Neuropteris fern fronds with pyrite; some of the most widespread of all Pennsylvanian Epoch seed ferns. Specimens ~4" in lenth. Fronds are accented by pyrite deposition (gold color). A gymnosperm from the Carboniferous Period, Pennsylvanian Epoch, some 300 million years ago. Specimen courtesy of Pennsylavnia State Museum, Klose Coal Fossil Collection.