The pliocene-pleistocene boundary in the east of England

Abstract

At the XVIIIth Session of the International Geological Congress in 1948, a Commission was appointed to advise on the definition of the Pliocene-Pleistocene boundary. The changes in the classification of the Pliocene deposits of the East of England that would be necessitated, if the Commission's recommendation is adopted, are now reviewed. It appears that two courses are feasible: (a) to draw the boundary at the unconformable base of the Red Crag, or (b) to regard the Red Crag as Plio-Pleistocene and abandon the attempt to locate an imaginary boundary within this continuous series of deposits, the Mollusca of which yield evidence of progressive climatic deterioration. The former course is considered preferable on the ground of “ease of application”. In particular, it is noted that the placing of the boundary, as has been suggested, between the middle and upper divisions of the Red Crag (assuming that these divisions could be precisely delimited) would leave beds containing remains of horse and elephant in the Pliocene, which would be contrary to the Commission's intentions.