Name:   Fossil Seed Fern Fronds Age:  Pennsylvanian Formation:  Llewellyn Formation Location:  Near St. Clair, Pennsylvania Size:  Plate is 14.7 inches tall This is a very nice fossil plant from the now-closed location near St. Clair, Pennsylvania. The fossil fern fronds are preserved as a thin film of white pyrophyllite on black shale. The detail of this fossil is quite nice, and the fronds are quite large. And there are also fronds on the back side of the plate! This is a very good example of large fossil fern fronds from the Coal Regions of Pennsylvania.