I found this about 10 years ago while hunting crinoids in a river near Crawfordsville IN. I believe it to be from the Edwardsville formation which is late Mississippian. This spot is famous for it's wonderfully preserved and complete crinoids, but i don't think my mystery fossil has anything to do with them.
The backside of the fossil is encrusted with crinoid stem fragments (as expected), so i know the age should be correct as most crinoids found there (late Mississippian). Now it looks to me like a part of a crab carpace, but the only crab material that i have found is macro and micro pieces. The mystery piece is about 2 1/4" x 2".
Have there been crabs found in Crawfordsville? If not crab, what???
Any and all ideas are welcomed and appreciated! Hopefully i can finally put this mystery to rest.
"Bottom/backside"
Thanks for looking!