North Dakota Stratigraphy Poebrotherium ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS OF YEARS AGO Common Name: Holocene Oahe .01

Coleharbor Pleistocene QUATERNARY Classification: 1.8 Pliocene Unnamed 5 Class: Mammalia 25 Arikaree Order: Artiodactyla Family: Brule

38 South Heart Chadron Description: Chalky Buttes

Camels Butte first evolved in North America, and modern camels are the Golden 55 Valley Bear Den remnants of a formerly much more widespread and diverse group. Poebrotherium was one of these early camels that inhabited the Sentinel Butte open-woodland areas of North Dakota about 30 million years TERTIARY ago. They were lightly built and were goat-sized, about 3 feet long. Their head, with a distinctive narrow snout, and long neck looked similar to a modern-day . Their slender, hind legs Bullion

Paleocene Creek were longer than their forelegs and they had hoofed toes. They were efficient runners. Poebrotherium had long jaws and their

Slope front teeth extended forward as in living camels which allowed the

Cannonball to snip off vegetation.

Ludlow 65

Hell Creek

Fox Hills

ACEOUS Pierre CRET

84 Niobrara

Carlile

Carbonate Calcareous Shale Claystone/Shale

Siltstone Sandstone Sand & Gravel

Mudstone Lignite Glacial Drift

Poebrotherium. Painting courtesy of Kingfisher Publications.

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