Mazon Creek fossils

Mazon Creek fossils are exceptionally preserved plant and animal fossils from the Pennsylvanian period (about 309 million years ago) found in ironstone concretions in northeastern Illinois. The fossils are significant for their high diversity, including a wide range of marine and terrestrial life like plants, insects, sharks, jellyfish, and even early tetrapods, preserved together due to a unique delta environment. The concretions are often cracked open using freeze-thaw cycles to reveal the fossils inside. 

Each fossil comes in a set and includes 2 acrylic holders.