7" Crinoid (Actinocrinites) With Long Stem - Crawfordsville

 
 
This is a very impressive 7" long Actinocrinites gibsoni from the famous Crawfordsville, Indiana crinoid beds. The quality of preparation on this fossil is exquisite - using skillful air-abrasion techniques under a stereo microscope. The crown of the crinoid is 3.3" long, very detailed and 3D. The stem of the crinoid is quite long, but the crinoid is a composite meaning the stem and crown are not from the same crinoid. There is a second, smaller crinoid at the top of the largest crinoid. This smaller crinoid is of the species Platycrinites brevinodus and measures 1.5" long. The solid limestone slab measures 10.2x5.7" and comes with a display stand.

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
Actinocrinites gibsoni & Platycrinites brevinodus
LOCATION
Crawfordsville, Indiana
FORMATION
Edwardsville Formation
SIZE
3.3" long crown. 7" including stem
CATEGORY
SUB CATEGORY
ITEM
#122941
GUARANTEE
We guarantee the authenticity of all of our
specimens. Read more about our
Authenticity Guarantee.