3" Fossil Horsetail (Sphenophylum) - Pennsylvania

This is a Pennsylvanian aged fossil horsetail (Sphenophylum) from the Llewellyn formation of Pennsylvania. The white color of these detailed fern fossils contrasts well against the black shale they are preserved in. These plants were buried in a swamp where a low temperature, pressure, and oxygen environment the plant tissue was slowly replaced by pyrite. This pyrite was later replaced by a whitish mineral (aluminum silicate) as the fossils were buried and exposed to the heat and pressure inside of the earth.

A display stand is included with the purchase.