Three Species of Crinoids on One Plate - Crawfordsville, Indiana

These are three fossil crinoids from the Edwardsville Formation crinoid beds near Crawfordsville, Indiana. This association includes a Cyathocrinites multibrachiatus crinoid (#17), an Agaricocrinus americanus crinoid (#54) and a Onychocrinus ulrichi crinoid (#81).

These fossils were prepared using skillful air-abrasion techniques under a stereo microscope. This rock broke into several pieces during collection, requiring crack repair and gap fill restoration in spots. The rock has been stabilized across the entire backside. Comes with an acrylic display stand.

#17 - Cyathocrinites multibrachiatus (2.1" long including stem)
#54 - Agaricocrinus americanus (2.1" long including stem)
#81 - Onychocrinus ulrichi (1.75" wide )

It is believed that crinoids from the Ramp Creek Limestone were buried in sediment from nearby deltas during storms. The resulting siltstone deposits are soft enough that fossils can be extracted in exquisite, three-dimensional relief.

Crinoids, sometimes commonly referred to as sea lilies, are animals, not plants. They are echinoderms related to starfish, sea urchins, and brittle stars. Many crinoid traits are like other members of their phylum. Such traits include tube feet, radial symmetry, a water vascular system, and appendages in multiples of five (pentameral). They first appeared in the Ordovician (488 million years ago) and some species are still alive today.

Cyathocrinites multibrachiatus, Agaricocrinus americanus & Onychocrinus ulrichi
Crawfordsville, Indiana
Edwardsville Formation
5.2 x 3.1" rock
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