1.3" Crinoid (Agaricocrinus) & Gastropod (Platyceras) - Crawfordsville

This is a beautiful 1.3" long crinoid of the species Agaricocrinus americanus from the famous Crawfordsville, Indiana crinoid beds. The quality of preparation on this fossil is wonderful - using skillful air-abrasion techniques under a stereo microscope. There is a gastropod that's partially exposed from the calyx region of the crinoid. This gastropod is of the species Platyceras equilateralis.

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.

DETAILS
SPECIES
Agaricocrinus americanus & Platyceras equilateralis
LOCATION
Crawfordsville, Indiana
FORMATION
Edwardsville Formation
SIZE
1.3" long (including stem) on 1.9 x 1.7" rock
CATEGORY
SUB CATEGORY
ITEM
#122950
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