The diamond-shaped structures on this specimen are leaf scars of Sigillaria brardii. In the center of each scar is a dimple that is horizontally-elongated, with an occassional dot of coal in the center. A leaf of Sigillaria was attached at each of these scars in life. These details are more easily seen in this close-up view.
These structures called leaf cushions are typically 5 x 7 mm across and are characteristically rounded at the bottom margins while the top surfaces are flat with sharp, lateral corners. See this high magnification view.
This specimen was provided courtesy of Gary Wolfe.
Rock Type: Gray shale
Formation: Kanawha
Interval: Stockton seam
Age: Middle Pennsylvanian Period, approx. 305 million years.
Location: Kanawha County, West Virginia; Catenary Coal. Co., Samples
Mine, located about 10 miles south of Cabin Creek, West Virginia, just west
of Route 79/3. It is an active surface mine and requires permission for
access.
