I did not find this specimen, i purchased it from a plant/book store in a small town east of Traverse City, Michigan. I was able to confirm the store owner collected this specimen in Michigan near Charlevoix. It was broken from a larger stone, exposing intricate features of the coral as small as 0.005", preserved for about 400 million years.
This specimen is Hexagonaria percarinata, also known as a Petoskey stone, and Michigan's state stone since 1965 3 . The corallites, tabulae, Septa, and tabularium are exceptionally well preserved.