Agaricocrinus & Macrocrinus Crinoids - Indiana

This is a nice association of two different types of crinoids from the famous fossil beds at Crawfordsville, Indiana. There is nicely preserved Agaricocrinus americanus (larger crinoid) along with a small Macrocrinus mundulus. Both specimens are nicely detailed and have been prepared under microscope using air abrasives.

Please note that the Macrocrinus was probably composited onto the plate.

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.