Crinoid (Eucalyptocrinus) Holdfast With Brachiopods

This is a 2.4" wide crinoid holdfast from the Waldron Shale of Indiana. Holdfasts are what would have anchored the crinoid to the bottom of the ocean. It has been cleaned under microscope using air abrasives. There are several brachiopod fossils and other crinoid parts present on the rock.

Crinoids are commonly known as sea lilies, though they are animals, not plants. They are echinoderms related to starfish, sea urchins, and brittle stars. They attached themselves to the sea floor and had feathery, tentacle-like appendages which they used to capture particles of food. First appearing in the Ordovician period, 488 million years ago, they still survive to this day in deep water.