Basically, it is fossilized coral that - for what we know - dates back to about 350 million years ago. The Petoskey Stone is known to develop in warm seas near the equator (since it is coral it forms in seas). This fits the location is close to the equator. Since this moved, it shows the power of Plate Tectonics. Plate Tectonics is related to the Theory of the Continental Drift.
