Mystery Fossil Help ID

[jeramme]

Hey all, any ideas on what this might be?

 

[NJearthman]

Could be favosites a honeycomb coral. I think its a marine fossil because there appears to be a faint shell imprint on the backside.
If it’s non-marine it resembles tree bark of some Carboniferous plants.

 

[Older The Better]

Good call on the shell on the backside Bryozoan?

 

[Dakota Sioux]

That is a Hadrosaur skin impression fantastic and valuable