Fern Fossil From Mazon Creek - 300 Million Years Old

This is a large Pecopteris fern fossil from Mazon Creek in Illinois. It's Pennsylvanian in age, or approximately 300 million years old. Mazon creek deposits are world famous for their finely preserved fossils found within ironstone nodules. Thousands if not millions of these nodules have been collected over the years from the spoil heaps of abandoned coal mines in the area.