.5" Pyritize Goniatite (Tornoceras) - Hungry Hollow, Ontario
This is a pyrite replaced goniatite (Tornoceras) fossil in a blob of pyrite from the Widder Formation in Arkona, Ontario. There is also an upside down trilobite head and brachiopod in the limestone.
Goniatites possessed a shell which was 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, being free swimming and possessing a head with two well developed eyes and arms.