This crinoid appears to be a Zeacrinites wortheni (Hall, 1858) crinoid calyx fossil. As a bonus, this calyx has part of its stem. It was found in the Glen Dean Member of Grayson County, Kentucky, USA. The fossilized animal dates to Chesterian, Upper Mississippian Period. I believe this species was named for a paleontologist from Illinois named Amos Henry Worthen (1813-1888). Worthern was James Hall's assistant while he was State Geologists of Iowa 1855-1857.
Next to the calyx is some intricate Fenestella bryozoan fossils.
Thanks to Kenny for this remarkable fossil gift.
