This is “Fossil Friday” post #121.  Expect this to be a somewhat regular feature of the website.  We will post any fossil pictures you send in to esconi.info@gmail.com.  Please include a short description or story.  Check the #FossilFriday Twitter hash tag for contributions from around the world!

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This week’s Fossil Friday post is an Alethopteris serlii from the ESCONI Danville spoil pile field trips.  That spoil pile dates to the early 1900’s.  The Dering Coal Company opened the mine to exploit the Herrin No. 6 coal.  The shale in the spoil pile consists of mostly Energy Shale, which is about 2.5 million years younger than the St. Francis Shale of Mazon Creek.  More information about the Energy Shale and the Herrin Coal can be found in Mazon Monday #86. 

This specimen was in a concretion, which was collected in the Spring 2022 field trip.