Cloverly Formation

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Cloverly Formation
Stratigraphic range: Valanginian-Cenomanian
Cloverly Fm.jpg
Brightly colored strata of the Himes Member of the Cloverly Formation near Shell, Wyoming
Type Geological formation
Sub-unitsPryor Conglomerate, Little Sheep Member, Himes Member
Underlies Thermopolis Shale
Overlies Morrison Formation
Thickness150–400 ft (46–122 m)
Lithology
Primary Mudstone
Other Conglomerate, sandstone
Location
RegionFlag of Wyoming.svg  Wyoming, Flag of Montana.svg  Montana,

Flag of Colorado.svg  Colorado,

Flag of Utah.svg  Utah
CountryFlag of the United States.svg  USA
Type section
Named forCloverly post office, Wyoming
Named byNelson Horatio Darton, 1904 [1]

The Cloverly Formation is a geological formation of Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904. [1] [2] The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service. [3]

Contents

Stratigraphy

The Cloverly Formation rests disconformably on the Morrison Formation and is conformably overlain by the Thermopolis Shale. It is subdivided into a variety of members, depending on the location. [2] [4] In the Bighorn Basin along the Montana-Wyoming border, Moberly (1960) divided the Cloverly into the following three members:

In contrast, Ostrom (1970) divided the formation into four units, which he named Units IV-VII:

Age

A stratigraphic revision of the Cloverly Formation using new uranium lead dates reinterpret the formation as spanning the Valanginian-Cenomanian stages of the Cretaceous period. The individual ages of the members are listed below: [6]

Depositional environment

The sediments of the Cloverly Formation were deposited in alluvial and floodplain environments. The basal conglomerates probably represent braided river deposits, while the sandstones were deposited in fluvial channels. The mudstones that contain most of the fossils represent overbank, lacustrine, and pedogenic deposits. [2] [4] [7]

Vertebrate fauna

Animals recovered include the dinosaurs Deinonychus , Microvenator , Tenontosaurus , Zephyrosaurus and Sauropelta as well as fragmentary remains of Titanosaurs, Ankylosaurs and Ornithomimids. As well, two genera of turtle Naomichelys and Glyptops and the lungfish Ceratodus . [8] Dinosaur eggs have been found in Montana. [9]

References for data: Ostrom 1970; Cifelli et al. 1998; Cifelli 1999; Nydam and Cifelli 2002. Possible goniopholidid remains are known from the formation.

Ornithischians

Ankylosaurs

Ankylosaurs reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Sauropelta [10]

S. edwardsorum [10]

Known from "several articulated skeletons" and common armor plates. [10] Only one partial skull is known. [11]

Articulated skeletons are often encased in carbonate caliche deposits that require acid to be removed safely. [10]

Sauropelta Sauropelta jconway.png
Sauropelta
Tatankacephalus [12] T. cooneyorum [12] Cloverly VII [12] Partial cranium, rib fragments, and osteoderms. [12] Originally described as an ankylosaurid but has since been reclassified as a nodosaurid. [13]

Ceratopsians

Ceratopsians reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Aquilops [14]

A. americanus

  • Montana
Cloverly VII; Himes Member [14]

A basal neoceratopsian.

Aquilops Aquilops NT small.jpg
Aquilops

Ornithopods

Ornithopods reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Tenontosaurus [10]

T. tilleti [10]

Its remains are the most common of any dinosaur of the formation. [10]

Juvenile remains are sometimes found together, suggesting that young Tenontosaurus lived in sibling groups. Deinonychus teeth are sometimes associated with Tenontosaurus, suggesting a predator-prey relationship between the two. [10]

Tenontosaurus Tenontosaurus BW.jpg
Tenontosaurus
Zephyrosaurus Zephyrosaurus in Copenhagen.jpg
Zephyrosaurus

Zephyrosaurus [10]

Z. schaffi [10]

Himes Member

Its remains are "very rare." [10]

An orodromine ornithopod.

Saurischians

Theropod eggshell fragments are known from the formation. Unidentifiable ornithomimid remains are present and most commonly represented by toe bones. [10] Indeterminate allosauroid remains are known from the formation. Remains identified by John Ostrom as Ornithomimus are suspected by Jack Horner to be of a new ornithomimid genus. [10] Possible remains of a microraptorian, a troodontid, and a basal tyrannosauroid similar to Moros have also been found here as well.

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Sauropods

Sauropods reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Rugocaudia [16]

R. cooneyi [16]

Cloverly VII; Himes Member [16]
Sauroposeidon Sauroposeidon proteles.jpg
Sauroposeidon
Sauroposeidon [17] S. protelesCloverly VII; Himes Member [18]

Theropods

Theropods reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages
Acrocanthosaurus [18] A. atokensis [18] Cloverly VII; Himes Member [18]
Acrocanthosaurus Acrocantosaurus4.jpg
Acrocanthosaurus
Deinonychus Deinonychus ewilloughby.png
Deinonychus
Microvenator Microvenator.jpg
Microvenator

Deinonychus [10]

D. antirrhopus [10]

Its remains are "very rare." [10]

Tenontosaurus remains have been recovered in association with Deinonychus teeth, suggesting a predator-prey relationship between the two. [10]

Microvenator [10]

M. celer [10]

Himes Member

Its remains are "extremely rare." [10] Known only from a "[p]artial skeleton with partial skull." [19] The specimen lacks feet and is catalogued as AMNH 3041. [20]

The type specimen AMNH 3041 [10] was recovered by Barnum Brown from Cloverly strata in Montana in 1933.

Ornithomimus [21]

O. velox [21]

Later found to be indeterminate ornithomimid remains. [21]

Mammals

Mammals reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Astroconodon

A. sp. [22]

Previously referred as "Cloverly triconodont"
Gobiconodon GobiconodonDB15.jpg
Gobiconodon

cf. Atokatheridium

Indeterminate

Bryceomys

B. sp.

Corviconodon

C. montanensis

Gobiconodon

G. ostromi

Janumys

J. sp.

Montanalestes

M. keeblerorum

cf. Oklatheridium

Indeterminate

cf. Paracimexomys

Indeterminate

Spalacotheriidae Indeterminate

Crocodyliforms

Crocodyliforms reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotes

cf. Atoposauridae

Indeterminate

cf. Bernissartidae

Indeterminate

cf. Goniopholididae

Indeterminate|

cf. Pholidosauridae

Indeterminate

Turtles

Turtles reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotes

Cryptodira

Indeterminate

" Glyptops " [10]

"G". pervicax [10]

Naomichelys [10]

N. speciosa [10]

Testudinata

Indeterminate

Lepidosaurs

Lepidosaurs reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotes

Paramacellodus

P. keebleri

Paramacellodidae?

Indeterminate

Ptilotodon

P. wilsoni

Also known from the Antlers Formation

Teiidae

Indeterminate

Amphibians

Amphibians reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Albanerpeton

A. ektopistikon [23]

Albanerpeton Albanerpeton inexpectatum.jpg
Albanerpeton
Anura

Indeterminate

Batrachosauroididae

Indeterminate

cf. Scapherpetontidae

Indeterminate

cf. Scotiophryne

Indeterminate

Bony fish

Osteichthyes reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotesImages

Ceratodus [10]

C. frazieri [10]

Ceratodus Ceratodus.jpg
Ceratodus

C. nirumbee [24]

aff. Lepidotes

Indeterminate

aff. Pycnodontidae

Indeterminate

Vidalamiinae

Indeterminate

Cartilaginous fish

Chondrichthyes reported from the Cloverly Formation
GenusSpeciesStateStratigraphic positionMaterialNotes

Egertonodus

E. sp.

Hybodus

H. parvidens

Lonchidion

L. sp.

Parvodus

P. sp.

Pseudohypolophus

P. sp.

See also

Footnotes

  1. 1 2 Darton, N.H. 1904. Comparison of the stratigraphy of the Black Hills, Bighorn Mountains, and Rocky Mountain Front Range. Geological Society of America Bulletin, v. 15, p. 379-448.
  2. 1 2 3 U.S. Geological Survey (1993). "Geologic Unit: Cloverly" . Retrieved 2014-12-23.
  3. "National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)". www.nps.gov. Retrieved 2019-03-22. Year designated: 1973
  4. 1 2 Moberly, R.M., Jr., 1960, Morrison, Cloverly, and Sykes Mountain formations, northern Bighorn basin, Wyoming and Montana: Geological Society of America Bulletin, v. 71, no. 8, p. 1137-1176.
  5. Ostrom, John H. (1970). Stratigraphy and paleontology of the cloverly formation (Lower Cretaceous) of the Bighorn Basin Area, Wyoming and Montana. Peabody Mus. of Nat. History, Univ. OCLC   258060311.
  6. D'Emic, Michael D.; Foreman, Brady Z.; Jud, Nathan A.; Britt, Brooks B.; Schmitz, Mark; Crowley, James L. (2019-04-01). "Chronostratigraphic Revision of the Cloverly Formation (Lower Cretaceous, Western Interior, USA)". Bulletin of the Peabody Museum of Natural History. 60 (1): 3. doi:10.3374/014.060.0101. ISSN   0079-032X. S2CID   132032611.
  7. May, M.T. 1992. Intra- and extrabasinal tectonism, climate and intrinsic threshold cycles as possible controls on Early Cretaceous fluvial architecture, Wind River basin, Wyoming. In: Sundell, K.A., and Anderson, T.C., eds., Rediscover the Rockies: Wyoming Geological Association Field Conference Guidebook, 43rd Annual Field Conference, Casper, WY, September 12–19, 1992, no. 43, p. 61-74.
  8. Oreska, Matthew P. J.; Carrano, Matthew T.; Dzikiewicz, Katherine M. (2013). "Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), I: faunal composition, biogeographic relationships, and sampling". Journal of Vertebrate Paleontology. 33 (2): 264–292. Bibcode:2013JVPal..33..264O. doi:10.1080/02724634.2012.717567. ISSN   0272-4634.
  9. 1 2 "3.11 Montana, United States; 1. Cloverly Formation," in Weishampel, et al. (2004). Page 556.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Horner. Pp. 93-100.
  11. "Table 17.1," in Weishampel, et al. (2004). Page 365.
  12. 1 2 3 4 5 Parsons, William L.; Parsons, Kristen M. (2009). "A new ankylosaur (Dinosauria: Ankylosauria) from the Lower Cretaceous Cloverly Formation of central Montana". Canadian Journal of Earth Sciences. 46 (10): 721–738. Bibcode:2009CaJES..46..721S. doi:10.1139/E09-045.
  13. Richard S. Thompson; Jolyon C. Parish; Susannah C. R. Maidment & Paul M. Barrett (2012). "Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora)". Journal of Systematic Palaeontology. 10 (2): 301–312. Bibcode:2012JSPal..10..301T. doi:10.1080/14772019.2011.569091. S2CID   86002282.
  14. 1 2 Farke, Andrew A.; Maxwell, W. Desmond; Cifelli, Richard L.; Wedel, Mathew J. (2014-12-10). "A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America, and the Biogeography of Neoceratopsia". PLOS ONE. 9 (12): e112055. Bibcode:2014PLoSO...9k2055F. doi: 10.1371/journal.pone.0112055 . ISSN   1932-6203. PMC   4262212 . PMID   25494182.
  15. 1 2 3 4 "3.12 Wyoming, United States; 2. Cloverly Formation," in Weishampel, et al. (2004). Page 556.
  16. 1 2 3 4 D. Cary Woodruff (2012). "A new titanosauriform from the Early Cretaceous Cloverly Formation of Montana". Cretaceous Research. 36: 58–66. Bibcode:2012CrRes..36...58W. doi:10.1016/j.cretres.2012.02.003.
  17. D'Emic, M.D., and B.Z. Foreman. (2012). The beginning of the sauropod dinosaur hiatus in North America: insights from Wyoming's Lower Cretaceous Cloverly Formation. Journal of Vertebrate Paleontology32(4):883–902.
  18. 1 2 3 4 5 6 D'Emic, Michael D.; Melstrom, Keegan M.; Eddy, Drew R. (2012). "Paleobiology and geographic range of the large-bodied Cretaceous theropod dinosaur Acrocanthosaurus atokensis". Palaeogeography, Palaeoclimatology, Palaeoecology. 333–334: 13–23. Bibcode:2012PPP...333...13D. doi:10.1016/j.palaeo.2012.03.003.
  19. "Table 8.1," in Weishampel, et al. (2004). Page 167.
  20. "Table 5.1," in Varricchio (2001). Page 44.
  21. 1 2 3 "3.11 Wyoming, United States; 1. Cloverly Formation" and "3.12 Montana, United States; 2. Cloverly Formation," in Weishampel, et al. (2004). Page 556.
  22. Hoffmann, Simone; Kirk, E. Christopher; Rowe, Timothy B.; Cifelli, Richard L. (2023-08-05). "Petrosal morphology of the Early Cretaceous triconodontid Astroconodon from the Cloverly Formation (Montana, USA)". Journal of Mammalian Evolution. 30 (4): 819–844. doi:10.1007/s10914-023-09673-5. ISSN   1573-7055.
  23. Carrano, Matthew T.; Oreska, Matthew P. J.; Murch, Abree; Trujillo, Kelli C.; Chamberlain, Kevin R. (2021-08-27). "Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), III: a new species of Albanerpeton, with biogeographic and paleoecological implications". Journal of Vertebrate Paleontology. 41 (5). Bibcode:2021JVPal..41E3372C. doi:10.1080/02724634.2021.2003372. ISSN   0272-4634.
  24. Frederickson J.A. and Cifelli R.L. (2016) New Cretaceous lungfishes (Dipnoi, Ceratodontidae) from western North America. Journal of Paleontology.

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References