Fossil group

Cephalopods

Molluscs · Cambrian – Recent

The most advanced molluscs — active marine predators including ammonoids, nautiloids, belemnites and living squid, cuttlefish and octopus. Many built chambered shells for buoyancy, and the shelled forms are valuable index fossils.

A broad fossil group rather than a single taxon — the units below record it among their fauna or flora.