A relatively large fossil cystoid is pictured here. It is probably a Caryocrinites persculptis which is found in the Waldron Shale of Clark County, Indiana, USA. The creature dates back to the Middle Silurian Period. One side of the fossil is coated with pyrite. It has not been cleaned yet and measures about 3 cm long. I used Weeks Trilobites web site for this identification with this web page. He has a stunning specimen with intact feeding arms and stem on this site shown at this link. WOW!
Illustrations are from Plate V (Figures 9-10) Indiana Department of Geology and Natural History Seventeenth Annual Report S.S. Gorby State Geologist 1891. The fossil shown is identified as a new species called Caryocrinus indianensis with figure 9 being described as azygous side view and figure 10 view of the summit. It was collected by J.F. Hammell in the Niagara Group in Jefferson County, Indiana.