Agate Fossil Beds is a US National Monument which contains a valley of the Niobrara River and the fossil beds located on Carnegie Hill and University Hill. Agate Fossil Beds is maintained by the National Park Service.

The Niobrara river valley consists of grass-covered plains with the fauna including: prairie sandreed, blue grama, little bluestem, needle and thread grass, and the wildflowers lupin, spiderwort, western wallflower and sunflowers.

The fossils in the beds on Carnegie and University Hills are from the Miocene Epoch. Some of the species found at the Agate beds include: beavers (Palaeocastor), horse (Merychippus), two-horned rhinoceros (Daphoenodon), pony-sized rhinoceros (Menoceras), bear dog (Daphoenodon), an semi-aquatic hippo (Promerycochoerus), giant pig-like ungulate (Daeodon), gazelle-like camelids (Stenomylus), giraffe-like camelids (Oxydactylus), sheep-like hog (Merychyus), antelope-like mammal (Syndyoceras) and others.

Before becoming the national monument the property was a cattle ranch called the Agate Springs Ranch and owned by Captain James Cook, who had a personal collection of more than 500 artifacts from the Plains Indians located in his Bone Cabin. The homestead of Captain Cook (Bone Cabin) was listed on the National Register of Historic Places in 1977.

When the national monument was authorized on 5 June 1965, Captain Cook donated most of his collection to be part of the monument museum, but the actual monument was not established until 14 June 1997.

These fossil beds are located near Harrison, Nebraska

The Lakota are a Native American people who are also known as the Teton Sioux, and are one of the three prominent subcultures of the Sioux people, including the Lakota, Dakota and Western Dakota. Their current lands are in North and South Dakota and most speak the Lakota language, the westernmost of three closely related languages that belong to the Siouan language family of languages.

The seven bands of the Lakota are:

Sihangu (Burned Thighs)

Oglala (They Scatter their Own)

Itazipcho (Without Bows)

Hunkpapha (End Village)

Miniconjou (Plant Near Water)

Sihasape (Blackfeet)

Oohenunpa (Two Kettles)

Notable Lakota persons include: Sitting Bull of the Hunkpapa band, Touch the Clouds of the Miniconjou band; Black Elk of the Oglala band; Red Cloud of the Oglala band; Billy Mills of Oglala band; Crazy Horse of the Oglala and Miniconjou band; Spotted Tail of the Sicangu band; and Russell Means of the Oglala band.