Here is a nice concretion form Mazon Creek with two fossil leafs of the species Pecopteris fontainei and Neuropteris blissi. | |||
Location: | Mazon Creek, Braidwood, Illinois , USA | ||
Size of concretion : | about 80 x 52 mm | ||
Age: | Upper Carboniferous, Pennsylvanian , Carbondale Fm. (about 300 Ma) |