Prairie Research Institute


The Prairie Research Institute is home to premier biological and geological research collections. These collections include millions of rare and irreplaceable fossils, subsurface geological samples, and biological specimens.

Biological Collections

With more than 9 million specimens, PRI is home to the most comprehensive documentation of Illinois’ flora and fauna, encompassing amphibians and reptiles, birds, crayfish and other crustaceans, fish, fungi, insects and other arthropods, mammals, microsporidia, mollusks, plants, and segmented worms. As many species continue to decline and disappear in the wild, these collections represent a unique and irreplaceable archive of biodiversity. These specimens can be used to:

  • discover and describe previously unknown species
  • identify and track the spread of invasive species
  • infer evolutionary relationships among organisms
  • document and predict the past, present, and future distributions of species, including endangered species
  • prioritize areas for conservation based on their past and present species diversity
  • develop baselines and targets for habitat restoration
  • document environmental change, such as the presence of chemical pollutants and pathogens
  • track changes in distribution and community composition associated with climate change and other human-induced environmental changes
  • train students for careers in natural resource management, conservation biology, and taxonomy and systematics

Fossil Collection

PRI houses an extensive collection of over 1.5 million fossil specimens from around the world. These collections are used extensively by researchers to piece together the history of our planet.

Particular strengths of PRI’s paleontological collections include fossil plants and insects from the Pennsylvanian period (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.

PRI is home to the world’s largest collection of coal balls— lumps of petrified plant matter found in coal seams of the Upper Carboniferous Period, which are important sources of information relating to the plants and organisms preceding the Coal Age. PRI’s collection includes 50,000 intact coal balls and a 250,000 thin slices or “peels.” This collection provides valuable insights about temperature, humidity, and C02 conditions of the past.

Geological Samples Library

The Geological Samples Library is the sole public repository of Illinois geologic samples, providing vital support for research on geology, mineral and fossil fuel resources, groundwater, and hazards.

  • The Carozzi collection contains over 16,000 specimens of representative rock type from all over the world that were collected by one of the premier petrologists of the 20th Century.
  • Each year 10,000 water wells, about 1,000 oil wells, and thousands of engineering boreholes are completed in Illinois. Samples from these wells are mandated to be sent to the Geological Samples Library, providing valuable insights into Illinois’ geologic conditions.