This was found in a field (sandy loam) about 50 years ago 2 miles northwest of Girard, Georgia. It is extremely hard appears to be some sort of metamorphic rock or coprolite perhaps?? (not man made concrete as some have suggested) with varying shades of brown to reddish brown and exhibits unusual cracking and weathering. It measures 18'' in length and weighs about 50-60 pounds and also has indentation in the middle. Any ideas on what it might be?