. (2019). Ice-contact proglacial lakes associated with the Last Glacial Maximum across the Southern Alps, New Zealand. Quaternary Science Reviews 213: 67–92.