Leaf Scars on the bark of Lepidodendron, the dominant tree of the coal swamp forest throughout most of the Pennsylvania Epoch during the Carboniferous Period. This "scale" tree grew to 130 feet. The pattern of leaf scars (~3/4") on the bark lie in a spiral arrangement on the trunk, which could be up to 6' in diameter. The closely packed diamond-shaped leaf scars left on the trunk and stems as the plant grew provide some of the most interesting and common fossils in Carboniferous shales and accompanying coal deposits. Specimen courtesy of Penn State University Museum.