Pennsylvanian, Desmoinesian
Francis Creek Shale, Pit. 11
Braidwood, IL, USA
Very distinct 1.6 inch millipede
Insect, Mazon Creek. Carboniferous.

Millipedes occur sporadically in the fossil record.  The earliest forms may date back to the Ordovician based on trace fossils but the earliest body fossils are known from the Late Silurian.  While at least six genera have been documented from the Mazon Creek area so far. millipedes make up only about one-tenth of 1% of fossil finds there (Braidwood Fauna).