Discusses the nomenclature of the cardioceratids from a clay pit in the upper Oxford clay at Purton, Wiltshire, and other clay pits in the region, and explains the zonal sequence and terminology of the lower Oxfordian (Jurassic), which comprises the Cordatum, Mariae, and Lamberti zones. A revised correlation table of the lower Oxfordian at English localities is given.

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