Dinosaur National Monument is located in northwest Colorado and northeast Utah near the northern edge of the Colorado Plateau [Map]. The Yampa River, the last free-flowing river in the Colorado River system, joins the Green River in the monument at Echo Park, named by explorer John Wesley Powell in 1869 during his first scientific expedition on the Colorado Plateau. Today visitors to the monument enjoy rafting the rivers, hiking, camping, and viewing the dinosaur fossils in the Jurassic quarry.
Established in 1915, Dinosaur National Monument encompasses over 200,000 acres and four major river canyons. Over the last 70 million years, the surface rock has been eroded to a depth of 2-3 miles, displaying a geologic stratigraphic record of the Earth's last 1.1 billion years. This is greater than even that of the Grand Canyon, making it an unparalleled site for studies in the field of geomorphology.
The monument gained its name after the discovery of an extensive Jurassic quarry in the western tip of the monument by Earl Douglass in 1909. The quarry preserves the fossilized remains of countless dinosaurs, reptiles and amphibians that were grounded in the mud 120 million years ago. During early excavations, large numbers of fossils were removed from the quarry and sent to Pittsburgh's Carnegie Museum, but most of the bones uncovered since the 1950s have been left in situ on the quarry face. This unique site allows unmatched research opportunities into vertebrate paleontology and the Jurassic paleoenvironment. Fossils from other geologic periods are also found throughout the monument.
Pinyon-juniper woodlands and semi-arid scrub, dominated by sagebrush, cover much of the monument. Domestic grazing and fire suppression have allowed sagebrush and juniper encroachment into grasslands, as well as the establishment of exotics such as cheatgrass and Russian thistle. Riparian corridors line the Yampa and Green, providing critical habitat for numerous wildlife species. Exotic tamarisk is abundant along the Green River.
Many species of mammal inhabit the park, including pronghorn antelope, mule deer, bobcat, fox, badger and beaver. The canyon walls are home to goshawk, turkey vulture, several species of hawk, and even Canada geese in the winter. Extirpated in the 1930s, bighorn sheep have been successfully reintroduced into the park. Some federally listed endangered species, including the bald eagle, peregrine falcon, Colorado squawfish, and razorback sucker, live in the monument either all year or seasonally. Gray wolf, bison and grizzly bear have long been extirpated from the monument.
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Posted by Dinosaurs World at 9:32 PM