Where is the GBG limit in SW England?

As my faithful fellow-bloggers know, I have spent a lot of time on this blog trying to work out where the GBG limit may be in SW England.  (Are we talking here about one big glaciation?  Or maybe we are talking about several glacial episodes, spread over hundreds of thousands of years, and reaching different parts of the Bristol Channel coastline at different times?)

This has all come into focus again because my dear friend MPP has repeated what my other dear friend GW has said several times on the record -- namely that glacier ice has never affected the coasts of Devon, Cornwall, Somerset and the SW generally.

Interestingly enough, academic geomorphologists, whom we would expect to know about these things, have chosen by and large to stay well clear of the discussion, for reasons that I find hard to understand.  (Are they actually SCARED of Profs GW and MPP?  That would surprise me, since they both seem to me to be perfect gentlemen.)  But if you press them, of course they know that the ice DID reach these coasts on the shores of the Bristol Channel.  It's just that they don't want to say so, for fear of being knee-capped or something. 

In exchanging messages with various colleagues whom I respect, I got this reply from one of them.  He says there are "..........very clear signs of glaciation further north at Kenn in what was Avon and in the Bristol-Bath area.  There are some amazing landforms such as the Court Hill col-gully, infilled with fluvioglacials, including enormous boulders until they put the M5 through.  Some of the infill deposits are still visible in the wood beside the motorway.  At Kenn, till-like material, which includes striated boulders weighing several tons, is overlaid by marine and non-marine interglacial deposits. Amongst the erratics recovered were a piece of Ulster White Limestone, which contained the usual characteristic foraminiferal fauna of this unit. See the many papers of Dave Gilbertson's work in the area, and his PhD thesis, summarised and updated in the GCR volume.   Aminostratigraphy suggests several ages for the interglacial deposits - some are as old as OIS 15 (although there should be a considerable health warning on all these very old aminostratigraphic 'dates', as Kirsty Penkman has demonstrated!)  I spent some time working on the issue of glaciation in this area, with follow-up investigation in the Kenn area, in Gordano and in the Bath/Bristol Avon valley.  There is no doubt in my mind about a glacial incursion in that area, as far upstream as Bathampton, but no further. There are plenty of erratics recycled in the river gravels at Bathampton and elsewhere through the valley, mostly derived from the Bristol District and/or the S Wales coalfield, but I never saw any bluestone fragments, in any of my pebble counts."

I won't mention his name, for fear that medics in white coats or heavies in dark coats will come calling on him, but that sounds pretty unequivocal to me.   He also says:  "My work with erratic palynomorphs suggests that the ice sheet that was responsible for the deposition of the Fremington Clays was coming pretty well southeastwards and the ice coming onshore at Fremington would probably have 'missed' Pembrokeshire".

I think I'm right in saying that everybody who knows anything about glacial deposits accepts that we have a true glacial till at Fremington, and more till on Lundy Island, and more till on the north coasts of the Scilly Isles.  There is a lot of debate about other deposits, like the Trebetherick Boulder Bed, but that's enough evidence to be going on with, and if we have a number of sites where glacial deposits are widely accepted (Kenn, Court Hill, Nightingale valley, Bathampton, Lundy, Fremington, and the Scillies, to name just some) then only an idiot would say that the ice did not cross the Bristol Channel.

But the idiots keep on saying it, and those who should put them right just keep on saying nothing.  This is a very strange and even bizarre sociological and psychological phenomenon, and even a hoary old ex-academic like me (having seen most things in my time) finds that very strange.  This is actually nothing to do with academic etiquette.  That requires the experts in a particular field to assess the evidence and speak out, and the non-experts to keep quiet or to defer to the experts.  But here we have the non-experts pontificating and the experts shrinking away into the undergrowth on the grounds that they "don't know enough about the subject."  Oh my God.....  whatever happened to academic integrity?