Hi, @gillian-catlett – this is a horn coral! A solitary coral that was pretty common in the early Paleozoic.
Here is the classification information: Kingdom Animalia, Phylum Cnidaria, Class Anthozoa, Order Stauriida. I don’t know that I can identify it down to the species level but at least that’s some more info for…[Read more]

Hey @gillian-catlett ! This appears to be a crinoid stem segment or at least its external mold. Casey County has a number of formations which are of Mississippian age, so finding crinoids is not surprising.