How to Identify Cephalopod Fossils

Identify where the fossil was found. Cephalopods live in oceans, so if the fossil's location is near an ocean or where an ocean once was, your fossil could be that of a cephalopod.

Identify the era and shape of your specimen. Cephalopods of the Cambrian era had cone-shaped shells. The outer shell became more spiral with evolution and gained a shape similar to that of a snail shell. Cephalopods with this kind of fossil structure are known as nautiloidea. Ammonoidea, which have coiled shell structures, lived from the Devonian to the Cretaceous era. Unlike nautilodea fossils, ammonoidea have a strictly spiral coil and siphuncles within the chambers of the shell. Coleoidea fossils, from the Cambrian era, are usually flat shells.

Look for any signs of soft body features. Sometimes you will see imprints of tentacles or suckers on a fossil that will help you identify the type of cephalopod.