Allen L. Cook Spring Creek Preserve is a 4700 acres (19 km²) nature reserve

Nature reserve

A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...

 considered to be the richest cache of undisturbed dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 fossils in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. It is located near the village of Rock River, Wyoming

Rock River, Wyoming

Rock River is a town in Albany County, Wyoming, in the United States. As of the 2000 census, the town population was 235.-Geography:Rock River is located at ....

 some 40 miles (64.4 km) northwest of Laramie

Laramie, Wyoming

Laramie is a city in and the county seat of Albany County, Wyoming, United States. The population was 30,816 at the . Located on the Laramie River in southeastern Wyoming, the city is west of Cheyenne, at the junction of Interstate 80 and U.S. Route 287....

. The Preserve contains the outcrops of the Morrison

Morrison Formation

The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...

, Sundance

Sundance Formation

The Sundance Formation is a western North American sequence of Upper Jurassic age marine shales, sandy shales, and sandstones.The Sundance Formation underlies the western North American Morrison Formation, the most fertile source of dinosaur fossils in the Americas, and is separated by a...

, and Cloverly

Cloverly Formation

The Cloverly Formation are Lower Cretaceous strata located in Montana and Wyoming, in the western United States. The term now includes strata that had formerly been called the Dakota Formation in central and southern Wyoming.-Members:...

 formations.

The preserve was established in December 2005 when rancher Allen L. Cook donated the land to the University of Pittsburgh

University of Pittsburgh

The University of Pittsburgh, commonly referred to as Pitt, is a state-related research university located in Pittsburgh, Pennsylvania, United States. Founded as Pittsburgh Academy in 1787 on what was then the American frontier, Pitt is one of the oldest continuously chartered institutions of...

, which uses it for research and educational purposes, in partnership with the Carnegie Museum of Natural History

Carnegie Museums of Pittsburgh

Carnegie Museums of Pittsburgh are four museums that are operated by the Carnegie Institute headquartered in the Oakland neighborhood of Pittsburgh, Pennsylvania...

 and the University of Wyoming

University of Wyoming

The University of Wyoming is a land-grant university located in Laramie, Wyoming, situated on Wyoming's high Laramie Plains, at an elevation of 7,200 feet , between the Laramie and Snowy Range mountains. It is known as UW to people close to the university...

.