The fossil pictured appears to be a Pterotocrinus depressus (Lyon and Casseday, 1860) crinoid calyx. It was found in the Glen Dean Formation of Grayson County, Kentucky, USA. The fossil is about 2 cm wide. This animal dates to Chesterian, Upper Mississippian Period.
Thanks to Kenny for the image.
See more images of crinoids like this at Don R. Chesnut's web page on fossils of the Sloans Valley Member (Paragon Formation).
