Detailed Macrocrinus Crinoid Fossil - Indiana

This is a very detailed 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. The crown of this specimen is 1.2" long on a 2.3x2.2" piece of limestone.

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.