Bottom of an Eucalyptocrinus elrodi (Miller, 1891) crinoid calyx with a partial covering of pyrite crystals. Found in the Waldron Shale of Clark County, Indiana. This crinoid existed in the Middle Silurian Period.
See a prepared E. elrodi found in St. Paul, Indiana at Crinus's fossil web site.
See more examples of this species at the Weeks Trilobite site.
This particular species is not quite as common as the Eucalyptocrinus crassus which is an index fossil for this formation.
See the Weeks Trilobite web site for more examples of the Eucalyptocrinites crassus.
Crinus fossil web site also has an E. crassus pictured found in Sellersburg, Indiana as well as a holdfast found in Waldron, Indiana.
This fossil was sandblasted -- thanks Kenny!