This is the “Fossil Friday” post #209.  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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For this week, we have the rarest of the Mazon Creek polychaete worms.  Palaeocampa anthrax described by Fielding Bradford Meek (1817-1876) and Amos Henry Worthen (1813-1888) in “Notice of some new types of organic remains from the Coal Measures of Illinois” in 1865.    Currently, it is thought to be related to a group of modern day annulid worms referred to as fireworms.  For more information, see Mazon Monday #187.

This concretion was collected from the Mazon River in August 2023.  It was opened via freeze/thaw, after cycling since January 2024.  The concretion was a bit ugly, with the shape suggesting a possible fern.

It did need a little repair, but not around the Palaeocampa.

A lucky split through the included fern, exposed the rare worm.