"Lichenocrinus tuberculatus"   scale in cms CLASS - Crinoidea ORDER - Disparida FAMILY - GENUS/SPECIES - "Lichenocrinus tuberculatus" ROCK UNIT - Whitewater Formation AGE - Ordovician Period (about 450 million years old) LOCALITY - Clarksville, Clinton Co., Ohio, USA This "species" is just a name for part of an unknown crinoid. The fossil represents a holdfast, or anchoring device. There were were many ways that crinoids anchored themselves to the sea floor. This holdfast is a disc which cemented the stem to a hard surface, such as a large shell or a rock-like sea floor. Note the circle in the center of these holdfasts mark where the crinoid stem attached. PRI 42167