This is a fossil hash of Crinoids embedded in limestone matrix. It is from the Silurian Period (approx. 420 million years ago). The specimen has countless Crinoids and Crinoid fragments in it.
Locality : Brassfield Formation, Oakes Quarry Park, Dayton Ohio (USA).
Refer to the photos. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown. It weighs 74 grams. Your purchase will include an ID label.