A review of the Ramson Cliff erratic: evidence of high-level ice flow?

 

The Ramson Cliff Erratic 2025 - Tim Daw

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

"Since the first report of a giant non-local boulder at the base of the Saunton Cliffs in 1837, the Saunton-Croyde area has been studied for its Quaternary deposits, including its far-travelled erratic boulders. All of those reported up to 1969 were at the base of the cliffs, hence the discovery of a non-local boulder at a high-level, significantly above modern and raised shore platforms, on top of Baggy Point was unexpected.

The Ramson Cliff erratic (Madgett & Inglis, 1987) is a large 700 kg altered epidiorite/greenstone block presently sited at 80m OD on Baggy Point on the north Devon coast. It has been, and is currently, claimed to be a glacial erratic being cited as evidence for high-level ice flow. Indeed, most recently, “In north Devon, however, in addition to the blocks in the till, an isolated block of epidiorite was found at about 80m OD on Baggy Point promontory [SS 4356 4070] by Madgett and Madgett (1974) which can only have been emplaced by an ice sheet.” Bennett et al. (2024, p 91).

Notably, this erratic has also been cited as potential supporting evidence for the hypothesis that glacial processes contributed to the transport of the Stonehenge bluestones, either partially or wholly, onto Salisbury Plain (John, 2024). As one of the few proposed glacial erratics—exceeding pillow-sized dimensions—that lies substantially above sea level along the southern margin of the Bristol Channel, its provenance and emplacement hold broader implications than just for regional Pleistocene ice dynamics.

Here we review the evidence for the claim that this boulder proves high-level ice flow. This includes the first detailed petrographical description of the boulder, suggesting a possible Cornubian (essentially Devon and Cornwall) origin, alongside examination of historical records, maps, aerial photographs and correspondence concerning the boulder's discovery and context. It is suggested that the evidential value of this boulder should be reassessed when considering the extent and altitude of the undoubted Irish Sea ice stream."

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