Como Bluff

Como Bluff is a long ridge extending east–west, located between the towns of Rock River and Medicine Bow, Wyoming. The ridge is an anticline, formed as a result of compressional geological folding. Three geological formations, the Sundance, the Morrison, and the Cloverly Formations, containing fossil remains from the Late Jurassic of the Mesozoic Era are exposed.

Nineteenth-century paleontologists discovered many well-preserved specimens of dinosaurs, as well as mammals, turtles, crocodilians, and fish from the Morrison Formation. Because of this, Como Bluff is considered to be one of the major sites for the early discovery of dinosaur remains. Among the species discovered is the only known specimen of Coelurus. Significant discoveries were made in 22 different areas scattered along the entire length of the ridge. It is included on the National Register of Historic Places as well as the National Natural Landmark list.

History of discovery


The discovery of dinosaurs at Como Bluff has been recounted numerous times, most notably by Schuchert and LeVene, Shur, Ostrom and McIntosh, and Jaffe. Most of the specimens were collected by men working for O.C. Marsh between 1877 and 1889, although some were collected by the Hubbel brothers for E.D. Cope between 1879 and 1880. The American Museum of Natural History (AMNH) excavated in 1897 -1898, finding two partial skeletons of sauropods. A summary of the quarries and their contents is given below.

In later years, the American Museum of Natural History and Yale University jointly reopened Quarry 9, the Mammal Quarry, 1968–1970, finding only a few specimens. More recently, Robert Bakker has done some collecting there with a variety of groups.

In addition to the major significance of dinosaur discoveries at Como Bluff, the site has also been the source of significant early mammal fossils. In early 1878, Marsh was ecstatic to find that one of his men had uncovered a fossil from a Jurassic mammal. Within a year, the historic Quarry 9 at Como was discovered, producing an astounding 250 specimens, which increased the knowledge of Jurassic mammals exponentially.

Como Bluff historical quarries (pre-1900)
Data source:. . . (h)= holotype

AMNH Quarries
Excavated by the American Museum of Natural History

AMNH Quarry 1

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Diplodocus sp

AMNH Quarry 2

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Brontosaurus excelsus
 * Camarasaurus sp,

AMNH localities unknown
(some could be from Quarry 1 or 2)
 * Reptilia
 * Testudines
 * Amphichelydia
 * Glyptops plicatus
 * Squamata
 * ?Sauria indeterminant
 * Lacertilia
 * Paramacellodus sp.
 * Choristodera
 * Cteniogenys antiquus
 * Crocodilia
 * Mesosuchia
 * Goniopholis sp.

Brown's Quarry A

 * Dinosauria
 * Ornithischia
 * Stegosauria
 * Stegosaurus sp.

Brown's Quarry B

 * Dinosauria
 * Ornithischia
 * Stegosauria
 * Stegosaurus sp.

Brown's Quarry C

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus fragilis

Brown's Quarry D

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus fragilis

Brown's Quarry G

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Camarasaurus sp.

Arthur Lakes Quarry 1A. (Big Canyon Quarry)
Excavated by Arthur Lakes.
 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus sp.
 * Sauropoda
 * Camarasaurus sp.
 * Ornithischia
 * Ornithopoda
 * Camptosaurus amplus (h) (now Allosaurus sp.)

E.D. Cope's Quarries
Excavated by Edward Drinker Cope

Cope's Quarry 3

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus sp.

Cope's Quarry 4

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus sp.
 * Ornithischia
 * Stegosauria
 * Stegosaurus sp.

Cope's Quarry 5

 * Reptilia
 * Pterosauria
 * Dermodactylus montanus


 * Dinosauria
 * Saurischia
 * Sauropoda
 * Apatosaurus sp.

Cope's localities unknown
(could be from Quarry 1, 2)
 * Reptilia
 * Testudines
 * Amphichelydia
 * Dinochelys sp.
 * Glyptops plicatus
 * Crocodilia
 * Mesosuchia
 * Goniopholis sp.


 * Dinosauria
 * Ornithischia
 * Ornithopoda
 * ?Camptosaurus sp.
 * Stegosauria
 * Stegosaurus sp.


 * Mammalia
 * genus and species indeterminant

William Harlow Reed's Quarries
Excavated by William Harlow Reed.

Reed's Quarry 1

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus atrox (h) (now Allosaurus fragilis)
 * Sauropoda
 * Camarasaurus grandis (h)
 * Camarasaurus impar (h) (now Camarasaurus grandis)
 * Camarasaurus robustus (h) (now Camarasaurus grandis)
 * Pleurocoelus montanus (h) (now Camarasaurus grandis)
 * Diplodocus sp.


 * Mammalia
 * genus and species indeterminant

Reed's Quarry 1 ½

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus fragilis
 * Sauropoda
 * genus and species indeterminant

Reed's Quarry 2

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Apatosaurus sp.

Reed's Quarry 3

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus lucaris (h) (now Allosaurus sp.)
 * Sauropoda
 * Camarasaurus grandis
 * Ornithischia
 * Ornithopoda
 * Dryosaurus sp.
 * Stegosauria
 * Stegosaurus sp.

Reed's Quarry 4

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus fragilis
 * Sauropoda
 * Apatosaurus sp.
 * Barosaurus sp.
 * Camarasaurus sp.
 * Ornithischia
 * Stegosauria
 * Stegosaurus sp.

Reed's Quarry 5

 * Reptilia
 * Pterosauria
 * Dermodactylus montanus (h) (now nomen dubium)


 * Dinosauria
 * Saurischia
 * Sauropoda
 * Diplodocus sp.
 * Ornithischia
 * Ornithopoda
 * Dryosaurus altus (h)

Reed's Quarry 6

 * Reptilia
 * Crocodylia
 * Mesosuchia
 * Goniopholis sp.

Reed's Quarry 7 (Three Trees Quarry)

 * Dinosauria
 * Ornithischia
 * Ornithopoda
 * Laosaurus consors (h) (now Othnielosaurus consors)

Reed's Quarry 8

 * Reptilia
 * Testudines
 * genus and species indeterminant
 * Crocodilia
 * Mesosuchia
 * Goniopholis sp.


 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus sp.
 * Coelurus fragilis
 * Sauropoda
 * Camarasaurus sp.
 * Diplodocus sp.
 * Ornithischia
 * Stegosauria
 * Stegosaurus sp.

Reed's Quarry 9 (Mammal Quarry)

 * Osteichthyes
 * Actinopterygii
 * genus and species indeterminant
 * Amiiformes
 * Ophiopsis sp.
 * Sarcopterygii
 * Dipnoi
 * Ceratodus guentheri


 * Amphibia
 * Anura
 * Comobatrachus aenigmatis
 * Discoglossoidea
 * Enneabatrachus hechti
 * Pelobatidae indeterminant
 * Pipoidea?
 * Eobatrachus agilis (h)
 * Caudata
 * genus and species indeterminant
 * Comonecturoides marshi (h)


 * Reptilia
 * Testudines
 * Amphichelydia
 * Dinochelys whitei
 * Glyptops ornatus
 * Squamata
 * ?Sauria indeterminant
 * Lacertilia
 * Dorsetisaurus sp.
 * Paramacellodus sp.
 * Rhynchocephalia
 * Opisthias rarus (h)
 * Theretairus antiquus (h)
 * Choristodera
 * Cteniogenys antiquus (h)
 * Crocodylia
 * Sphenosuchia
 * Macelognathus vagans (h)
 * Mesosuchia
 * Goniopholis sp.


 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus fragilis
 * Ceratosaurus nasicornis
 * Coelurus fragilis
 * Ornitholestes hermanni?
 * Tyrannosauroidea
 * Stokesosaurus clevelandi?
 * Sauropoda
 * Macronaria indeterminant
 * Diplodocidae indeterminant
 * Ornithischia
 * Ornithopoda
 * Othnielosaurus consors
 * Dryosaurus sp.
 * Camptosaurus sp.
 * Stegosauria
 * Stegosaurus sp.
 * Pterosauria
 * Rhamphorhynchoidea
 * Laopteryx priscus (h) (now nomen dubium)


 * Mammalia
 * Docodonta
 * Docodontidae
 * Docodon affinis (h)
 * Docodon crassus (h)
 * Docodon striatus (h)
 * Docodon superus (h)
 * Docodon victor (h)
 * Multituberculata
 * Allodontidae
 * Ctenacodon laticeps (h)
 * Ctenacodon scindens (h)
 * Ctenacodon serratus (h)
 * Psalodon fortis (h)
 * Psalodon potens (h)
 * ?Psalodon marshi (h)
 * Triconodonta
 * Amphilestidae
 * Aploconodon comoensis (h)
 * Comodon gidleyi (h)
 * Triconodontidae
 * Priacodon ferox (h)
 * Priacodon grandaevus (h)
 * Priacodon lulli (h)
 * Priacodon robustus (h)
 * Trioracodon bisulcus (h)
 * Symmetrodonta
 * Amphidontidae
 * Amphidon superstes (h)
 * Tinodontidae
 * Tinodon bellus (h)
 * Eurylambda aequicrurius
 * Dryolestida
 * Dryolestidae
 * Amblotherium gracilis (h)
 * Dryolestes priscus
 * Dryolestes obtusus (h)
 * Dryolestes vorax (h)
 * Laolestes eminens (h)
 * Laolestes (Melanodon) goodrichi (h)
 * Laolestes (Melanodon) oweni (h)
 * Miccylotyrans minimus (h)
 * Paurodontidae
 * Araeodon intermissus (h)
 * Archaeotrigon brevimaxillus (h)
 * Archaeotrigon distagmus (h)
 * Comotherium richi (h)
 * Euthlastus cordiformis (h)
 * Paurodon valens (h)
 * Tathiodon agilis (h)

Reed's Quarry 10

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Brontosaurus excelsus (h)

Reed's Quarry 11

 * Dinosauria
 * Saurischia
 * Sauropoda
 * Apatosaurus amplus (h) (now Brontosaurus excelsus)
 * Ornithischia
 * Stegosauria
 * Stegosaurus duplex (h) (now Stegosaurus ungulatus)


 * Mammalia
 * genus and species indeterminant

Reed's Quarry 12 (Robbers' Roost Quarry)

 * Reptilia
 * Testudines
 * genus and species indeterminant
 * Crocodylia
 * Mesosuchia
 * Goniopholis sp.


 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus sp.
 * Torvosaurus tanneri
 * Coelurus sp.
 * Fosterovenator churei
 * Sauropoda
 * Camarasaurus sp.
 * Diplodocus sp.
 * Ornithischia
 * ornithopoda
 * genus and species indeterminant
 * Stegosauria
 * Stegosaurus ungulatus (h)

Reed's Quarry 13

 * Reptilia
 * Testudines
 * Amphichelydia
 * Glyptops plicatulus
 * Crocodylia
 * Mesosuchia
 * Goniopholis sp.


 * Dinosauria
 * Saurischia
 * Theropoda
 * Coelurus agilis (h) (part of Coelurus fragilis holotype)
 * Coelurus fragilis (h)
 * Saurischia
 * Sauropoda
 * ?Brachiosaurus sp.
 * Camarasaurus lentus (h)
 * Diplodocus sp.
 * Ornithischia
 * Ornithopoda
 * Camptonotus dispar (h) (now Camptosaurus dispar)
 * Camptosaurus medius (h)
 * Camptosaurus nanus (h)
 * Camptosaurus browni (h)
 * Dryosaurus sp.
 * Stegosauria
 * Diracodon laticeps (h) (now Stegosaurus sp.)
 * Stegosaurus sulcatus (h)
 * Stegosaurus stenops
 * Stegosaurus ungulatus

Reed Quarry 14

 * Dinosauria
 * Saurischia
 * Theropoda
 * Allosaurus ferox (h) (now Allosaurus fragilis)