1.9" Carboniferous Fossil Goniatite (Muensteroceras) - Indiana

Carboniferous Fossil Goniatite (Muensteroceras) - Indiana #162623

This is 1.9" wide fossil goniatite (Muensteroceras parallelum) from the Rockford Limestone of Jackson County, Indiana. The outer shell is gone leaving the intricate patterns of the inner shell sutures. This specimen is from an old collection.

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.