Gastropods
Gastropods are snails. The gastropods found in the Cretaceous formations of Mississippi are marine. In most cases (locally), groundwater has leached the original calcite shells over time, leaving only the steinkern/mold (where mud has filled in the voids of the shell, preserving its shape). Sometimes, the animal can be identified by its steinkern, but I will not attempt to do so unless a professional has supplied the ID.
Bivalves
Brachiopods
Tusk shell
Annelid worms
CRETACEOUS MISSISSIPPI 