Macrocrinus Crinoid With Long Stem - Preserved Anal Tube

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. While most of the arms of the crinoid are either missing or buried in the matrix is displays a very well preserved anal tube coming out of the crown which is unusual. There is a nice section of stem still attached

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.