Gastropod (Phylum Mollusca)

© Craven & Pendle Geological Society

Platyceras

Platyceras from the Coplow Limestone, Clitheroe, Lancs.

Class Gastropoda

This is one of the main divisions of the Phylum Mollusca.  Gastropods (snails and slugs) are elongate molluscs with a well-developed head and a large flattened foot and are believed to be the most abundant of all the molluscs stretching from the Cambrian to present day.  They are characterised by having a coiled calcareous univalved shell.

Platyceras is found usually in a naticiform to uncoiled state; often irregular, coiling.  Growth lines and corrugations dominate the ornament.  This particular gastropod had an interesting co-existence with the crinoids.  Often described as symbiotic, Platyceras was thought to have attached and scavenged directly off the crinoid calyx perhaps feeding off ejected material from the anal tube.