2.25" Macrocrinus Crinoid - Indiana

This is a very detailed, 3D Macrocrinus mundulus crinoid from the famous Witherspoon crinoid quarry near Crawfordsville, Indiana. The quality of preparation on this fossil is exquisite - using skillful air-abrasion techniques under a stereo microscope. There is a stem section from a very large crinoid on the rock next to it.

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.