Did you know Illinois has a state fossil? It does. And no, it’s not Don Hickman.
It’s the Tully Monster:
The Tully Monster (Tullimonstrum gregarium), so far apparently unique to Illinois, was a soft-bodied invertebrate that lived in shallow tropical coastal waters of muddy estuaries during the Pennsylvanian geological period, about 300 million years ago. The Tully Monster had fins not unlike a cuttlefish and a long proboscis with eight small sharp teeth with which it may have probed actively for small creatures and edible detritus in the muddy bottom. It was part of the ecological community represented in the unusually rich group of soft-bodied organisms represented among the assemblage called the Mazon Creek fossils from their site in Grundy County, Illinois.Tully the Monster became the state fossil in 1989.