Pennsylvanian

Francis Creek Shale

Pit 11, Will Co., IL, USA

12mm isopod in 20mm paired concretion

Isopod, Mazon Creek

Isopods belong to a group of crustaceans that inhabits today’s marine, freshwater, and land environments.  They are uncommon in the Mazon Creek deposit, one of the earliest occurrences in their history.