Hell Creek Formation

Hell Creek Formation Stratigraphic range: Maastrichtian, 66.8–65.5 Ma PreЄ Є O S D C P T J K Pg N ↓
Exposure in the badlands in the vicinity of Ft. Peck Reservoir
Type	Geological formation
Overlies	Fox Hills Formation
Location
Country	USA

The Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation spans about 1.3 million years, terminating at the K-Pg boundary, dated to 65.5 million years ago.^[1]

The Hell Creek Formation occurs in Montana and portions of North Dakota, South Dakota, and Wyoming. In Montana, the Hell Creek Formation overlies the Fox Hills Formation and is the uppermost formation of the Cretaceous period. "Pompey's Pillar" at the Pompeys Pillar National Monument is a small isolated section of the Hell Creek Formation.

It is a series of fresh and brackish-water clays, mudstones, and sandstones deposited during the Maastrichtian, the last part of the Cretaceous period, by fluvial activity in fluctuating river channels and deltas and very occasional peaty swamp deposits along the low-lying eastern continental margin fronting the late Cretaceous Western Interior Seaway. The climate was mild, and the presence of crocodilians suggests a sub-tropical climate, with no prolonged annual cold. The famous iridium-enriched K–Pg boundary, which separates the Cretaceous from the Cenozoic, occurs as a discontinuous but distinct thin marker bedding within the Formation, near its uppermost strata.

The world's largest collection of Hell Creek fossils is housed and exhibited at the Museum of the Rockies, in Bozeman, Montana. The specimens displayed are the result of the museum's Hell Creek Project, a joint effort between the museum, Montana State University, the University of California, Berkeley, the University of North Dakota and the University of North Carolina which began in 1998. The formation is also a popular location for commercial excavations.

Paleobiota

The formation has produced impressive assemblages of invertebrates, plants, mammals, fish, reptiles, and amphibians. Notable dinosaur finds include Tyrannosaurus and Triceratops. The most complete Hadrosaurid dinosaur ever found was retrieved in 2000 from the Hell Creek Formation and widely publicised in a National Geographic documentary aired in December 2007. A few bird, mammal, and pterosaur fossils have also been found. Teeth of sharks and rays are sometimes found in the riverine Hell Creek Formation, suggesting that some of these taxa were tolerant of fresh water then as now.

Amphibians

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Amphibians reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Barbourula^[2]	Indeterminate^[3]	Montana^[4]
Eopelobates^[5]	Indeterminate^[3]	Montana^[4]
Habrosaurus^[3]	H. dilatus^[3]	Montana^[4]
Lisserpeton^[3]	L. bairdi^[3]	Montana^[4]
Opisthotriton^[3]	O. kayi^[3]	Montana^[4]
Proamphiuma^[3]	P. cretacica^[3]	Montana^[4]
Prodesmodon^[3]	P. copei^[3]	Montana^[4]
Scapherpeton^[3]	S. tectum^[3]	Montana^[4]
Scotiophryne^[3]	S. pustulosa^[3]	Montana^[4]

Bony fishes

Bony fishes reported from the Hell Creek Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Acipenser^[6]	A. eruciferus^[6]	Montana^[7]
Amia^[6]	A. fragosa^[6]	Montana^[7]
Belonostomus^[6]	B. longirostris^[6]	Montana^[7]
Coriops^[8]	C. amnicolus^[8]	Montana^[9]
Lepisosteus^[6]	L. occidentalis^[6]	Montana^[7]
Palaeolabrus^[6]	P. montanensis^[6]	Montana^[7]
Paleopsephurus^[6]	P. wilsoni^[6]	Montana^[7]
Paralbula^[10]	P. casei^[10]	Montana^[9]
Platacodon^[8]	P. nanus^[8]	Montana^[9]
Protamia^[6]	Indeterminate^[6]	Montana^[7]
Protoscaphirhynchus^[6]	P. squamosus^[6]	Montana^[7]

Cartilaginous fishes

Cartilaginous fishes reported from the Hell Creek Formation
Genus	Species	Location	Stratigraphic position	Material	Notes
Ischyrhiza^[11]	I. avonicola^[11]	Montana^[12]
Lonchidion^[11]	L. selachos^[11]	Montana^[12]
Myledaphus^[11]	M. bipartitus^[11]	Montana^[12]

Ornithischians

Ankylosaurs

Ankylosaurs reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Ankylosaurus^[13]	Ankylosaurus magniventris^[13]	Montana^[13]			An ankylosaur. Also found in the Lance and Scollard Formations.
?Edmontonia^[13]	Unnamed and indeterminate remains^[13]	Montana^[13] North Dakota^[14] South Dakota^[15]			An ankylosaur.

Ceratopsians

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Ceratopsians reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Leptoceratops^[13]	Indeterminate^[16]	Montana^[13]			A small primitive-looking ceratopsian.
?Tatankaceratops	?T. sacrisonorum	South Dakota			A ceratopsian possibly synonymous with Triceratops^[17]
?Torosaurus^[13]	?T. latus^[13]	Montana^[13] North Dakota^[14] South Dakota^[15]			A ceratopsian possibly synonymous with Triceratops.^[18] Also found in the Frenchman and Lance Formations.
Triceratops^[13]	T. horridus^[13]	Montana^[13] North Dakota^[14] South Dakota^[15]		Very common.	A ceratopsian, very common. Also found in the Evanston, Frenchman, Kirtland, Lance, Laramie, and Scollard Formations.
	T. maximus^[13]	Montana^[13]		"[Eight] vertebrae, [two] ribs."^[19]	Later found to be indeterminate ceratopsid remains.^[13]
	T. prorsus^[13]	Montana^[13]		Very common.	Also found in the Frenchman and Lance Formations.
	T. serratus^[13]	Montana^[13]			Later referred to T. horridus.^[13]

Ornithopods

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Ornithopods reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Anatosaurus	A. annectens				Reclassified as Edmontosaurus annectens^[20]
Anatotitan	A. copei				Junior synonym of Edmontosaurus annectens.^[20]
Bugenasaura	B. garbanii				Junior synonym of Thescelosaurus garbanii
Bugenasaura	B. infernalis				Reclassified as Thescelosaurus
Diclonius	D. mirabilis				Junior synonym of Trachodon mirabilis, remains actually belong to E. annectens^[20]
Edmontosaurus	E. annectens	Montana^[13] South Dakota^[15]		Very common.	A hadrosaur. Also found in the Denver, Frenchman, Lance, Laramie, and Scollard Formations.
Edmontosaurus	E. regalis				Common hadrosaur remains are often referred to this genus, but all fossils diagnosable as E. regalis specifically are only known from older deposits.^[21]
Parasaurolophus^[22]	P. walkeri^[22]	Montana^[13]			A possible lambeosaurine hadrosaur potentially similar to the Campanian genus Parasaurolophus
Thescelosaurus^[15]	?T. garbanii^[23]	Montana^[23] South Dakota^[24]
	T. infernalis				Nomen dubium
	T. neglectus^[15]	South Dakota^[15]			A small ornithopod. Also found in the Frenchman, Lance, Laramie, and Scollard Formations.^[25] Sometimes misspelled as T. garbani.^[23]
	Indeterminate^[26]	North Dakota^[14]
Trachodon	T. mirabilis				Misclassified, remains now referred to Edmontosaurus annectens

Pachycephalosaurs

An undescribed Pachycephalosaur is present in North Dakota.^[14]

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Pachycephalosaurs reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
?Dracorex^[27]	?D. hogwartsia^[27]	South Dakota^[27]	Middle^[27]		A pachycephalosaur, possibly synonymous with Pachycephalosaurus.
Pachycephalosaurus^[13]	P. wyomingensis^[13]	Montana^[13] South Dakota^[15]			A pachycephalosaur. Also found in the Judith River and Lance Formations.
Sphaerotholus^[13]	S. buchholtzae^[13]	Montana^[13]		"Skull material."^[28]	A pachycephalosaur, possibly synonymous with Prenocephale. Also found in the Kirtland Formation
Sphaerotholus^[13]	S. goodwini^[13]	Montana^[13]		"Skull material."^[28]
Stegoceras^[13]	S. edmontonense^[13]				Pachycephalosaurid remains from Montana and south Dakota have been erroneously referred to this Campanian species.
?Stygimoloch^[13]	?S. spinifer^[13]	Montana^[13]			A pachycephalosaur, possibly synonymous with Pachycephalosaurus. Also found in the Lance Formation.
?Stygimoloch^[13]	Indeterminate^[15]	South Dakota^[15]

Plants

Plants of the Hell Creek Formation
Genus	Species	Presence	Description	Images
Metasequoia	Indeterminate		Casts of Dawn Redwood seed cones are known from the Hell Creek.
Cobbania	C. corrugata		A prehistoric species of water lettuce, previously assigned to the genus Pistia.
Araucaria	A. araucana		Casts of Monkey-puzzle leaves are found in Hell Creek.

Pterosaurs

Pterosaurs of the Hell Creek Formation
Taxa	Species	Location	Description	Images
Quetzalcoatlus^[29]	Indeterminate^[30]	Montana^[30]	A single azhdarchid neck bone may belong to the genus Quetzalcoatlus.^[30]

Theropods

Theropod tracks have been found in South Dakota.^[15] An unnamed alvarezsaurid is known from Montana.^[31]

Ornithomimosaurs

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Ornithomimids reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
"Orcomimus"	Nomen nudum	South Dakota^[32]			An ornithomimid.
Ornithomimus^[13]	Indeterminate^[13]	Montana^[13] North Dakota^[33] South Dakota^[15]			An ornithomimid
Struthiomimus^[15]	S. sedens^[34]				A large ornithomimid.^[34]
Struthiomimus^[15]	Indeterminate^[15]	North Dakota^[35] South Dakota^[15]

Oviraptorosaurs

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Oviraptorosaurs reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Caenagnathus^[15]	C. collinsi^[15]	South Dakota^[15]			Sometimes considered a junior synonym of Chirostenotes, but type material actually from the Dinosaur Park Formation
Caenagnathus^[15]	Indeterminate^[15]	South Dakota^[15]		Known from the articular region of a lower jaw catalogued as BHM 2033.^[36]
Chirostenotes^[13]	C. elegans^[13]	Montana^[13]		Partial foot catalogued as MOR 752.^[36]	A large oviraptorosaur, also found in the Dinosaur Park and Two Medicine Formations.
Chirostenotes^[13]	C. sp.	South Dakota		Based on the undescribed "Triebold specimen"
Elmisaurus	E. elegans^[13]				Junior synonym of Chirostenotes elegans.

Eumaniraptorans

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Eumaniraptorans reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Avisaurus^[13]	A. archibaldi^[13]	Montana^[13]		Two adult and one juvenile specimens, all based on lower leg elements.	An enantiornithine.
?Dromaeosaurus^[13]	Indeterminate^[13]	Montana^[13] South Dakota^[15]		Teeth	Dromaeosaurid teeth similar to the older Dromaeosaurus albertensis
Paronychodon^[13]	P. lacustris^[13]	Montana^[13] North Dakota^[14] South Dakota^[15]		Teeth	Indeterminate troodontid,^[13] actually from the Dinosaur Park, Frenchman, Judith River, Kirtland and Milk River Formations but absent in the Hell Creek.
Paronychodon^[13]	Indeterminate	South Dakota		Teeth	Indeterminate troodontid
Richardoestesia^[37]	R.? isosceles	Montana North Dakota South Dakota		Teeth
	R. cf. gilmorei	North Dakota		Teeth
	Indeterminate	South Dakota		Teeth
Saurornithoides^[38]	Indeterminate.^[13]	Montana^[13]		Teeth	Remains tentatively attributed to the Mongolian genus Saurornithoides were later referred to Troodon.^[13]
?Saurornitholestes^[14]	Indeterminate^[14]	Montana North Dakota^[14] South Dakota^[15]		Teeth, partial dentary	Dromaeosaurid remains similar to the older Saurornitholestes langstoni
Stenonychosaurus^[13]	S. inequalis^[13]	Montana^[13]			Junior synonym of Troodon formosus.^[13]
?Troodon^[13]	?T. formosus^[13]	Montana^[13]		Teeth	A troodontid, actually an indeterminate species of Troodon
?Troodon^[13]	Indeterminate^[15]	Montana South Dakota^[15]		Teeth	Troodontid teeth similar to the older Troodon formosus
Velociraptor	Indeterminate	Montana		Teeth, partial dentary	Remains tentatively attributed to the Mongolian genus Velociraptor were later tentatively referred to Saurornitholestes.
"Unnamed ornithurine B"^[1]	Indeterminate^[39]	Montana^[40]		Partial coracoid	An ornithurine possibly similar to Cimolopteryx^[39]^[1]
"Unnamed ornithurine C"^[1]	Indeterminate			Partial coracoid	An ornithurine, also present in the Fort Union Formation, the only individual bird species known to have survived the K-Pg extinction^[1]
"Unnamed ornithurine D"^[1]	Indeterminate			Partial coracoid	An ornithurine^[1]
"Unnamed hesperornithiform A"^[1]	Indeterminate			Tarsometatarsus	A primitive hesperornithiform^[1]

Tyrannosaurids

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Tyrannosaurids reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes	Images
Albertosaurus	A. lancensis	Montana			Remains later referred to Nanotyrannus lancensis.
Albertosaurus	A. "megagracilis"^[13]	Montana^[13]			Nomen nudum, remains later referred to Tyrannosaurus rex.^[13]
Aublysodon^[13]	A. mirandus^[13]	Montana^[13]			Now considered indeterminate tyrannosauroid remains.^[13]
Aublysodon^[13]	A. molnari^[13]	Montana^[13]			Remains later referred to Tyrannosaurus rex.^[13]
Deinodon	D. lancensis	Montana			Remains later referred to Nanotyrannus lancensis.
Dinotyrannus	D. megagracilis	Montana			Remains later referred to Tyrannosaurus rex.
Gorgosaurus	G. lancensis	Montana			Remains later referred to Nanotyrannus lancensis.
?Nanotyrannus^[13]	?N. lancensis^[13]	Montana^[13]		"Nearly complete skull."^[41]	A small tyrannosaur, possibly synonymous with Tyrannosaurus.
Tyrannosaurus^[13]	T. rex^[13]	Montana^[13] North Dakota^[14] South Dakota^[15]			A tyrannosaur, known from several specimens including a juvenile nicknamed "Jane". Also found in the Denver, Frenchman, Hill Creek South, Javelina, Kirtland, Lance, McRae, North Horn, Scollard, and Willow Creek Formations.

Turtles

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative data are in small text; ~~crossed out~~ data are discredited.

Turtles reported from the Hell Creek Formation
Genus	Species	State	Stratigraphic position	Material	Notes
Adocus^[42]	Indeterminate^[42]	Montana^[43]
Compsemys^[42]	C. victa^[42]	Montana^[43]
Eubaena^[42]	E. cephalica^[42]	Montana^[43]
Gamerabaena	G. sonsalla	North Dakota
Trionyx^[42]	Indeterminate^[42]	Montana^[43]

Footnotes

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Longrich, N.R., Tokaryk, T. and Field, D.J. (2011). "Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary." Proceedings of the National Academy of Sciences, 108(37): 15253-15257. doi:10.1073/pnas.1110395108
^ Listed as "cf. Barbourula sp." in "Class Amphibia," Estes and Berberian, (1970). Page 4.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p "Class Amphibia," in Estes and Berberian, (1970). Page 4.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ "Class Amphibia," in Estes and Berberian, (1970). Page 4. All taxa listed occur in Montana, see page 1.
^ Listed as "Eopelobates? sp." in "Class Amphibia," Estes and Berberian, (1970). Page 4.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p "Class Osteichthyes," in Estes and Berberian, (1970). Page 3.
^ ^a ^b ^c ^d ^e ^f ^g ^h "Class Osteichthyes," in Estes and Berberian, (1970). Page 3. All taxa listed occur in Montana, see page 1.
^ ^a ^b ^c ^d "Class Osteichthyes," in Estes and Berberian, (1970). Page 4.
^ ^a ^b ^c "Class Osteichthyes," in Estes and Berberian, (1970). Page 4. All taxa listed occur in Montana, see page 1.
^ ^a ^b Listed as "cf. Paralbula casei" in "Class Osteichthyes," Estes and Berberian, (1970). Page 4.
^ ^a ^b ^c ^d ^e ^f "Class Chondrichthyes," in Estes and Berberian, (1970). Page 3.
^ ^a ^b ^c "Class Chondrichthyes," in Estes and Berberian, (1970). Page 3. All taxa listed occur in Montana, see page 1.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^aa ^ab ^ac ^ad ^ae ^af ^ag ^ah ^ai ^aj ^ak ^al ^am ^an ^ao ^ap ^aq ^ar ^as ^at ^au ^av ^aw ^ax ^ay ^az ^ba ^bb ^bc ^bd ^be ^bf ^bg ^bh ^bi ^bj ^bk ^bl ^bm ^bn ^bo ^bp ^bq ^br ^bs ^bt ^bu ^bv ^bw ^bx ^by ^bz ^ca ^cb "Dinosaur distribution (Late Cretaceous; North America; Montana)." Weishampel, et al. (2004). Page 584.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Dinosaur distribution (Late Cretaceous; North America; North Dakota)." Weishampel, et al. (2004). Page 585.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z "Dinosaur distribution (Late Cretaceous; North America; South Dakota)." Weishampel, et al. (2004). Page 586.
^ Listed as "Leptoceratops c.f. gracilis" in "Dinosaur distribution (Late Cretaceous; North America; Montana)." Weishampel, et al. (2004). Page 584.
^ Nicholas R. Longrich (2011). "Titanoceratops ouranous, a giant horned dinosaur from the Late Campanian of New Mexico". Cretaceous Research 32. doi:10.1016/j.cretres.2010.12.007. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WD3-51TPVM1-1&_user=10&_coverDate=12%2F29%2F2010&_rdoc=1&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%236755%239999%23999999999%2399999%23FLA%23display%23Articles)&_cdi=6755&_sort=d&_docanchor=&_ct=21&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8f5e3845b1c44a1dc08c04b09952a44a&searchtype=a.
^ Scannella, J. and Horner, J.R. (2010). "Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae: Chasmosaurinae): synonymy through ontogeny." Journal of Vertebrate Paleontology, 30(4): 1157 - 1168. doi:10.1080/02724634.2010.483632
^ "Table 23.1," in Weishampel, et al. (2004). Page 496.
^ ^a ^b ^c Campione, N.E. and Evans, D.C. (2011). "Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America." PLoS ONE, 6(9): e25186. doi:10.1371/journal.pone.0025186
^ Holtz, Thomas R. Jr. (2011) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.
^ ^a ^b Listed as "?Parasaurolophus walkeri" in "Dinosaur distribution (Late Cretaceous; North America; Montana)." Weishampel, et al. (2004). Page 584.
^ ^a ^b ^c Listed as "?Thescelosaurus garbanii" in "Dinosaur distribution (Late Cretaceous; North America; Montana)." Weishampel, et al. (2004). Page 584.
^ Noted as being present, although misspelled as "Thescelosaurus garbani, in " "Dinosaur distribution (Late Cretaceous; North America; South Dakota)." Weishampel, et al. (2004). Page 586.
^ Boyd, Brown, et al. (2009)
^ Listed as "c.f. Thescelosaurus sp." in "Dinosaur distribution (Late Cretaceous; North America; North Dakota)." Weishampel, et al. (2004). Page 585.
^ ^a ^b ^c ^d Bakker et al. (2006)
^ ^a ^b "Table 21.1," in Weishampel, et al. (2004). Page 465.
^ Listed as "cf. Quetzalcoatlus sp." in Henderson and Peterson (2006) 192–195.
^ ^a ^b ^c Henderson and Peterson (2006) 192–195.
^ Hutchinson and Chiappe, 1998. The first known alvarezsaurid (Theropoda: Aves) from North America. Journal of Vertebrate Paleontology. 18(3), 447-450.
^ Triebold, 1997. The Sandy Site: Small Dinosaurs from the Hell Creek Formation of South Dakota. in Wolberg, Stump and Rosenberg (eds). Dinofest International: Proceedings of a Symposium sponsored by Arizona
^ Listed as "?Ornithomimus sp." in "Dinosaur distribution (Late Cretaceous; North America; North Dakota)." Weishampel, et al. (2004). Page 585.
^ ^a ^b Longrich (2008), pages 983-996.
^ Listed as "c.f. Struthiomimus sp." in "Dinosaur distribution (Late Cretaceous; North America; North Dakota)." Weishampel, et al. (2004). Page 585.
^ ^a ^b "Table 5.1," in Varricchio (2001). Page 44.
^ Referenced by the original, obsolete spelling "Ricardoestesia" in "Dinosaur distribution (Late Cretaceous; North America; North Dakota)." Weishampel, et al. (2004). Page 585.
^ Listed as "?Saurornithoides sp." "Dinosaur distribution (Late Cretaceous; North America; Montana)." Weishampel, et al. (2004). Page 584.
^ ^a ^b "Class Aves," in Estes and Berberian, (1970). Page 7.
^ "Class Aves," in Estes and Berberian, (1970). Page 7. All taxa listed occur in Montana, see page 1.
^ "Table 5.1," in Weishampel, et al. (2004). Page 113.
^ ^a ^b ^c ^d ^e ^f ^g ^h "Order Testudinata," in Estes and Berberian, (1970). Page 5.
^ ^a ^b ^c ^d "Order Testudinata," in Estes and Berberian, (1970). Page 5. All taxa listed occur in Montana, see page 1.

References

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Bakker, R. T., Sullivan, R. M., Porter, V., Larson, P. and Saulsbury, S.J. (2006). "Dracorex hogwartsia, n. gen., n. sp., a spiked, flat-headed pachycephalosaurid dinosaur from the Upper Cretaceous Hell Creek Formation of South Dakota." in Lucas, S. G. and Sullivan, R. M., eds., Late Cretaceous vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 35, pp. 331–345. [1]
Boyd, Clint A.; Brown, Caleb M.; Scheetz, Rodney D.; and Clarke, Julia A. (2009). "Taxonomic revision of the basal neornithischian taxa Thescelosaurus and Bugenasaura". Journal of Vertebrate Paleontology 29 (3): 758–770. doi:10.1671/039.029.0328.
Estes, R., and P. Berberian. 1970. Paleoecology of a late Cretaceous vertebrate community from Montana. Breviora volume 343, 35 pages.
Henderson, M.D. and Peterson, J.E. "An azhdarchid pterosaur cervical vertebra from the Hell Creek Formation (Maastrichtian) of southeastern Montana." Journal of Vertebrate Paleontology, 26(1): 192–195.
Longrich, N. (2008). "A new, large ornithomimid from the Cretaceous Dinosaur Park Formation of Alberta, Canada: Implications for the study of dissociated dinosaur remains." Palaeontology, 54(1): 983-996.
Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana.
Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.

Hell Creek Formation

Contents

Paleobiota

Amphibians

Bony fishes

Cartilaginous fishes

Ornithischians

Ankylosaurs

Ceratopsians

Ornithopods

Pachycephalosaurs

Plants

Pterosaurs

Theropods

Ornithomimosaurs

Oviraptorosaurs

Eumaniraptorans

Tyrannosaurids

Turtles

Footnotes

References

See also

External links