6" Alethopteris Fern Plant Leaf Fossil Carboniferous Age Llewellyn FM ST Clair, PA

Location: Llewellyn Formation, St Clair, Pennsylvania Weight: 8.8 Ounces Dimensions: 6 Inches Long, 4.1 Inches Wide, 0.5 Inches Thick (Plate) Comes with a Certificate of Authenticity. Comes with a Free Stand. The item pictured is the one you will receive. Pennsylvanian Age, 300 million years old. Alethopteris Sp Fern Fossil These plant fossils were found in the Llewellyn Formation (300 million years ago, Pennsylvanian Period) and are one of the few places where one can find these very detailed, white (sometimes yellow) ferns on a striking contrast of black shale. The plants died and fell into the swamp, where, in a low-temperature, high-pressure, and low-oxygen environment, the plant tissue was slowly replaced by pyrite (from sulfides). Pyrophyllite (aluminum silicate, a whitish mineral) is believed to have replaced the pyrite at a later stage as the sediments piled up and the temperature and pressure became greater. The ferns most commonly found are Alethopteris, Neuropteris, Pecopte