What is this rock?

[Animamundi]

Hello! I found this rock in Cooperstown, New York. It doesn't worth anything probably but I am curious what kind of rock it is? It looks like a snake skin/ reptile skin. I found something on Google about the snakeskin agate but my stone doesn't look really like that. Thank you!

 

[Back-of-the-boat]

Maybe Iron-oxide concretion, Google that.

 

[Sod Buster]

The images are a bit blurry when enlarged. Google Petoskey stone images and see what you think.

 

[NJearthman]

Looks like Favosites an extinct coral. Google it and check images. Also this Favosites? - Fossil ID - The Fossil Forum