The Fremington enigma

Map of the Fremington - Barnstaple area, from Stephens (1970) in the Glaciations of Wales volume edited by Colin Lewis, Ch 11.  It shows the outcrops of the clay-rich "Irish Sea till".

Brannams Claypit as it appeared in 1963.

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The Brannams Claypit section, from Stephens (1966)

In my previous post on the positioning of the Late Devensian "eastern terminus" of the Celtic Sea piedmont ice lobe, I mentioned the occurrences of till on the coasts of Devon and Cornwall.  In his chapter in the "Glaciations of Wales and Adjoining Regions" he devotes some space to a discussion of these deposits, and further evidence is contained in a paper called "Some Pleistocene deposits in North Devon" published in Biuletyn Peryglacjalny Vol 15 (1966).

Evidence relating to the other occurrences around Croyde and Saunton is also presented in those publications.

It's fair to say that in the 50 years since the publication of the "Glaciations of Wales" volume, there have been many other attempts to assess the origin and significance of the "till deposits".  Prof Clarence Kidson, in the 1977 volume on "The Quaternary History of the Irish Sea", in the context of a somewhat confused analysis, accepted that there is some till in North Devon, but agued that much of it was soliflucted and redistributed, and that most of the in situ till that remains dates from the Wolstonian glaciation.  Stephens, Synge, Mitchell and other also found difficulty in assigning the till to the last glaciation -- and they thought it was emplaced in the Riss /Saalian glaciation.  In their chapter on South-west England in the later volume called "The Glaciations of Wales and Adjacent Areas" (2005) Harrison and Keen accepted the presence of till at Fremington and elsewhere, and cited some (notoriously unreliable) amino acid dating on contained shell fragments in assigning an Anglian age to the glacial episode responsible.

The most detailed analysis of the Fremington, Croyde and Saunton deposits is in the GCR volume for SW England (1998), in which Croot and others suggest that some of the deposits interpreted as till may be something else, simply laid down in the vicinity of glacier ice. Their arguments are not very convincing, and seem to be driven by the desire to show that the South-West Peninsula was not actually glacieted!  At any rate, they suggest that any till that is present probably dates from the Anglian Glaciation, and not the Wolstonian / Riss / Saalian.  However, they provide no evidence other than saying "recent work suggests........".    So I think that conclusion can safely be ignored.

The modern geological map of the Fremington - Yelland - Bickington area, showing (in blue) the extent of the Fremington till and related deposits.

Conclusion

We can safely accept that there is genuine clay-rich till at Fremington and elsewhere.  However, because of a reluctance prior to 2000 to  accept that Late Devensian ice really was rather extensive in the Celtic Sea arena,  nearly all authors have assigned the till to the Wolstonian or the Anglian glaciation.  Some have gone through considerable intellectual contortions in the process. However, stratigraphically there is little justification for this, and above the till there really is not sufficient accumulated periglacial and colluvial material to justify any designation older than Devensian.  The Late Quaternary stratigraphy in North Devon has clear similarities with that of West Wales and Eastern Ireland, and if Late Devensian ice extended all the way out to the shelf edge, it could easily have reached the coasts of North Devon as well.

So I suggest that the Fremington till is Late Devensian, and I invite anybody who has evidence to suggest that this dating is incorrect to produce the goods for us to look at........