Lance Formation Explained

Lance Formation
Type:	Sedimentary
Age:	Maastrichtian ~
Period:	Maastrichtian
Prilithology:	Sandstone, siltstone, shale
Namedfor:	Lance Creek, Wyoming
Region:	Wyoming
Country:	United States
Underlies:	Fort Union Formation
Overlies:	Meeteetse Formation
Thickness:	up to 600m (2,000feet)

The Lance (Creek) Formation is a division of Late Cretaceous (dating to about 69–66 Ma) rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas. The Lance Formation is Late Maastrichtian in age (Lancian land mammal age), and shares much fauna with the Hell Creek Formation of Montana and North Dakota, the Frenchman Formation of southwest Saskatchewan, and the lower part of the Scollard Formation of Alberta.

The Lance Formation occurs above the Baculites clinolobatus ammonite marine zone in Wyoming, the top of which has been dated to about 69 million years ago, and extends to the K-Pg boundary, 66 million years ago. However, the characteristic land vertebrate fauna of the Lancian age (which take its name from this formation) is only found in the upper strata of the Lance, roughly corresponding to the thinner equivalent formations such as the Hell Creek Formation, the base of which has been estimated at 66.8 million years old.^[1]

Description

The formation is described by W.G. Pierce as thick-bedded, buff-colored sandstone, and drab to green shale. It is Upper Cretaceous in age.^[2]

The formation varies in thickness from about 90 m (300 ft.) in North Dakota, to almost 600 m (2,000 ft.) in parts of Wyoming.

Depositional environment

The Lance Formation was laid down by streams, on a coastal plain along the edge of the Western Interior Seaway. The climate was subtropical; there was no cold season and probably ample precipitation.

Paleontology

At least tens of thousands of Late Cretaceous vertebrate remains have been recovered from the Lance Formation. Fossils ranging from microscopic elements to extensive bonebeds, with nearly complete, sometimes articulated dinosaur skeletons, have been found.^[3] Most other animals known from the formation are freshwater animals, and some are exclusively freshwater forms (for instance, frogs and salamanders). However, marine fossils are also found in the formation, suggesting that the sea was nearby. The bird fauna is mainly composed of orders still existing today.

Coelurosaurs

Birds

Birds reported from the Lance Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Apatornis	A. retusus				Reclassified as Palintropus retusus
Ceramornis	C. major			UCMP 53959 (holotype), a partial coracoid	A possible charadriiform bird
Cimolopteryx	C. petra				Reclassified as Lamarqueavis minima
	C. rara			YPM 1805 (holotype), a partial coracoid	A charadriiform
	C. retusa				Reclassified as Palintropus retusus
	C. minima				Reclassified as Lamarqueavis minima^[4]
"Cimolopteryx"	"C." maxima			UCMP 53973 (holotype), a partial coracoid	A charadriiform bird, not necessarily closely related to Cimolopteryx.^[5]
Graculavus	G. augustus			AMNH 25223, a partial humerus	A possible charadriiform
Lamarqueavis	L. minima			UCMP 53976 (holotype), a partial coracoid	A charadriiform
	L. petra			AMNH 21911 (holotype), a partial coracoid	A charadriiform
Lonchodytes	L. estesi			UCMP 53954 (holotype), a partial tarsometatarsus	A possible procellariiform
"Lonchodytes"	"L." pterygius			UCMP 53961 (holotype), a partial carpometacarpus	A possible charadriiform
"Palaeotringa"	"P." vetus			ANSP 13361 (holotype), a partial tibiotarsus AMNH 25221, a partial tibiotarsus	A bird similar to gruids, idiornithids and presbyornithids.
Palintropus	P. retusus			YPM 513 (holotype), a partial coracoid^[6]	A basal ornithuromorph belonging to Ambiortiformes.
Potamornis	P. skutchi			UCMP 73103 (holotype), a quadrate^[7] tarsometatarsus?^[8]	A hesperornithiform possibly also present in the Hell Creek Formation.
Torotix	T. clemensi			UCMP 53958, a partial humerus^[9]	A possible pelecaniform
Unnamed presbyornithid	Indeterminate			AMNH 21929, a partial scapula AMNH 22603, a partial scapula YPM 868, a partial scapula AMNH 22602, a partial sternum	A presbyornithid^[10]
Unnamed enantiornithean	Unnamed			USNM 2909, a partial metatarsal and pedal phalanges	An enantiornithean, previously referred to "Ornithomimus" minutus^[11]
Unnamed avian	Indeterminate			UCMP 53960, two partial neck vertebrae	An indeterminate avian
Unnamed phalacrocoracid	Indeterminate			AMNH 25272, a femur	A possible phalacrocoracid
Unnamed galloanserine	Indeterminate			UCMP 53969, a quadrate^[12] YPM VP 59473, a partial skeleton consisting of skull, vertebrae and limb material^[13]	A possible galloanserine
"Unnamed ornithurine A"	Indeterminate			UCMP 53962, a partial coracoid UCMP 53963, a partial coracoid AMNH uncatalogued, a partial coracoid	Originally thought to belong to Cimolopteryx rara, but probably a new species. Also present in the Frenchman Formation.
"Unnamed ornithurine C"	Indeterminate			YPM PU 17020, a partial coracoid	Also present in the Hell Creek Formation.
"Unnamed ornithurine E"	Indeterminate			USNM 181923, a partial coracoid USNM 13011, a partial coracoid	Also present in the Hell Creek Formation.
"Unnamed ornithurine F"	Indeterminate			UCMP 53957, a partial coracoid ACM 12359, a partial coracoid	Originally thought to belong to "Cimolopteryx" maxima, but probably a new species.

Other coelurosaurs

Miscellaneous coelurosaurs of the Lance Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Aublysodon	A. amplus			Teeth, type specimen	Dubious tyrannosaurids probably synonymous with Tyrannosaurus rex
A. cristatus			Teeth, type specimen
"Ornithomimus"	"O." sedens			"Sacrum and fragmentary illium"^[14] type specimen	An ornithomimid.
Paronychodon	P. caperatus			Teeth, type specimen	A troodontid
Pectinodon	P. bakkeri			Teeth, type specimen	A troodontid
Tyrannosaurus	T. rex			Several partial specimens and teeth	A tyrannosaurid originally identified from the Hell Creek Formation. Also found in the Denver, Ferris, Frenchman, Javelina, Livingston, McRae, North Horn, Scollard, and Willow Creek Formations. Synonyms with type specimens from this formation include Dynamosaurus imperiosus and Manospondylus gigas.^[15]
Nanotyrannus	N. lancensis				Synonym of Tyrannosaurus.
Unnamed Caenagnathidae^[16] ^[17]	Indeterminate			UCMP 143274	Previously identified as a parrot^[18]

Ornithischia

Ankylosaurs

Ankylosaurs of the Lance Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Ankylosaurus	A. magniventris ^[19]	Wyoming		More than 70 osteoderms and a tooth	An ankylosaurid, originally identified from the Hell Creek Formation.
Denversaurus	D. schlessmani^[20]	South Dakota		A nearly complete skull, several teeth and osteoderms.	A nodosaurid
Edmontonia	E. sp.^[21]	Wyoming		Teeth	A nodosaurid. Fossils have been unearthed in the Hell Creek Formation, the Ferris Formation, the Dinosaur Park Formation, the Horseshoe Canyon Formation, and the Denver Formation.^[22] ^[23] ^[24] ^[25] ^[26]
"Palaeoscincus"	"P. latus"	Wyoming		Teeth	Probably a nodosaurid, but the teeth could also belong to the Pachycephalosauridae.

Marginocephalians

Marginocephalians reported from the Lance Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Agathaumas	A. sylvestris			"Partial sacrum and pelvis,"^[27] type specimen.	A dubious ceratopsid probably synonymous with Triceratops horridus
Leptoceratops	L. gracilis				A ceratopsian
Nedoceratops	N. hatcheri			"[One] skull," type specimen.	A ceratopsid possibly synonymous with Triceratops horridus. Synonyms include Diceratops hatcheri and Diceratus hatcheri.
Pachycephalosaurus	P. wyomingensis			Fragmentary specimens including the type specimen.	A pachycephalosaur. Synonyms with type specimens from this formation include Troodon wyomingensis.
"Palaeoscincus"	"P." latus			"Tooth."^[28]	A dubious pachycephalosaur, previously classified as the ankylosaur Palaeoscincus
Stygimoloch	S. spinifer				A pachycephalosaur possibly synonymous with Pachycephalosaurus wyomingensis^[29]
Torosaurus	T. latus			Several specimens including the type specimen.	A ceratopsid possibly synonymous with Triceratops horridus.^[30] Torosaurus gladius, with type specimen from this formation, is a synonym. Also present in the Frenchman and Hell Creek Formations.
Triceratops	T. horridus T. sp.			"Partial skull and skeleton," type specimen	A ceratopsid, also found in the Evanston, Frenchman, Hell Creek, Laramie, and Scollard Formations. Synonyms with type specimens from this formation include T. ingens and T. sulcatus.

Ornithopods

Indeterminate lambeosaurinae fossils have been found in the Lance Formation.^[31]

Ornithopods of the Lance Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Edmontosaurus	E. annectens			Skull, skeletons, including the type specimen, "mummy", and a bone bed.^[32]	A hadrosaurid. Synonyms from this formation include Anatosaurus annectens and Claosaurus annectens. Also found in the Frenchman, Hell Creek, Laramie and Scollard Formations.
Thescelosaurus	T. neglectus			Well-preserved skeleton, type specimen	A thescelosaurid.^[33] Also found in the Frenchman, Hell Creek, Laramie and Scollard Formations.
Thespesius	T. occidentalis			Teeth, vertebrae, toe bone (including type specimen)	A dubious hadrosaurid possibly synonymous with E. annectens
"Trachodon"	"T." longiceps			One partial jaw (YPM 616), type specimen	A dubious hadrosaurid possibly synonymous with E. annectens

Other vertebrates

Other land vertebrates include pterosaurs (e.g. cf. Azhdarcho), crocodiles, champsosaurs, lizards, snakes, turtles, frogs and salamanders.

Remains of fishes and mammals (i.e. Nanocuris) have also been found in the Lance Formation.

See also

• List of fossil sites (with link directory)
• List of dinosaur-bearing rock formations

External links

• Passport-In-Time Microvertebrate Fossil Project

Notes and References

1. Lehman, T. M., Mcdowell, F. W., & Connelly, J. N. (2006). First isotopic (U-Pb) age for the Late Cretaceous Alamosaurus vertebrate fauna of West Texas, and its significance as a link between two faunal provinces. Journal of Vertebrate Paleontology, 26(4), 922–928.
2. Pierce, W.G., 1997, Geologic map of the Cody 1 degree x 2 degrees quadrangle, northwestern Wyoming: U.S. Geological Survey, Miscellaneous Geologic Investigations Map I-2500, scale 1:250000.
3. Silver, Mark (August 2, 2014) "The Dinosaur Surveyors" The American Surveyor Frederick Maryland
4. Federico L. Agnolin . 2010 . An avian coracoid from the Upper Cretaceous of Patagonia, Argentina . Stvdia Geologica Salmanticensia . 46 . 2 . 99–119 . 0211-8327. 54675909.
5. Nicholas R. Longrich . 2011 . Titanoceratops ouranous, a giant horned dinosaur from the Late Campanian of New Mexico . Cretaceous Research . 32 . 3. 264–276. 10.1016/j.cretres.2010.12.007.
6. Longrich, N. 2009. An ornithurine-dominated avifauna from the Belly River Group (Campanian, Upper Cretaceous) of Alberta, Canada. Cretaceous Research, 30(1): 161–177.
7. Elzanowski, Paul and Stidham, 2001. An avian quadrate from the Late Cretaceous Lance Formation of Wyoming. Journal of Vertebrate Paleontology, 20(4): 712–719.
8. "Table 11.1," in Weishampel, et al. (2004). Page 215.
9. Olson, S.L. and Feduccia, A. 1980. Presbyornis and the origin of the Anseriformes (Aves: Charadriomorphae). Smithsonian Contributions to Paleobiology no. 323.
10. Book: Hope, S.. Chiappe, L.M.. Witmer, L.W.. 2002. The Mesozoic radiation of Neornithes. Mesozoic Birds: Above the Heads of Dinosaurs. 339–388. University of California Press. Berkeley. 978-0520200944.
11. Book: Chiappe, L.M.. Walker, C.A.. 2002. Skeletal morphology and systematics of the Cretaceous Euenantiornithes (Ornithothoraces: Enantiornithes). Mesozoic Birds, above the heads of Dinosaurs. 240–267. University of California Press. Berkeley. 978-0520200944.
12. A.. Elzanowski. T.A.. Stidham. 2011. A Galloanserine Quadrate from the Late Cretaceous Lance Formation of Wyoming. The Auk. 128. 1. 138–145. 10.1525/auk.2011.10113.
13. Brownstein . C. D. . 2024 . A juvenile bird with possible crown-group affinities from a dinosaur-rich Cretaceous ecosystem in North America . BMC Ecology and Evolution . 24 . 1 . 20 . 10.1186/s12862-024-02210-9 . 38336630 . 10858573 . free . 2024BMCEE..24...20B .
14. "Table 6.1," in Weishampel, et al. (2004). Page 139.
15. Dalman . Sebastian . New Examples of Tyrannosaurus rex from the Lance Formation of Wyoming, United States . Bulletin of the Peabody Museum of Natural History . October 2013 . 54 . 2 . 241–254 . 10.3374/014.054.0202 . 128608668 . 16 November 2020.
16. 10.1038/20583 . Dyke . G. J. . Mayr . G. . 1999 . Did parrots exist in the Cretaceous period? . Nature . 399 . 6734. 317–318 . 1999Natur.399..317D . 204993284 .
17. Waterhouse. D. M.. Parrots in a nutshell: The fossil record of Psittaciformes (Aves). 10.1080/08912960600641224. 2006. Historical Biology. 18. 2. 227–238. 2006HBio...18..227W . 83664072.
18. 10.1038/23841 . Stidham . T. . 1998 . A lower jaw from a Cretaceous parrot . Nature . 396 . 6706. 29–30 . 1998Natur.396...29S . 204995638 .
19. The Dinosauria 2nd Edition (David B. Weishampel, Halszka Osmólska and Peter Dodson), p. 584, Dinosaur Distribution (DAVID B. WEISHAMPEL, PAUL M. BARRETT, RODOLFO A. CORIA, JEAN LE LOEUFF, XU XING, ZHAO XIJIN, ASHOK SAHNI, ELIZABETH M. P. GOMANI, CHRISTOPHER R. NOTO)
20. Bakker, R.T. (1988). Review of the Late Cretaceous nodosauroid Dinosauria: Denversaurus schlessmani, a new armor-plated dinosaur from the Latest Cretaceous of South Dakota, the last survivor of the nodosaurians, with comments on Stegosaur-Nodosaur relationships. Hunteria 1(3):1–23.(1988).
21. The Dinosauria 2nd Edition (David B. Weishampel, Halszka Osmólska and Peter Dodson), p. 585, Dinosaur Distribution (DAVID B. WEISHAMPEL, PAUL M. BARRETT, RODOLFO A. CORIA, JEAN LE LOEUFF, XU XING, ZHAO XIJIN, ASHOK SAHNI, ELIZABETH M. P. GOMANI, CHRISTOPHER R. NOTO)
22. Lyson . Tyler R. . Longrich . Nicholas R. . Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America . Proceedings of the Royal Society B: Biological Sciences . 22 April 2011 . 278 . 1709 . 1158–1164 . 10.1098/rspb.2010.1444 . 20943689 . 3049066 .
23. Carpenter . Kenneth . Young . D. Bruce . Late Cretaceous dinosaurs from the Denver Basin, Colorado . Rocky Mountain Geology . 1 January 2002 . 37 . 2 . 237–254 . 10.2113/11 . 19 November 2020.
24. Lillegraven . Jason A. . Eberle . Jaelyn J. . Vertebrate faunal changes through Lancian and Puercan time in southern Wyoming . Journal of Paleontology . July 1999 . 73 . 4 . 691–710 . 10.1017/S0022336000032510 . Cambridge University Press. 133072078 .
25. Book: Dale A. Russel . Makoto Manabe . Synopsis of the Hell Creek (uppermost Cretaceous) dinosaur assemblage . Nichols . Douglas J. . Hartman . Joseph Herbert . Johnson . Kirk R. . The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains: An Integrated Continental Record of the End of the Cretaceous · Issue 361 . 2002 . Geological Society of America . 170 . 9780813723617 . 19 November 2020.
26. Carpenter . Kenneth . Breithaupt . Brent . Latest Cretaceous Occurrence of Nodosaurid Ankylosaurs (Dinosauria, Ornithischia) in Western North America and the Gradual Extinction of the Dinosaurs . Journal of Vertebrate Paleontology . September 2, 1986 . 6 . 3 . 251–257 . 24 April 2021 . Taylor & Francis, Ltd.. 10.1080/02724634.1986.10011619 . 4523098 .
27. "Table 23.1," in Weishampel, et al. (2004). Page 496.
28. "Table 17.1," in Weishampel, et al. (2004). Page 368.
29. Horner J.R. and Goodwin, M.B. (2009). "Extreme cranial ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus." PLoS ONE, 4(10): e7626. Online full text
30. 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.
31. Wegweiser . M. . Breithaupt . B. . Badcock . L. E. . Skinner . E. . Scheffield . J. . DINOSAUR SKIN FOSSILS FROM THIS SIDE OF HELL, WYOMING: PALEOENVIRONMENTAL IMPLICATIONS OF AN UPPER CRETACEOUS KONSERVAT-LAGERSTATTE IN THE LANCE FORMATION . Journal of Vertebrate Paleontology . January 2003 . 23 . 108A .
32. Snyder. Keith. McLain. Matthew. Wood. Jared. Chadwick. Arthur. 2020-05-21. Over 13,000 elements from a single bonebed help elucidate disarticulation and transport of an Edmontosaurusthanatocoenosis. PLOS ONE. 15. 5. e0233182. 10.1371/journal.pone.0233182. 32437394 . 7241792 . 2020PLoSO..1533182S . 1932-6203. free .
33. 10.1671/039.029.0328. Boyd. Clint A.. Brown, Caleb M. . Scheetz, Rodney D. . Clarke, Julia A. . 2009. Taxonomic revision of the basal neornithischian taxa Thescelosaurus and Bugenasaura. Journal of Vertebrate Paleontology. 29. 3. 758–770. 84273584.