Dinosaur National Monument is an American national monument located on the southeast flank of the

Uinta Mountains The Uinta Mountains ( ) are an east-west trending chain of mountains in northeastern Utah extending slightly into southern Wyoming in the United States. As a subrange of the Rocky Mountains, they are unusual for being the highest range in the ...

on the border between

Colorado Colorado (, other variants) is a state in the 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 western edge of the ...

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 nm. In subtractive color systems, used in painting and color printing, it is created by a combin ...

and Yampa rivers. Although most of the monument area is in

Moffat County, Colorado Moffat County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 13,292. The county seat is Craig. With an area of 4,751 square miles, it is the 2nd largest county by area in Colorado, behind Las A ...

, the Dinosaur Quarry is located in Utah, north of the town of

Jensen, Utah Jensen is a census-designated place in eastern Uintah County, Utah, United States. The population was 412 at the 2010 census. It lies along the Green River and U.S. Route 40, southeast of the city of Vernal, the county seat of Uintah County, ...

. 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'', '' 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 silicat ...

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 ** ...

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. ...

or river bed origin known as the

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock 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, siltston ...

from the

Jurassic The Jurassic ( ) is a geologic period and 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 Jurassic constitutes the middle period of ...

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

during the

Laramide orogeny The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the ...

. 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 d ...

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 The Fremont River is a long river in southeastern Utah, United States that flows from the Johnson Valley Reservoir, which is located on the Wasatch Plateau near Fish Lake, southeast through Capitol Reef National Park to the Muddy Creek near ...

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 Gree ...

fruits, as well as wild game, including mule deer,

bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subsp ...

, 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

trapezoid A quadrilateral with at least one pair of parallel sides is called a trapezoid () in American and Canadian English. In British and other forms of English, it is called a trapezium (). A trapezoid is necessarily a convex quadrilateral in Eu ...

al 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 bed A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätt ...

s) 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 fossi ...

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 (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...

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 ...

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 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 The Sierra Club is an environmental organization with chapters in all 50 United States, Washington D.C., and Puerto Rico. The club was founded on May 28, 1892, in San Francisco, California, by Scottish-American preservationist John Muir, who b ...

, 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 A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of ...

from western states, who were committed to the project in order to secure water rights, obtain cheap hydroelectric power and develop reservoirs as tourist destinations. After much debate, Congress settled on a compromise that eliminated

Echo Park Dam Echo Park Dam was proposed in the 1950s by the U.S. Bureau of Reclamation as a central feature of the Colorado River Storage Project. Situated on the Green River, a major tributary of the Colorado River, the dam was proposed for the Echo Park dist ...

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 The Shoshone or Shoshoni ( or ) are a Native American tribe with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshone: southern Idaho * Western Shoshone: Nevada, northern Utah * Goshute: western Utah, e ...

. :* 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 Harpers Corner view east

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 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 ''Glyptops'' (Greek for "grooved face") is an extinct genus of pleurosternid freshwater turtle known from the Late Jurassic of North America. Taxonomy The type species, ''Glyptops plicatulus'', was first described as ''Compsemys plicatulus'' by ...

plicatus'' :::''

Dinochelys ''Dinochelys'' (from Greek ''deinos'' -terrible- and ''chelys'' -turtle) is an extinct genus of paracryptodiran turtle from the Late Jurassic Morrison Formation. See also * Paleobiota of the Morrison Formation The Morrison Formation is a dist ...

whitei'' :Rhynchocephalia :::'' Opisthias rarus'' :Crocodilia ::Mesosuchia :::Gonipholididae ::::''

Goniopholis ''Goniopholis'' (meaning "angled scale") is an extinct genus of goniopholidid crocodyliform that lived in Europe and Africa during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles. It ranged fr ...

'' sp. :::Atoposauridae ::::'' Hoplosuchus kayi'' (h) ;Dinosauria :Saurischia ::Theropoda :::'' Ceratosaurus'' sp. :::'' Torvosaurus'' sp. :::'' Allosaurus fragilis'' ::Sauropoda :::''

Apatosaurus ''Apatosaurus'' (; meaning "deceptive lizard") is a genus of herbivorous sauropod dinosaur that lived in North America during the Late Jurassic period. Othniel Charles Marsh described and named the first-known species, ''A. ajax'', in 1 ...

louisae'' (h) :::''

Barosaurus ''Barosaurus'' ( ) was a giant, long-tailed, long-necked, plant-eating sauropod dinosaur closely related to the more familiar ''Diplodocus''. Remains have been found in the Morrison Formation from the Upper Jurassic Period of Utah and South Da ...

lentus'' :::''

Camarasaurus ''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 ...

lentus'' :::''

Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek δ ...

hallorum'' :::'' Uintasaurus 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

Geology

History

Fremont people

Early scientific explorations

National monument

Echo Park Dam controversy

Historic places

Climate

Features

The quarry

Fossils from Carnegie Quarry

See also

References

Further reading

External links