?Jurassic and Cretaceous macrofossils from Sheet 266 (Marlborough) : autumn 2011

Macrofossils from surface and outcrop exposures of the Chalk Group on Sheet 266 (Marlborough) were collected in November 2011 in connection with the resurvey of that district. The material ranges from the Mantelliceras mantelli Zone to the Micraster coranguinum Zone, and can be assigned to the West Melbury Marly Chalk, Zig Zag Chalk, Holywell Nodular Chalk, Lewes Nodular Chalk and Seaford Chalk formations. At localities exposing the basal Seaford Chalk Formation, the lithology is unusually hard, nodular and sponge-rich, and more closely resembles typical Lewes Nodular Chalk Formation. A field brash collection of large, thick-shelled oysters showing evidence of reworking, located near the base of the Gault, appear most likely to have been derived from the Lower Cretaceous or Jurassic.