Lampshells may have been the most abundant animals, with numerous different species, living in and around the Silurian reefs. Kirkidium had a large, heavy shell and lived in places where the currents and waves were strong.

A lampshell’s body is mostly enclosed in a bivalve shell like that of a modern clam or scallop, but the animal has a completely different appearance. Most lamp shells have a short foot (pedicle) that sticks out between the valves at the back and anchors the creature to the sea bed. Between the two valves is a coiled arm-like structure bearing many small tentacles. The arm pumps water into the shell and filters out plankton.