Agate Fossil Beds National Monument

Twenty million years ago, Miocene mammals like the bear dog Daphoenodon and the strange Moropus died and were buried along an ancient river here, leaving fossil beds that paleontologists raced to excavate in the early 1900s. The monument also holds the Cook Collection, gifts from Red Cloud and other Lakota to a rancher friend.

Hike the Fossil Hills Trail to the old dig sites and see the spiral Daemonelix burrows. For a challenge, hike both fossil trails across the open Niobrara valley grasslands in one long outing.