Macrocrinus Crinoid With Preserved Anal Tube - Indiana

This is a 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 nice section of stem attached and the anal tube is also well preserved. The entire crinoid is 4.1" in length.

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.