The palaeogeography of the London Clay Sea

Abstract

The London Clay of England (London and Hampshire Basins), Denmark, Germany, Holland and Belgium is briefly described, and the question of its correlation with the Paris Basin Lower Eocene summarised. The fauna and flora of the formation are reviewed as evidence of conditions at the time of its formation. The London Clay Sea is considered to have transgressed from a region of continuous Palaeocene-Lower Eocene sedimentation in the Danish-NW. German area, where it opened north-westwards, over Holland, Belgium and much of the London Basin, then to have transgressed farther over the Hampshire Basin to a Tethyan connection over the English Channel, finally to have retreated eastwards over S. England. The famous tropical flora is considered to have grown on the south-western coasts. The London Basin lower clays are probably represented by Reading Beds in the Hampshire Basin, and the English and Belgian London Clay by non-marine Sparnacian in the Paris Basin. It is recommended that a division into Palaeocene and Lower Eocene is adequate for the pre-Lutetian tertiaries of north-western Europe, instead of stage-names now in use; formation-names are unaffected. It is considered that palynology may yield more reliable datum-lines with these deposits than either facies-faunas or diachronous transgression-planes.