This is a large specimen of Lepidodendron bark from the Pennsylvanian of Iowa. Lepidodendron trees were very important in the formation of coal in the mid-continent area. The diamond-shaped pattern of the bark is beautifully defined. Each "diamond" represents the point of attachment of a fallen leaf. The dark brown color of the fossil is quite striking. This is a great example of this unique fossil bark from the Coal Age.