Two Beautifully Preserved Macrocrinus Crinoids - Indiana

This is a beautiful plate with a pair of nicely preserved Macrocrinus mundulus crinoids 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. The anal tube of one of the cinoids is still preserved, protruding from the crown.

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.