New to the Forum! Just a rookie looking for some help. This fossil was found just outside of Defiance, Ohio 70 yrs ago. The rock was found on the surface of a farm field, in an area not plowed. Rock is approx 8 inches in length, with its entire surface uniformly covered in bumps. Under magnification, very small crustacean type organisms can be seen embedded in the rock. At first, I thought it may be a stromatoporoid, but bumps on surface may not have enough of a conical shape....? Looking for advice on where in N.W. Ohio this could be taken for ID, if needed.