This specimen illustrates the thin, outer-bark of calamites cisti_. Such examples are relatively rare, as usually only the pattern of the inner pith cavity is perserved.
Rock Type: Sandstone; fine-grained
Interval: Coalburg seam
Age: Middle Pennsylvanian Period, approx. 307 million years.
Location: Nicholas County, West Virginia; Ramp Run Surface Mine #1, located about 12 miles north of Summersville, West Virginia. Turn west off route 19 north of Summersville onto Spruce Run Road.