Rookie needs help with ID-found in illinois.

[Thefossildude]

Found in illinois near a river. Any ideas?

[crinoid1]

This could be a few things: a brachiopod, part of a horn coral, or possibly some other invertebrate. It's a shame this little guy isn't more complete, as I could be a little more confident in an ID! Whatever it is, it does look neat. I lean most towards brachiopod. 

[Raggedy Man]

Some general information about the location you found it would help...like, county...river name. It could come from natural erosion from a rock face or erratic glacial deposition. Thanks

 

Best regards,

Paul

[Rockwood]

I would also lean toward brachiopod. I find relatively coarse ridged shells of them that are crushed and distorted as this appears to be.

This would be a piece of the internal mold. The ridges would likely be to some extent an overprinted external feature.

[abyssunder]

Welcome to the Forum !
I see it as a sedimentary rock with a shell imprint on one side.

[ashcraft]

Probably a chert nodule with a brachiopod imprint.  Probably Paleozoic era.  Possibly wash out of the Appalahian mountains, but could be from material out of Michigan, 
Wisconsin, Minnesota area.

[fifbrindacier]

I vote for @abyssunder's opinion.