The area largely consists of grassyplains, which are covered in wild grasses including prairie sandreed, blue grama, little bluestem and needle-and-thread, and the wildflowers lupine, spiderwort, western wallflower and sunflowers.
The Monument is best known, however, for the large number of well-preserved fossils which have been discovered, particularly at dig sites on Carnegie and University Hills. Fossils from the site are among some of the best specimens of Miocenemammals, such as Miohippus, an ancestor of the modern horse, and Menoceras, a three-toed, pony-sized rhinoceros.