.95" Fossil Goniatite (Anthracoceras) - Bear Gulch Limestone, Montana

Goniatites possessed a shell divided internally into chambers filled with gas for buoyancy. An open chamber at the front of the shell provided living space for the animal. The general morphology and habit of goniatites was probably similar to that of their later relatives the ammonites: they swam freely and possessed heads with two well developed eyes and arms.