5.8" Fossil Horsetail (Annularia) - Mazon Creek

This is a beautiful specimen of Annularia stellata from the famous Mazon Creek Lagerstatten of Illinois. Annularia is a plant fossil from the Carboniferous period. They are the leaf whorls of an extinct horsetail. These horsetails,grew to a height of 30 feet in a tree-like form. They were indicative of a humid, web habitat such as a lake shore. This finely preserved specimen was found inside of an ironstone nodule and both sides of the nodule are included.

The Mazon creek deposits are world famous for their finely preserved fossils found within these 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.