This is the "Fossil Friday" post #28. Expect this to be a somewhat regular feature of the website. We will post any fossil pictures you send in to [email protected]. Please include a short description or story. Check the #FossilFriday Twitter hash tag for contributions from around the world!
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For Fossil Friday this week, we are going to highlight Petosky Stones, which are found around the towns of Petosky and Traverse City along Lake Michigan in the state of Michigan. They were named the state stone of Michigan in 1965. The stones are actually a fossilized rugose coral, Hexagonaria percarinata, which lived during the Devonian Period about 350 million years ago. They went extinct at the end of the Permian as part of that mass extinction event. Rugose corals could be solitary or colonial. Hexagonaria was colonial. That's why we find fossilized chunks with interlocking hexagonal shapes. These shapes are very distinctive when smoothed and polished. The genus Hexagonaria was pretty common and fossils can be found across the mid-west. Besides Michigan, they are very common around Coralville, Iowa.
The name comes from an Ottawa chief, Chief Pet-O-Sega, who was the son of a French fur trader and an Ottawa mother. The city of Petosky is also named after him. From Wikipedia.
According to legend, Petosegay was a descendant of French nobleman and fur trader, Antoine Carre and an Ottawa daughter of a chief. Petosegay, meaning "rising sun", "rays of dawn" or "sunbeams of promise", was named by his father after the rays of sun that fell upon his newborn face. Building on his father's start and his place among the Ottawa, Petosegay became a wealthy fur trader who also acquired much land in the region, gaining acclaim for himself and his band. He was said to have a striking and appealing appearance, and spoke both French and English very well. He married another Ottawa, and together they had two daughters and eight sons. In the summer of 1873, a few years before the chief's death, settlers began to develop a village on his land along Little Traverse Bay. The settlers named it Petoskey, an anglicized form of Petosegay.[2]
Michigan.org has a good page with tips on where to find the stones. You can also find information on geologyin.com. Maybe, plan a vacation to collect them next summer...
