This is the "Fossil Friday" post #7. 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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Today's fossils for Fossil Friday are brachiopods from the Silica Shale in Ohio. The Silica Shale dates to the Middle Devonian Period about 390 million years ago. During the Devonian, North America occupied a much more southern position on Earth than today. This rock formation is part of the Michigan Basin, which was slowly subsiding during this time. Meanwhile, to the east the Acadian Mountains were being formed as part of the Acadian Orogeny. Pulses of fine sediment were laid down in the Michigan Basin to help create the beautiful fossils found around Toledo, Ohio.
Portion of global paleogeographic reconstruction of the Earth in the middle Devonian period 385 million years ago, showing Eastern North America with key features labeled - http://jan.ucc.nau.edu/rcb7/namD385.jp
Here are a couple sites (here and here) that can help you identify fossils of the Silica Shale. The LaFarge quarry in Paulding, OH is a famous locality where anyone can collect from the Silica Shale. Details can be found here.
Most of these brachiopods are partially or even fully pyrtized. It makes them heavier and quite beautiful.
Mucrospirifer mucronatus
Stropheodonta demissa
Mediospirifer audaculus
Paraspirifer bownocki
Pseudoatrype devoniana
