Mazon Creek Fern P-MC-16-012 Lower Cretaceous Most of the original shell

Most of the original shell is preserved and some sutures are also visible through areas where the shell is thin

This unidentified leaf has well defined palmate venation

but fade away on the body chamber

The cephalothorax tapers forward to form an oval shape

Araucarioxylon

Mazon Creek Fern P-MC-16-012 Lower Cretaceous Most of the original shellPecopteris sp. Carbondale Formation Middle Pennsylvanian Grundy County, Illinois Complete siderite nodule with a very well preserved fern frond. The Mazon Creek area fossils are found mostly in siderite concretions. The concretions are found in the Francis Creek Shale Member within the Carbondale Formation of the Kewanee Group. The best nodules are a by product of coal strip mining operations. The age of the fossil plants is Desmoinesian, Middle