Chalk Group Lithostratigraphy: East Anglia - Lower Inoceramus Bed

The Lower Inoceramus Bed equates with the 1st Inoceramus Bed of Jeans' (1973) description of the Chalk of northern England. It occurs widely across East Anglia, from Sudbury (Pattison et al., 1993) in the south to Hunstanton (Gallois, 1994) in the north. It comprises grey, coarse, shell-rich chalk, with abundant fragments of the bivalve Inoceramus, overlying a sharply defined basal erosion surface, locally with common glauconitised and phosphatised chalkstone pebbles (Gallois, 1994). In north Norfolk the bed is c. 0.5 m thick, c. 2-3 m thick in the Ely district (Gallois, 1988) and c 1 m thick in the Clare Borehole [TL 7834 4536], near Sudbury (Pattison et al., 1993). The dominant fossil is Inoceramus crippsi, but locally there is a rich fauna that also includes brachiopods, ammonites and echinoids (Gallois, 1994)

Macrofossil Biozonation: M. mantelli Zone, S. schlueteri Subzone

Correlation: see Correlation with other UK Chalk Group successions

References

BRISTOW C R. 1990. Geology of the country around Bury St. Edmunds. Memoir of the British Geological Survey.

GALLOIS, R W.1988. Geology of the country around Ely. Br. Geol. Surv. Memoir.

GALLOIS, R W.1994. Geology of the country around King's Lynn and The Wash. Memoir of the British Geological Survey.

JEANS, C V. 1973. The Market Weighton structure: tectonics, sedimentation and diagenesis during the Cretaceous. Proceedings of the Yorkshire Geological Society, Vol. 39, 409-44

PATTISON, J., BERRIDGE, N. G., ALLSOP, J. M. & WILKINSON, I. P. 1993. Geology of the country around Sudbury (Suffolk). Memoir of the British Geological Survey, Sheet 206 (England & Wales).