AGATE FOSSIL BEDS NATIONAL MONUMENT


Meaning of AGATE FOSSIL BEDS NATIONAL MONUMENT in English

Natural "depository" of an extinct animal community on the Niobrara River, northwestern Nebraska, U.S. The beds, laid down as sedimentary deposits 20 million years ago, bear the remains of prehistoric mammals.

Discovered 0441; 1878, the site was named for its proximity to rock formations containing agates. A national monument since 1965, it covers 2,269 acres (918 hectares).

Britannica Concise Encyclopedia.      Краткая энциклопедия Британика.