Dinosaur National Monument is an American national monument located on the southeast flank of the Uinta Mountains on the border between

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

at the confluence of the

Green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

and Yampa rivers. Although most of the monument area is in Moffat County, Colorado, the Dinosaur Quarry is located in Utah, north of the town of Jensen, Utah. The nearest Colorado town is

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

while the nearest city is Vernal, Utah. Originally preserved in 1915 to protect its famous Dinosaur Quarry, the monument was greatly expanded in 1938 to include its wealth of natural history. The park's wild landscapes, topography, geology, paleontology, and history make it a unique resource for both science and recreation. The park contains over 800 paleontological sites and has fossils of

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s including ''

Allosaurus ''Allosaurus'' () is a genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch ( Kimmeridgian to late Tithonian). The name "''Allosaurus''" means "different lizard" alludi ...

'', '' Deinonychus'', ''

Abydosaurus ''Abydosaurus'' (meaning " Abydos lizard") is a genus of brachiosaurid sauropod dinosaur known from skull and postcranial material found in upper Lower Cretaceous rocks of northeastern Utah, United States. Discovery ''Abydosaurus'' is one of th ...

'', and various sauropods. The ''Abydosaurus'' consists of a nearly complete skull, the lower jaw, and first four neck vertebrae. The specimen was found at the base of the Mussentuchit Member of the Cedar Mountain Formation and is the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

for the description. Paleontologist Earl Douglass of the Carnegie Museum discovered eight vertebra of an Apatosaurus on August 17, 1909, which became the first dinosaur skeleton discovered and excavated at the new Carnegie Quarry. The area around the quarry was declared a national monument on October 4, 1915. The International Dark-Sky Association designated Dinosaur National Monument an International Dark Sky Park in April 2019.

Geology

The rock layer enclosing the fossils is a

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

and

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

bed of

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Al ...

or river bed origin known as the Morrison Formation from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Period some 150 million years old. The dinosaurs and other ancient animals were carried by the river system which eventually entombed their remains in Utah. The pile of sediments were later buried and lithified into solid rock. The layers of rock were later uplifted and tilted to their present angle by the mountain building forces that formed the Uinta Mountains during the Laramide orogeny. The relentless forces of

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...

exposed the layers at the surface to be found by paleontologists.

History

Fremont people

Matriarch - Petroglyphs in Dinosaur National Monument

The Fremont people lived in the area of what is now Dinosaur National Monument before the 14th century, with archaeological evidence dating from 200 to 1300. Archaeologists first studied and named the Fremont culture along the Fremont River in south-central Utah and have since traced it through much of the Green and Colorado River drainages. The Fremont did not build large permanent dwellings; instead, they lived in small bands within natural shelters, such as rock overhangs or shallow caves, or small villages. They consumed plant foods, such as pine nuts, berries, and

cactus A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Gre ...

fruits, as well as wild game, including

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whit ...

, bighorn sheep, smaller mammals, and birds. They also grew corn, beans, and squash, sometimes using irrigation techniques. The fate of the Fremont culture is unclear. Recent theories suggest that the Fremont’s lifestyle may have changed due to drought or other climate factors, dwindling natural resources, or the influence of other neighboring cultures. They left evidence of their presence in the form of

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

s and pictographs of human and animal figures, and abstract designs. Human figures typically have trapezoidal bodies and elaborate decorations that suggest headdresses, earrings, necklaces, or shields. The animal figures include bighorn sheep, birds, snakes, and lizards. Purely abstract or geometric designs, such as circles, spirals, and various combinations of lines, are common. Many designs in the monument are accessible for close viewing, along four trails in Utah, one of which is near the visitor center, and a fifth trail in Colorado.

Early scientific explorations

The dinosaur fossil beds ( bone beds) were discovered in 1909 by Earl Douglass, a

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...

working and collecting for the Carnegie Museum of Natural History. He and his crews excavated thousands of

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

and shipped them back to the museum in

Pittsburgh, Pennsylvania Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsyl ...

for study and display.

National monument

President

Woodrow Wilson Thomas Woodrow Wilson (December 28, 1856February 3, 1924) was an American politician and academic who served as the 28th president of the United States from 1913 to 1921. A member of the Democratic Party, Wilson served as the president of P ...

proclaimed the dinosaur beds as Dinosaur National Monument in 1915. The monument boundaries were expanded in 1938 from the original surrounding the dinosaur quarry in Utah, to in Utah and Colorado, encompassing the river canyons of the

and Yampa.

Echo Park Dam controversy

The plans made by the

U.S. Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...

on a ten-dam, billion dollar Colorado River Storage Project began to arouse opposition in the early 1950s when it was announced that one of the proposed dams would be at Echo Park, in the middle of Dinosaur National Monument. The controversy assumed major proportions, dominating conservation politics for years. David Brower, executive director of the Sierra Club, and

Howard Zahniser Howard Clinton Zahniser (February 25, 1906 – May 5, 1964) was an American environmental activist. For nearly 20 years, he helped lead The Wilderness Society as executive secretary, executive director, and editor of ''The Living Wilderness'', fro ...

of The Wilderness Society led an unprecedented nationwide campaign to preserve the free-flowing rivers and scenic canyons of the Green and Yampa Rivers. They argued that if a national monument was not safe from development, how could any wildland be kept intact? On the other side of the argument were powerful members of Congress from western states, who were committed to the project in order to secure water rights, obtain cheap

hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined a ...

and develop reservoirs as tourist destinations. After much debate, Congress settled on a compromise that eliminated Echo Park Dam and authorized the rest of the project. The Colorado River Storage Project Act became law on April 11, 1956. It stated, "that no dam or reservoir constructed under the authorization of the Act shall be within any National Park or Monument."

Historic places

Places on the list of National Register of Historic Places include: : Prehistoric sites :* Castle Park Archeological District, a prehistoric residential site with inhabition during 1500 - 1000 BC and again from AD 1000 - 1899 by the Prehistoric

Fremont culture The Fremont culture or Fremont people is a pre-Columbian archaeological culture which received its name from the Fremont River in the U.S. state of Utah, where the culture's sites were discovered by local indigenous peoples like the Navajo and ...

, Ute and Shoshone people. :* Mantle's Cave is a prehistoric

residential site from 499 BC - AD 1749. :Other sites :* Josie Bassett Morris Ranch Complex :* Denis Julien Inscription :* Rial Chew Ranch Complex :*

Upper Wade and Curtis Cabin The Upper Wade and Curtis Cabin was built in 1933 by John Grounds in Dinosaur National Monument. The rustic building served as a guest lodge and ranger station, and is listed on the National Register of Historic Places The National Register ...

Climate

The Dinosaur National Monument sits on a vast area of desert land in Northwestern Colorado and Northeastern Utah. Typical of high deserts, summer temperatures can be exceedingly hot, while winter temperatures can be very cold. Snowfall is common, but the snow melts rapidly in the arid and sunny climates of these states. Rainfall is very low, and the evaporation rate classifies the area as desert, even though the rainfall exceeds 10 inches.

Features

The quarry

Dinosaur National Monument Quarry Exhibit Hall

The "Wall of Bones" located within the Dinosaur Quarry building in the park consists of a steeply tilted (67° from horizontal) rock layer which contains thousands of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s. The preserved section is only a portion of what was originally present when Douglass made his discovery as seen on the map above. When work ceased in 1922, a portion of the quarry was left for future development. This work began as part of President Franklin Roosevelt's Civil Works Administration, which provided employment during the Depression under the Transient Relief Service and later under the Works Progress Administration. This work included constructing a road to the quarry, removal of overburden covering the bone-bearing strata, and building of a small, temporary museum. The War interrupted work but this was resumed in 1951 with the building of a small metal building over the east portion of the quarry to test whether bone was abundant enough to warrant a larger, more permanent building. This more permanent building was erected in the mid-1950s as part of the National Park Service Mission 66 plan. The architectural design was high controversial for its ultra-modern use of glass, steel and concrete ramp that spiraled around a cylindrical office tower. The building opened at the dedication ceremony on June 1, 1958. The design had two levels and abundant natural light so that visitors could watch technicians remove the hard rock to reveal the fossil bones in-situ. In July 2006, the

Quarry Visitor Center Quarry Visitor Center, in Dinosaur National Monument in Utah was built as part of the National Park Service's Mission 66 program of modern architectural design in the US national parks. This visitor center exemplifies the philosophy of locatin ...

was closed due to structural problems that since 1958 had plagued the building because it was built on unstable clay. The decision was made to build a new facility elsewhere in the monument to house the visitor center and administrative functions, making it easier to resolve the structural problems of the quarry building while still retaining a portion of the historic Mission 66 era exhibit hall. It was announced in April 2009 that Dinosaur National Monument would receive $13.1 million to refurbish and reopen the gallery as part of the Obama administration's $750 billion stimulus plan. The Park Service successfully rebuilt the Quarry Exhibit Hall, supporting its weight on 70-foot steel micropile columns that extend to the bedrock below the unstable clay. The Dinosaur Quarry was reopened in Fall 2011.

Fossils from Carnegie Quarry

Dinosaur National Monument-inside the Dinosaur Quarry building

:Now enclosed by the Dinosaur Quarry building (Gilmore (1936), Foster (2003); Good (2004). ;Planta :Coniferophyta ;Mollusca :''Unio'' sp. :''Vetulonia'' sp. ;Reptilia :Testudines ::Amphichelydia :::'' Glyptops plicatus'' :::''

Dinochelys ''Dinochelys'' (from Greek ''deinos'' -terrible- and ''chelys'' -turtle) is an extinct genus of paracryptodiran turtle from the Late Jurassic Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic, Upper Jura ...

whitei'' :Rhynchocephalia :::'' Opisthias rarus'' :Crocodilia ::Mesosuchia :::Gonipholididae ::::'' Goniopholis'' sp. :::Atoposauridae ::::''

Hoplosuchus ''Hoplosuchus'' is a genus of crocodylomorph belonging to Protosuchidae. It is so far only known definitely from one specimen, a skeleton collected from sandstone of the Upper Jurassic-age Morrison Formation rocks at Dinosaur National Monument, ...

kayi'' (h) ;Dinosauria :Saurischia ::Theropoda :::'' Ceratosaurus'' sp. :::'' Torvosaurus'' sp. :::''

fragilis'' ::Sauropoda :::'' Apatosaurus louisae'' (h) :::'' Barosaurus lentus'' :::'' Camarasaurus lentus'' :::'' Diplodocus hallorum'' :::''

Uintasaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch ( Kimmeridgian to T ...

douglassi'' (h) (now ''Camarasaurus lentus'') :Ornithischia ::Stegosauria :::'' Stegosaurus'' ungulatus ::Ornithopoda :::Iguanodontia ::::'' Camptosaurus aphanoecetes'' (h) :::Dryosauridae ::::'' Dryosaurus elderae'' (h) :(h) = holotype

References

External links

* * * {{authority control National Park Service National Monuments in Colorado National Park Service National Monuments in Utah Fossil parks in the United States Dinosaur museums in the United States Natural history museums in Utah Museums in Uintah County, Utah Features of the Uinta Mountains Green River (Colorado River tributary) Protected areas of Moffat County, Colorado Protected areas of Uintah County, Utah Paleontological protected areas in the United States Paleontology in Colorado Paleontology in Utah Morrison Formation Jurassic Colorado Jurassic geology of Utah Jurassic paleontological sites of North America Environmental controversies Sierra Club Protected areas established in 1915 1915 establishments in Colorado 1915 establishments in Utah 1915 establishments in the United States Badlands of the United States