Found in Mississippian area of geodes in Indiana

[traveltip1]

I found this 1+ inch wide item in a stream in the Mississippian strata in Indiana. There are many geodes and crinoid columnals in this area.

What is it?

[ClearLake]

Looks like a geode to me, crack it open (or saw it open) and see what you have.  I don't recognize any crinoidal symmetry.