Diminutive Mazon Creek Jellyfish Fossil

Description: The Mazon Creek deposits of the region near Braidwood, Illinois rival the other famous Lagerstatten of the Burgess Shale, Solnhofen, and Liaoning for the variety of detailed life preserved. Many exquisitely-preserved specimens are found in the ironstone nodules that make up the deposits. The majority of collecting areas are the spoil heaps of abandoned coal mines, the most famous of which 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 come to light. The example here is a small jellyfish known as Octomedusa pieckorum. It derives its generic name from the fact that it has 8 tentacles which vary from mere nubs to ones that extent out to a length equal to the diameter of the bell; several are visible here. The indistinct cross-like structure is thought to be the quadripartite mouth. Members of the Coronatida today contain the smallest extant jellyfish. This one represents an opportunity to add this rare jellyfish to your collection of Mazon Creek fossils.