Monday, June 15, 2009

Fossil Fern Pecopteris or Alethopteris

Here is another plant fossil that Shamalama found that is very nice. It is taking me a while to read the section on vascular plants in the Fossil of Ohio book. I am guessing this might be a Pecopteris or Alethopteris from the Late Carboniferous or Pennsylvanian period. It was found in Schuylkill County, Pennsylvania in the Llewellyn Formation.

This frond was preserved in a swamp like environment that allowed its organic parts to be replaced by sulphides (pyrite) over time. Later the pyrite was replaced by aluminum silicate (pyrophyllite) giving it a white like look.

I attached a picture of a modern day fern I took for comparison.