Friday, August 3, 2012

Petoskey Stone and more

For today's posting I have a couple of photos I took while driving back from Minnesota.

I was asked by my book distributor, Partners Books, who also publishes books to send them pictures of Petoskey Stones. This inspired me to do a blog update on Michigan's state stone.

A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized coral, Hexagonaria percarinata. The Petoskey Stone is a coral that lived 350 million years ago during the Devonian age when the northern part of Michigan was covered with a sea of warm water. The stones were freed from their sedimentary matrix when glacial ice plucked stones from the bedrock, grinding off their rough edges and depositing them in northern lower Michigan's upper peninsula. In some areas of Michigan, complete fossilized coral colony heads can be found.

The soft living tissue of the corallite was called polyp. At the center of the polyp was the food intake opening or mouth. This dark spot, or the eye of the corallite, has been filled with silt or mud that petrified after falling into the openings. Surrounding the opening were tentacles that were used for gathering food and drawing the food into the mouth. This living corallite thrived on plankton which lived in the warm sea.  Calcite, silica and other minerals have replaced the original elements in each cell. Each chamber or corallite at one time was a living marine animal that grew in colonies. The Petoskey stone is also known as a colony coral.

Petoskey stones are found in the Gravel Point Formation of the Traverse Group. When dry, the stone resembles ordinary limestone but when wet or polished using lapidary techniques, the distinctive mottled pattern of the six-sided coral fossils emerges. It is sometimes made into decorative objects. Other forms of fossilized coral are also found in the same location.

The name comes from an Ottawa Indian Chief, Chief Pet-o-Sega. The city of  Petoskey, MI is also named after him, and is the center of the area where the stones are found.  According to legend, Petosegay was the child of a descendant of French nobleman and fur trader, Antoine Carre and an Ottawa princess. Petosegay, meaning "rising sun", "rays of dawn" or "sunbeams of promise", was named after the rays of sun that fell upon his newborn face. In keeping with his promising name, Petosegay was a wealthy fur trader who gained much land and acclaim for himself and his tribe. He was remarked upon to have a striking and appealing appearance, and spoke 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 passing, a city began on his land along Little Traverse Bay. The settlers christened the newborn city Petoskey, an anglicized form of Petosegay.
In 1965, it was named the state stone of Michigan.

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