gallery below will contain a mere sampling of more than 400
flora and 300 fauna that have been identified in the Mazon
Creek assemblage. The astonishing diversity includes cnidarians,
echinoderms, worms, snails, clams, shrimps, eurypterids, fish,
hexapoda (including insects, millipedes, centipedes), arachnids
(scorpions and spiders) amphibians, and horseshoe.
Mazon Creek fossils are conservation
lagerstätten found near Morris, in Grundy County,
Illinois. The fossils are found in ironstone concretions,
formed approximately 300 mya in the mid-Pennsylvanian Epoch
of the Carboniferous
Period of the Paleozoic. These concretions frequently
preserve both hard and soft tissues of faunal and floral life,
including many soft-bodied
organisms that rarely fossilize.
majority of the Mazon Creek collecting areas are the spoil
heaps of abandoned coal mines, and the most famous of these
is Peabody Coal Pit 11. Pit 11 now serves as a cooling pond
for the Braidwood nuclear power plant, but with over 100 other
localities, specimens still are found.