The vertebrate paleontology collection consists mainly of Cenozoic mammals, Jurassic and Cretaceous Dinosaurs, Cretaceous seaway fish and reptiles, and includes a number of complete skeletons. The paleobotany collection consists mainly of Cretaceous-Eocene leaves and is the second largest collection of its kind in the nation. The invertebrate paleontology collection's main strengths are Cambrian-Ordovician trilobites, Cretaceous seaway mollusks, and Eocene insects. The gem and mineral collection focuses on Colorado and includes a number of regional iconic specimens. The micromount mineral collection is the second largest in the nation and contains specimens from around the world. The rock collection includes historical and building-stone collections. The meteorite collection has samples from around the world with a significant fraction from Colorado.

The collections in the Department of Earth Science date to the founding of the Museum. Numerous important donations including the Campion Gold, and the Museum's first field expedition, were crucial to building the geological and paleontological collections in the 1910s and 20s. Between the 1930s and 1960s the Department's collections were the focus of numerous major permanent exhibits on fossils mammals, dinosaurs, and minerals. The Department's current structure was developed in the late 1980s with the hiring of Richard Stucky. The current staff represents the largest ever for the Department and includes four curators.

Research in DES is specimen and field-based and focused on the Rocky Mountain region. There are six active researchers in the department who focus on Mesozoic and Cenozoic fossil plants and mammals; Paleozoic and Mesozoic reptiles, dinosauromorphs and dinosaurs; Paleozoic invertebrates; and stratigraphy and tectonic evolution of Mesozoic and Cenozoic basins in the American West. All DES researchers maintain active field programs.

The Earth Sciences Department strives to effectively engage the general public and media. Efforts include citizen science, popular talks, tours, and articles, science documentaries, and the Paleontology Certification Program. In the last year, the Earth Science Department volunteers have logged approximately 35,000 hours, and staff has given more than 100 popular talks and tours. There have been more than 500 national and international news articles on Department-related research and there have been numerous national broadcasts by curators.

The Earth Sciences Department provides access to the more than 200,000 paleontological and geological specimens in the collections to external researchers. Staff are active as editors with numerous professional journals and as committee members or past presidents of national organizations.

Paleobotany Project

This Web-based collection of fossil plants from Colorado, Utah, and Wyoming caters to paleobotanists. Identify your own fossils and submit specimens to the Museum to be posted on the Web. Access the database.