File:Menoceras sp. bonebed (fossil rhinoceros) (Harrison Formation, Lower Miocene; Nebraska, USA) 3 (31727527703).jpg

Menoceras sp. - fossil rhinoceros bonebed from the Miocene of Nebraska, USA. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)

From museum signage: "Rhinoceros Graveyard

One of the most notable discoveries in the Harrison Formation of western Nebraska was a thick layer (up to 20 inches) of Early Miocene mammal bones. Most of the bones in this layer belong to Menoceras, an extinct rhinoceros.

What happened 21 million years ago that produced such a vast accumulation of bones?

Evidence from the bones and surrounding sediment suggests to paleontologists that large numbers of animals died during a natural catastrophe, such as a drought. Their bony remains were swept together and carried downstream by heavy rains.

As the skeletons tumbled in the floodwater, many broke apart, although some bones, including a few strings of vertebrae, remain connected. Finally, the bones came to rest in relatively quiet backwater, where they accumulated to form this lasting record of life and death.

Agate Fossil Beds National Monument

In 1904, Carnegie Museum paleontologist O.A. Peterson began excavating an incredible layer of Miocene mammal bones near Agate Springs in western Nebraska.

Most of the bones were those of the extinct rhinoceros Menoceras. Later, Peterson uncovered the small camel Stenomylus and the powerful bear dog Daphoenodon. Other museums sent collecting teams to this area of Nebraska, and the site soon became famous for its excellently preserved fossils.

In 1965, the U.S. Congress authorized the establishment for Agate Fossil Beds National Monument, where this treasure trove of fossil history is preserved for the public. "

Classification: Animalia, Chordata, Vertebrata, Mammalia, Perissodactyla, Rhinocerotidae

Stratigraphy: Harrison Formation, Lower Miocene

Locality: Agate Fossil Beds National Monument, western Nebraska, USA

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