Essexella asherae
Pennsylvanian
Francis Creek Shale
Pit 11, Will Co.
Illinois, USA.

Exceptional fossil specimen of Essexella asherae from the famous Francis Creek Shale of the Mazon Creek fossil beds, Pit 11, Will County, Illinois. Dating to the Pennsylvanian Subperiod approximately 307 million years ago, this rare soft-bodied fossil preserves one of the most iconic organisms from the classic Mazon Creek fauna.
Big 75mm in 75mm paired concretion