Mystery Piece Found Along With Edestus Teeth Illinois Coal Mine Carboniferous

[Kurufossils]

Hi all, this strange piece came with a batch of edestus fossils that were found in a coal mine in Illinois. Have no idea what it could be, the front seems to be coated in black coal mostly while the back has what appears to be ridges. All I know about the location is it was found in a coal mine along with some edestus teeth that is Carboniferous in age. Hoping with some help to get to the bottom of this mystery.

[Rockwood]

Artesia. I think.

[Kurufossils]

I think plant is a good guess it looks similar.