Macrocrinus & Actinocrinites Crinoid Association

This is an interesting association of two types of crinoids from the famous Witherspoon crinoid quarry near Crawfordsville, Indiana. The crinoid with the stem attached is a well preserved Macrocrinus mundulus and the second crinoid crown is Actinocrinites gibsoni. The Macrocrinus is 4.4" long including the stem and both crinoids display very aesthetically on a 4.8x4.4" section of limestone. The quality of preparation on this fossil is exquisite - using skillful air-abrasion techniques under a stereo microscope.

It is believed that crinoids from the Edwardsville Formation 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.