North Dakota Stratigraphy Tyrannosaurus rex ROCK ROCK UNIT COLUMN PERIOD EPOCH AGES MILLIONS OF YEARS AGO Common Name: Holocene Oahe .01 Tyrant reptile king Coleharbor Pleistocene QUATERNARY Classification: 1.8 Pliocene Unnamed 5 Miocene Class: Reptilia 25 Arikaree Order: Saurischia Family: Tyrannosauridae Brule Oligocene 38 Tyrannosaurus rex shed tooth. Tooth collected in Morton South Heart Chadron Chalky Buttes County. Height of tooth is 64 mm. North Dakota State Fossil Camels Butte Eocene Golden Collection. 55 Valley Bear Den Description: Sentinel Butte Tyrannosaurus rex was one of the largest carnivorous (meat TERTIARY eating) dinosaurs and was one of the largest terrestrial carnivores yet known. The adults grew to lengths of 40 feet from the end of the tail to tip of the nose and weighed about 8 tons. When they Bullion Paleocene Creek stood on their hind legs they were up to about 20 feet tall. They had huge heads, about 5 feet long, and possessed large, Slope approximately 50, dagger-like teeth, some as large as bananas. Cannonball The teeth, which were serrated, could puncture bone and carve Ludlow through flesh of prey. Its back legs were long, heavily built, and 65 powerful with 3 clawed toes on each foot. Each foot was broad Hell Creek with three forward-pointing toes. Each toe ended in a sharply- curved talon. T. rex’s arms were very short and contained hands Fox Hills with only two, clawed fingers on each hand. Its tail was long, heavy, and held off the ground to act as a counterbalance. They ACEOUS could tear off as much as about 500 pounds of flesh at one time Pierre with their powerful jaws. They had a keen sense of smell and could CRET travel at high speeds for short distances. Hadrosaurs, the 84 duckbilled dinosaurs, were among the prey of T. rex. Niobrara Carlile No complete skeletons of T. rex have been found in North Carbonate Calcareous Shale Claystone/Shale Dakota, but T. rex teeth and bones have been recovered from Siltstone Sandstone Sand & Gravel several fossil sites in the state. Mudstone Lignite Glacial Drift Tyrannosaurus rex. Painting by, and courtesy of, John Sibbick. Locations where fossils have been found ND State Fossil Collection Prehistoric Life of ND Map North Dakota Geological Survey Home Page.