Calamites cisti


This fossil was collected in 1992 .
Rock Type: Sandstone; fine-grained
Formation: Kanawha
Interval: Coalburg seam
Age: Middle Pennsylvanian Period, approx. 307 million years.

Calamites cisti grew to heights of up to forty (40) feet. Although it is related to the modern horsetail, Calamites cisti actually looked something like a pine tree . It had upward-slanting slender branches arranged concentrically around the trunk in rows spaced several feet apart, and conifer-like needles arranged in whorls around ends of the branches. Though reaching significant heights, the trunk lacked substantial mass, being composed mostly of pithy reed-like tissue, with about the strength of a rolled-up newspaper. Consequently, they tended to fall over very easily, unless supported by neighboring plants or by accumulating sediments.

The specimen shown above is a cast of the inner pith cavity of the main trunk. The vertical rib lines are characteristic of calamites. The nodes (small circular knots along the horizotal bands) are where vascular structures serving leaves and branches were attached. The blunt-ended, closely spaced nature of the ribs and non-constricted nodes are characteristic of the form-species cisti.

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. Follow it about 7 miles. It is now mostly reclaimed, but there is still some good collecting along the exposed rock rip-rap outslope of the sediment ditch along Buffalo Creek.