Agate Fossil Beds National Monument is a U.S. National Monument near Harrison, Nebraska. The main features of the monument are a valley of the Niobrara River and the fossils found on Carnegie Hill and University Hill.

The area largely consists of grass-covered plains. Plants on the site include prairie sandreed, blue grama, little bluestem and needle and thread grass, and the wildflowers lupin, spiderwort, western wallflower and sunflowers.

History

thumb|left|Entrance to the monument

thumb|upright=1.4|Map of Agate Fossil Beds

Most of the land that is now the National Monument was part of the Agate Springs Ranch, a working cattle ranch, owned by James and Kate Cook, who bought the ranch in 1887. Another is that animal carcasses were swept down the ancient rivers and deposited there due to the particular geometry of the river bends and eddies. Another is that animals became trapped in quicksand there.

The monument's museum collection also contains more than 500 artifacts from the Cook Collection of Plains Indians artifacts.

The national monument was authorized on June 5, 1965, but was not established until June 14, 1997. The Harold J. Cook Homestead (Bone Cabin Complex) was listed on the National Register of Historic Places in 1977. Agate Fossil Beds is maintained by the National Park Service.

Paleontology

The site is best known for a large number of well-preserved Miocene fossils, many of which were found at dig sites on Carnegie and University Hills. Fossils from the Harrison Formation and Anderson Ranch Formation, which date to the Arikareean in the North American land mammal classification, about 20 to 16.3 million years ago, are among some of the best specimens of Miocene mammals.

Species found in Agate include:

  • Merychippus and Parahippus, ancestors of the modern day horse.
  • Diceratherium, two-horned rhinoceros.
  • Menoceras, pony-sized rhinoceros, the most common animal found in the fossil beds.
  • Daphoenodon and Ysengrinia, two types of mid-sized bear dogs.
  • Promerycochoerus, a semiaquatic hippo-like oreodont.
  • Daeodon, the largest Entelodont (giant pig-like ungulate).
  • Stenomylus, gazelle-like camelids.
  • Oxydactylus, giraffe-like camelids.
  • Palaeocastor, land beavers that dug large corkscrew-shaped burrows (Daemonelix).
  • Moropus, a chalicothere which are relatives of rhinos and horses.
  • Merychyus, a sheep-like oreodont.
  • Syndyoceras, antelope-like mammal and extinct relatives of artiodactyls.

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File:Daemonelix burrows, Agate Fossil Beds.jpg|"Devil's corkscrews", Miocene-age burrows of Palaeocastor, discovered in the late 19th century

File:Bone Cabin, Agate Fossil Beds NM 3.JPG|The Bone Cabin, used during twenty-five years of fossil excavations at the Agate Fossil Beds

File:Niobrara headwaters.JPG|The Niobrara River flowing through Agate Fossil Beds

File:Daemonelix Corkscrew.jpg|A Daemonelix corkscrew fossil exhibit

File:View From Daemonelix Trail.jpg|View of the park from the Daemonelix Trail

File:Agate Hide Pictographs.jpg|Plains Indian pictographs on a hide at the Agate Visitor Center

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See also

  • List of fossil sites
  • List of national monuments of the United States
  • Ashfall Fossil Beds
  • Florissant Fossil Beds National Monument
  • John Day Fossil Beds National Monument
  • Scotts Bluff National Monument

References

  • Official NPS website: Agate Fossil Beds National Monument