Cleveland Lloyd Dinosaur Quarry
Encyclopedia
The Cleveland Lloyd Dinosaur Quarry National Natural Landmark, located in The San Rafael Swell, near Cleveland, Utah
contains the densest concentration of Jurassic
dinosaur
fossils ever found. Well over 15,000 bones have been excavated from this Jurassic 'predator trap
' and there are many thousands more awaiting excavation and study. It was designated a National Natural Landmark
in October 1965.
. There is a skeleton reconstruction of an adult Allosaurus
(and other bones) on display in the visitor center, along with many other exhibits. A renovated and expanded quarry visitor center was dedicated on April 28, 2007.
led by William Lee Stokes began work. In three summers, they collected 1,200 bones. The quarry was not worked again until 1960. In 1974, a new dinosaur was discovered by James H. Madsen, Jr., Assistant Research Professor of Geology
and Geophysics
, University of Utah, making him the first person to discover a new dinosaur out of the Morrison Formation
in 75 years. He named it Stokesosaurus clevelandi. In 1979, another new dinosaur was found in the quarry by Madsen. He named it Marshosaurus bicentesimus. In 1987, Brigham Young University
paleontologists excavated a fossil dinosaur egg, at the time the oldest such egg ever found.
Over the years, excavations led by the University of Utah and the Utah Museum of Natural History
have resulted in the collection of more than 12,000 fossil bones from the quarry. While most of the original fossils are currently housed at the Utah Museum of Natural History, many skeletons reproduced from Cleveland-Lloyd dinosaur remains are now on exhibit in more than 65 museums worldwide. Original specimens from the quarry remain on public exhibit in Utah at the Utah Museum of Natural History in Salt Lake City
, the College of Eastern Utah Prehistoric Museum
in Price
and the Earth Science Museum at Brigham Young University
in Provo
.
The U.S. Department of the Interior, Bureau of Land Management
(BLM) opened a visitor center at the Cleveland-Lloyd Dinosaur Quarry in 1968. This was the first-ever BLM visitor center. On April 28, 2007 a new, larger facility was dedicated that has updated exhibits. The new visitor center generates its own electricity from rooftop solar panels.
. The fossil deposit, which is interpreted to be a possible predator trap
, consists of a calcareous smectitic mudstone
which accumulated on the floodplain of an anastomosing river system. An anastomosing river system consists of multiple interconnected channels confined by prominent levees separated by interchannel topographic lows. The depositional environment of the quarry mudstone
was an interchannel seasonal accumulation of clay nested in a topographic low between channel levees called a floodpond.
Dinosaurs became entrapped in the cohesive and adhesive mud as they drank and hunted near the floodpond. The preserved fauna consists of almost all dinosaurs with the majority being carnivorous dinosaurs including Allosaurus
(material from at least 44 individuals make up almost 67% of all remains), Torvosaurus
(1), Ceratosaurus
(1), Stokesosaurus
(2), Marshosaurus
(2), and possibly an Ornitholestes
. Herbivorous dinosaurs include Camarasaurus
(5), Haplocanthosaurus
(1), Barosaurus
(1), Amphicoelias
(1), Mongolosaurus
(1), an unidentified sauropod, Camptosaurus
(5), Stegosaurus
(4), a possible ankylosaur (1), and an unidentified ornithopod. Non-dinosaurian fauna include a crocodile (Goniopholis), 2 turtles (Glyptops), 4 genera of gastropoda (snails), and 4 genera of charophyte.
The atypical predator/prey ratio (3:1) represented at the quarry may be explained by pack hunting tendencies of Allosaurus
. The high percentage of smaller individual allosaurs suggests that juveniles coordinated their efforts to capture and kill prey. They may have followed their prey into the floodpond and subsequently became mired themselves. The close spatial proximity of skull elements (most belonging to Allosaurus) supports this hypothesis. Larger individual theropods almost certainly became mired while attempting to scavenge the carcasses of other entrapped dinosaurs (Richmond and Morris, 1996).
Cleveland, Utah
Cleveland is a town in Emery County, Utah, in the United States. As of the 2000 census, the town population was 508.-Geography:Cleveland is located at ....
contains the densest concentration of Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
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 ever found. Well over 15,000 bones have been excavated from this Jurassic 'predator trap
Predator trap
A predator trap is a natural hazard such as a tar pit. Predators would become attracted to struggling animals that have become entrapped in viscous or glutinous material, such as a heavy sedimentary deposit or tar and, in the process, become entrapped themselves...
' and there are many thousands more awaiting excavation and study. It was designated a National Natural Landmark
National Natural Landmark
The National Natural Landmark program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only natural areas program of national scope that identifies and recognizes the best examples of biological and geological features in...
in October 1965.
Visiting
The visitor center is administered by the Bureau of Land ManagementBureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...
. There is a skeleton reconstruction of an adult Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
(and other bones) on display in the visitor center, along with many other exhibits. A renovated and expanded quarry visitor center was dedicated on April 28, 2007.
History
The quarry was probably found by sheepmen and cowmen as they drove their animals through the area during the late 19th century. In 1927, the Department of Geology at the University of Utah, under the direction of Chairman F.F. Hintze, visited the area and collected 800 bones. In 1939, a field party from Princeton UniversityPrinceton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
led by William Lee Stokes began work. In three summers, they collected 1,200 bones. The quarry was not worked again until 1960. In 1974, a new dinosaur was discovered by James H. Madsen, Jr., Assistant Research Professor of Geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
and Geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
, University of Utah, making him the first person to discover a new dinosaur out of the Morrison Formation
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...
in 75 years. He named it Stokesosaurus clevelandi. In 1979, another new dinosaur was found in the quarry by Madsen. He named it Marshosaurus bicentesimus. In 1987, Brigham Young University
Brigham Young University
Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
paleontologists excavated a fossil dinosaur egg, at the time the oldest such egg ever found.
Over the years, excavations led by the University of Utah and the Utah Museum of Natural History
Utah Museum of Natural History
The Natural History Museum of Utah is a museum located at the Rio Tinto Center on the campus of the University of Utah in Salt Lake City, Utah, United States. The museum shows exhibits of natural history subjects, specifically about Utah's natural history...
have resulted in the collection of more than 12,000 fossil bones from the quarry. While most of the original fossils are currently housed at the Utah Museum of Natural History, many skeletons reproduced from Cleveland-Lloyd dinosaur remains are now on exhibit in more than 65 museums worldwide. Original specimens from the quarry remain on public exhibit in Utah at the Utah Museum of Natural History in Salt Lake City
Salt Lake City, Utah
Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...
, the College of Eastern Utah Prehistoric Museum
College of Eastern Utah Prehistoric Museum
The USU Eastern Prehistoric Museum, formerly known as the College of Eastern Utah Prehistoric Museum, is a museum accredited by the American Association of Museums located in Price, Utah. The museum seeks to promote public understanding of prehistory through interpretive exhibits, educational...
in Price
Price, Utah
Price is a city in Carbon County, Utah, United States. The city is home to the USU-College of Eastern Utah, as well as the large USU Eastern Prehistoric Museum affiliated with the college. Price is located within short distances from both Nine Mile Canyon and the Manti-La Sal National Forest...
and the Earth Science Museum at Brigham Young University
Brigham Young University
Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
in Provo
Provo, Utah
Provo is the third largest city in the U.S. state of Utah, located about south of Salt Lake City along the Wasatch Front. Provo is the county seat of Utah County and lies between the cities of Orem to the north and Springville to the south...
.
The U.S. Department of the Interior, Bureau of Land Management
Bureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...
(BLM) opened a visitor center at the Cleveland-Lloyd Dinosaur Quarry in 1968. This was the first-ever BLM visitor center. On April 28, 2007 a new, larger facility was dedicated that has updated exhibits. The new visitor center generates its own electricity from rooftop solar panels.
Geology
The Cleveland-Lloyd Dinosaur Quarry of east central Utah has produced one of the most prolific dinosaurs bone assemblages in the Upper Jurassic beds of North America. The quarry is part of the Brushy Basin Member of the Morrison FormationMorrison 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...
. The fossil deposit, which is interpreted to be a possible predator trap
Predator trap
A predator trap is a natural hazard such as a tar pit. Predators would become attracted to struggling animals that have become entrapped in viscous or glutinous material, such as a heavy sedimentary deposit or tar and, in the process, become entrapped themselves...
, consists of a calcareous smectitic mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
which accumulated on the floodplain of an anastomosing river system. An anastomosing river system consists of multiple interconnected channels confined by prominent levees separated by interchannel topographic lows. The depositional environment of the quarry mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
was an interchannel seasonal accumulation of clay nested in a topographic low between channel levees called a floodpond.
Dinosaurs became entrapped in the cohesive and adhesive mud as they drank and hunted near the floodpond. The preserved fauna consists of almost all dinosaurs with the majority being carnivorous dinosaurs including Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
(material from at least 44 individuals make up almost 67% of all remains), Torvosaurus
Torvosaurus
Torvosaurus is a genus of large theropod dinosaur that lived during the Late Jurassic period...
(1), Ceratosaurus
Ceratosaurus
Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...
(1), Stokesosaurus
Stokesosaurus
Stokesosaurus is a genus of small , early tyrannosaur from the Late Jurassic period of Utah and England. It was named after Utah geologist William Lee Stokes...
(2), Marshosaurus
Marshosaurus
Marshosaurus was a genus of medium sized theropod, with a size up to 5 or 6 meters in length and a skull about 60 cm long. It is known from parts of at least three individuals from the Morrison Formation of Utah and Colorado.The holotype is a left ilium, or upper pelvis bone found at the...
(2), and possibly an Ornitholestes
Ornitholestes
Ornitholestes was a small theropod dinosaur of the late Jurassic of Western Laurasia . To date, it is known only from a single partial skeleton, and badly crushed skull found at the Bone Cabin Quarry near Medicine Bow, Wyoming, in 1900...
. Herbivorous dinosaurs include Camarasaurus
Camarasaurus
Camarasaurus meaning 'chambered lizard', referring to the hollow chambers in its vertebrae was a genus of quadrupedal, herbivorous dinosaurs. It was the most common of the giant sauropods to be found in North America...
(5), Haplocanthosaurus
Haplocanthosaurus
Haplocanthosaurus is a genus of sauropod dinosaur. Two species, H. delfsi and H. priscus, are known from incomplete fossil skeletons. It lived during the late Jurassic period , 155 to 152 million years ago. The type species is H. priscus, and the referred species H...
(1), Barosaurus
Barosaurus
Barosaurus ; Greek barys/βαρυς meaning 'heavy' and saurus/σαυρος meaning 'lizard', 'heavy lizard') was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus...
(1), Amphicoelias
Amphicoelias
Amphicoelias is a genus of herbivorous sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A. fragillimus may have been the longest known vertebrate at in length, and may have had a mass of up...
(1), Mongolosaurus
Mongolosaurus
Mongolosaurus is a genus of sauropod dinosaur which lived during the Early Cretaceous of China.In 1928 a team from the American Museum of Natural History, headed by Roy Chapman Andrews, at On Gong Gol near Hukongwulong in Inner Mongolia, in Quarry 714 discovered a sauropod tooth. In 1933 Charles W...
(1), an unidentified sauropod, Camptosaurus
Camptosaurus
Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America. The name means 'flexible lizard', ....
(5), Stegosaurus
Stegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
(4), a possible ankylosaur (1), and an unidentified ornithopod. Non-dinosaurian fauna include a crocodile (Goniopholis), 2 turtles (Glyptops), 4 genera of gastropoda (snails), and 4 genera of charophyte.
The atypical predator/prey ratio (3:1) represented at the quarry may be explained by pack hunting tendencies of Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
. The high percentage of smaller individual allosaurs suggests that juveniles coordinated their efforts to capture and kill prey. They may have followed their prey into the floodpond and subsequently became mired themselves. The close spatial proximity of skull elements (most belonging to Allosaurus) supports this hypothesis. Larger individual theropods almost certainly became mired while attempting to scavenge the carcasses of other entrapped dinosaurs (Richmond and Morris, 1996).
Paleofauna
Fossil taxa discovered at the Cleveland-Lloyd site include:- Plantae
- Thallophyta
- Aclistochara
- Latochara
- Stellatochara
- Thallophyta
- Animalia
- MolluscaMolluscaThe Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
- GastropodaGastropodaThe Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...
- Amplovalvata
- Amplovoluta
- Valvata
- Viviparus
- Gastropoda
- Chordata
- Chelonia
- Glyptops
- Chelonia
- Mollusca
| Theropods reported from the Cleveland-Lloyd Quarry | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Amount | Notes | Images | ||
Marshosaurus Marshosaurus Marshosaurus was a genus of medium sized theropod, with a size up to 5 or 6 meters in length and a skull about 60 cm long. It is known from parts of at least three individuals from the Morrison Formation of Utah and Colorado.The holotype is a left ilium, or upper pelvis bone found at the... |
M. bicentesimus |
2 |
A small 20 ft (6m) megalosaurid. |
|||
Torvosaurus Torvosaurus Torvosaurus is a genus of large theropod dinosaur that lived during the Late Jurassic period... |
T. tanneri |
1 |
The second laregest theropod reported from the Quarry. |
 |
||
Stokesosaurus Stokesosaurus Stokesosaurus is a genus of small , early tyrannosaur from the Late Jurassic period of Utah and England. It was named after Utah geologist William Lee Stokes... |
S. clevelandi |
3 |
The largest coelurosaur found |
|||
Ornitholestes Ornitholestes Ornitholestes was a small theropod dinosaur of the late Jurassic of Western Laurasia . To date, it is known only from a single partial skeleton, and badly crushed skull found at the Bone Cabin Quarry near Medicine Bow, Wyoming, in 1900... |
Indeterminate |
1 |
- |
|||
Allosaurus Allosaurus Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros... |
A. fragilis |
44 - 60 |
The largest theropod found |
 |
||
Ceratosaurus Ceratosaurus Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal... |
C. nasicornis |
1 |
The rarest theropod species in the quarry |
|||
| Sauropods reported from the Cleveland-Lloyd Quarry | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Notes | Images | |||
Camarasaurus Camarasaurus Camarasaurus meaning 'chambered lizard', referring to the hollow chambers in its vertebrae was a genus of quadrupedal, herbivorous dinosaurs. It was the most common of the giant sauropods to be found in North America... |
C. lentus |
3 skeletons were unearthed |
 |
|||
Barosaurus Barosaurus Barosaurus ; Greek barys/βαρυς meaning 'heavy' and saurus/σαυρος meaning 'lizard', 'heavy lizard') was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus... |
B.lentus |
- |
||||
Amphicoelias Amphicoelias Amphicoelias is a genus of herbivorous sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A. fragillimus may have been the longest known vertebrate at in length, and may have had a mass of up... |
A.altus |
A smaller cousin of A.fragilimus |
- |
|||
Mongolosaurus Mongolosaurus Mongolosaurus is a genus of sauropod dinosaur which lived during the Early Cretaceous of China.In 1928 a team from the American Museum of Natural History, headed by Roy Chapman Andrews, at On Gong Gol near Hukongwulong in Inner Mongolia, in Quarry 714 discovered a sauropod tooth. In 1933 Charles W... |
cf Indeterminate |
- |
- |
|||
Brachiosaurus Brachiosaurus Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,... |
B.althithorax |
The largest 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... reported |
 |
|||
Haplocanthosaurus Haplocanthosaurus Haplocanthosaurus is a genus of sauropod dinosaur. Two species, H. delfsi and H. priscus, are known from incomplete fossil skeletons. It lived during the late Jurassic period , 155 to 152 million years ago. The type species is H. priscus, and the referred species H... |
H.priscus |
The last Cetiosauridae |
- |
|||
| Ornithischians reported from the Cleveland-Lloyd Quarry | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Notes | Images | |||
Camptosaurus Camptosaurus Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America. The name means 'flexible lizard', .... |
C.dispar |
- |
- |
|||
Stegosaurus Stegosaurus Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well... |
S.stenops |
The largest ornithischian of its time. |
 |
|||
See also
- La Brea tar pitsLa Brea Tar PitsThe La Brea Tar Pits are a cluster of tar pits around which Hancock Park was formed, in the urban heart of Los Angeles. Asphaltum or tar has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with water...
- List of dinosaur-bearing rock formations
- Predator trapPredator trapA predator trap is a natural hazard such as a tar pit. Predators would become attracted to struggling animals that have become entrapped in viscous or glutinous material, such as a heavy sedimentary deposit or tar and, in the process, become entrapped themselves...