The Prairie Research Institute is home to an extensive collection of fossils from around the world. These specimens help us gain new insights about what Earth was like millions of years in the past.

Particular strengths of PRI’s paleontological collections include fossil plants and insects from the Pennsylvanian (Upper Carboniferous) of Illinois, a large collection of Midwestern Pleistocene mollusks, the historically significant Milton Sanderson collection of Early Miocene amber from the Dominican Republic, and a rapidly growing collection of fossil insects from across the globe, ranging in age from Carboniferous to Pleistocene.

The Milton Sanderson Amber Collection

The Milton Sanderson Amber Collection at the Prairie Research Institute represents the first collection of early Miocene Dominican amber ever made, and the only unbiased collection in existence. Beetle expert Dr. Milton Sanderson (1910–2012) gathered the collection’s 160 pounds of amber—roughly 140,000 individual pieces—while doing fieldwork in the Dominican Republic in 1959.

The Renova Formation of Montana

The finely laminated shale beneath my feet is all that remains of an ancient lake that dominated this area during the Oligocene, some 23 million to 33 million years ago. Thin layers of clay and volcanic ash preserved beautifully the remains of insects and plants, providing a glimpse of an ancient ecosystem. This remarkable fossil deposit has drawn me and my team here to explore a world long since lost to deep time.

The Renova Formation was formed during a dynamic point in Earth’s history—the Oligocene epoch (23 million to 33 million years ago), a time of gradual transition from a tropical to a temperate climate in southwest Montana. This remarkable deposit

The Green River Formation of Colorado

Located in western Colorado, the Green River Formation contains a vast quantity of beautifully-preserved plants, insects, and vertebrates from the Eocene epoch (49.7 and 50.7 million years ago). PRI possesses a small collection of insect fossils from the formation, many of which are still undescribed.

The Crato Formation of Brazil

The Crato Formation is an Early Cretaceous limestone deposit located in the Araripe Basin in the northeastern part of Brazil. This deposit showcases amazing preservational fidelity—even soft parts of organisms are preserved in three dimensions.