Florissant Fossil Beds National Monument is a United States National Monument in Teller County, Colorado, that is noted for its fossils. It is located in a mountain valley just west of Pikes Peak and holds spectacular remnants of prehistoric life. The fossil beds take their name from the nearby town of Florissant, Colorado.
The fossils are contained in the Florissant Formation of Eocene age. Huge petrified redwoods and very detailed fossils of ancient insects and plants reveal a very different landscape in Paleogene Colorado. Almost 35 million years ago, enormous volcanic eruptions - now designated the Thirtynine Mile Volcanic Area - buried the then-lush valley and petrified the redwood trees that grew there.