3.3" Crinoid (Agaricocrinus) and Sponge Fossil - Crawfordsville

This is a detailed Agaricocrinus americanus crinoid that naturally preserved in association with a sponge (3.1 x 2.8"). This specimen was collected from the famous crinoid beds near Crawfordsville, Indiana. The quality of preparation on this fossil is exquisite - using skillful air-abrasion techniques under a stereo microscope. There is some gap fill along a repaired crack between the sponge and the crinoid. The stem of the crinoid also appears to be a composite, meaning the crown of the crinoid and the stem are from separate crinoids.

It comes with an acrylic display stand.

Crinoids from the Ramp Creek Limestone were likely 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.


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DETAILS
SPECIES
Agaricocrinus americanus & Unidentified Sponge
LOCATION
Crawfordsville, Indiana
FORMATION
Edwardsville Formation
SIZE
3.3" long (stem included) on 5.5 x 4" rock
CATEGORY
SUB CATEGORY
ITEM
#122984
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