West Virginia Mississippian subperiod: marine to mudflats

[LoneRanger]

Took a day trip to Mississippian subperiod sites in West Virginia, with exposures that represent environments ranging from shallow marine to mudflats (reflecting periods of ocean transgression and regression).  Of course there were brachiopods; the one photo of a brach below shows pink/light red coloration, and I've also posted this in the General Discussion section under "Fossil Shells with Color Patterns."  I've never before found a brachiopod with shell coloration. 

 

There's also a photo of a sea pen (Pennatulacea, only right side is well exposed). 

 

And there is another photo of 2 matrix pieces with what may be tusk shells (scaphopods).  The bottom scaphopod (?) is 4.5 inches, while the top one is more fragmentary and is 1.75 inches.  If anyone has a different idea of what these are, please post your identification. 

 

Finally, as the ocean receded, mud flats appeared, and the final 2 photos show tracks of what are likely small crustaceans making their way across a long lost world.

 

 

[Mark Kmiecik]

Nice specimens. Thanks for sharing.

[Wrangellian]

Interesting stuff. I'm not sure but what you're calling a sea pen may be either a trace fossil or maybe a plant frond of some sort, thinly coated in mud. Fossil sea pens (or similar Ediacaran organisms) are very rare and I think it would be a significant find if that's what you have.

[LoneRanger]

The post above (by Wrangellian) made me rethink this ID of "sea pen," as I read that modern sea pens appeared in the Mesozoic and are likely unrelated to the Ediacaran organisms that have a similar appearance.  I believe this fossil is marine as it was found in the same area as brachiopods and other marine fossils.  So I'll have to rethink this ID.  As it's incomplete, it will probably be difficult to impossible to make a definitive ID.