Northeastern Kentucky Museum

Orthoceras Fossils for Sale

Orthoceras are Nautiloids, primitive marine cephalopods that possess a shell.  They were most abundant during the Paleozoic Era-400 million years ago; today, only a single genus survives-the nautilus.  The shell is divided into a body chamber and many smaller chambers.  The chambered part of the shell is known as the phragmocone.  Nautiloids have heads with well-developed eyes, as well as grasping tentacles.  Orthoceras was an active swimmer, with the shell positioned horizontally in the water.  They swim by squirting water out of the body cavity. They scavenged and preyed on small animals.