Discussion

Abstract

Dr. J. D. Solomon said that when he had discovered Scandinavian minerals in the Covehithe clay, which seemed to be continuous with that at Easton Bavents, he had naturally correlated it with the Norwich Brickearth, which occurred at a similar level in the cliffs a little way to the north. Dr. West’s hypothesis, which involved an earlier incursion of Scandinavian ice, was rather uneconomical, and he hoped that it could be checked by a mineralogical investigation of the ‘Baventian’ clay from the Ludham borehole. As the sands and gravels above the Easton Bavents clay were accepted as belonging to the Westleton-Mid-Glacial complex, there must be a gap in the succession corresponding to the Weybourne Crag-Forest Bed period, and it might be that the discontinuity occurred below the clay rather than above it. Dr. T. Barnard said that the authors had established their ecological correlation based on species of benthonic Foraminifera. Dr. West in his delivery of the paper had not mentioned planktonic Foraminifera; their absence might indicate a cold south-flowing current, diverting these Foraminifera south-eastwards into the Netherlands. Foraminifera down to 250μ were recorded on the authors’ occurrence-chart, and it appeared likely that the planktonic Foraminifera, usually much smaller than this, had been missed. The recent work of Phleger, Parker, and others had proved the importance of planktonic Foraminifera as climatic indicators. No mention was made of the occurrence of ostracods, another important group, which often gave better results as climatic indicators than benthonic Foraminifera confined to inshore areas.