Arguably one of the most commonly preserved, showy and recognizable of the Mazon Creek flora are the ferns. These are formed in Ironstone nodules that are found in the waste dumps of coal mines. Formed during the Mississippian period the area around Mazon Creek, Francis Creek and Mazonia State Park in Illinois these are often prized by fossil collectors.
Ironstone nodules consist of more than 15% iron, such as siderite. The Mazon Creek fossils are found in yellow-brown or orange brown sedimentary nodules.
Unfortunately much of the land where these are found is now private property, ferns and plants such as this are becoming harder and harder to come across.
This is a split pair specimen that is in an ironstone nodule 1.94 inches by 1.39 inches wide.
Francis Creek Shale
Specimen in the picture is the specimen you will receive.