Hexagonaria percarinatum

Cut and polished coral.

Hexagonary He lived during the Devonian period in the areas we now know as the American Midwest, as well as in some places in Canada, England, Germany and Asia. The species that produces Petoskey stones It lived during the Middle Devonian and is found only in the Gravel Point Formation of Michigan. During the last ice age, the glaciers that created the Great Lakes excavated fossils from H. percarinatum into the bedrock and deposited them on the lake shore around the Lower Peninsula of Michigan. Erosion from glaciers and lake water wore the rocks down to the rounded shapes that Petoskey stones present today.