North Dakota Stratigraphy Plesiadapis ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS OF YEARS AGO Common Name: Holocene Oahe .01 Lemur-like mammal Coleharbor Pleistocene QUATERNARY Classification: 1.8 Pliocene Unnamed 5 Miocene Class: Mammalia 25 Arikaree Order: Primates Family: Plesiadapidae Brule Oligocene 38 South Heart Chadron Jaw of the lemur-like mammal, Plesiadapis. Bullion Creek Chalky Buttes Camels Butte Formation, Billings County. Width 24 mm. Science Museum of Eocene Golden 55 Valley Bear Den Minnesota Collection. Sentinel Butte TERTIARY Description: Plesiadapis was a lemur-like mammal the size of a modern-day beaver, about 2 ½ feet long. They had long tails, agile limbs with Bullion Paleocene Creek claws rather than nails, and eyes placed on the sides of their heads. Unlike modern primates, the head of Plesiadapis had a long snout Slope with rodentlike jaws and teeth and long, gnawing incisors Cannonball separated by a gap from its molars. It was well-adapted for climbing in trees with its long, clawed fingers and toes. Ludlow 65 Plesiadapis inhabited the vast forests that covered western North Hell Creek Dakota when the climate was subtropical, similar to south Florida today. Fox Hills ACEOUS Pierre CRET 84 Niobrara Carlile Carbonate Calcareous Shale Claystone/Shale Siltstone Sandstone Sand & Gravel Mudstone Lignite Glacial Drift Plesiadapis. Painting courtesy of Simon and Schuster Publishing Company. Locations where fossils have been found ND State Fossil Collection Prehistoric Life of ND Map North Dakota Geological Survey Home Page.