Summary

The geology and palaeobotany of the Pleistocene deposits in the Nar Valley, Norfolk, have been investigated. A low till is overlain by interglacial sediments consisting of lacustrine beds underlying an estuarine clay. These are covered by an upper till and glacial gravel.

The pollen analysis of the lacustrine sediments shows an early phase of park-tundra and then, due to an amelioration in the climate, the expansion of the mixed oak forest suggesting that the climate was at least as warm as at the present day. The pollen in the estuarine clay traces the decline of this forest and the increase in coniferous trees, indicating that the marine transgression took place after the climatic optimum.

The tills are defined and correlated with others in East Anglia by a comparison of the texture, erratics and the preferred orientation of the stones. The Jurassic erratics and the westerly preferred orientation of the stones indicate that the lower till was deposited during the Lowestoft Advance, while the upper till has a N.-S. preferred orientation comparable to the Gipping Advance.

This correlation of the tills indicates that the Nar Valley interglacial sediments are in a stratigraphical position similar to that of the Hoxne interglacial beds. The similarities between the vegetational successions of these two deposits is further evidence that the Nar Valley interglacial beds are of Great (Hoxnian, Elster/Saale) Interglacial age.

Both the pollen diagrams and the marine faunas of the Nar Valley and Clacton estuarine clays are very similar. These deposits, however, occur at different heights above sea level, and this is attributed to some relative vertical movement since their deposition.