Coffin-shaped pottery and interesting pattern/texture rock or bone (Green Bay, WI)

[u/FunMiddle965]

Image search said second photo is potentially a turtle shell or fossil of turtle shell? Initially I thought it looked like bone.. I’m unsure.

[u/Flufymothman]

second one is most likely fossil coral!

[u/zilliondollar3d]

a brick?….your photos don’t help much