Illinois is home to a fossil site called Mazon Creek, which contains plant and animal fossils, as well as hard and soft tissue preservation. Fossils from the Mazon Creek area are found in the Francis Creek Shale in the Braidwood – Coal City area of Illinois. First discovered in the mid-1800s during coal mining operations, these plant and animal fossils provide a unique look into biodiversity from the Pennsylvanian, 307 million years ago. The Chicago Academy of Sciences' collection of Mazon Creek area fossils includes this holotype of Protodictyon pulchripenne, a winged insect. A holotype is the specimen used to describe a species.
Holotype from Mazon Creek