Cloverly Formation

{{Infobox Rockunit

| name = Cloverly Formation

| image = Cloverly Fm.jpg

| caption = Brightly colored strata of the Himes Member of the Cloverly Formation near Shell, Wyoming

| type = Geological formation

| age = {{Fossil range|Valanginian|Cenomanian|Valanginian-Cenomanian}}

| period = Albian

| prilithology = Mudstone

| otherlithology = Conglomerate, sandstone

| namedfor = Cloverly post office, Wyoming

| namedby = Nelson Horatio Darton, 1904Darton, 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.

| region = Wyoming, Montana, Colorado, Utah

| country = United States

| coordinates =

| unitof =

| subunits = Pryor Conglomerate, Little Sheep Member, Himes Member

| underlies = Thermopolis Shale

| overlies = Morrison Formation

| thickness = {{convert|150|-|400|ft|m|abbr=on}}

| extent =

| area =

| map =

| map_caption =

}}

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.{{Cite web|url=http://ngmdb.usgs.gov/Geolex/UnitRefs/CloverlyRefs_7546.html|title=Geologic Unit: Cloverly|author=U.S. Geological Survey|date=1993|accessdate=2014-12-23}} 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.{{Cite web

|url=https://www.nps.gov/subjects/nnlandmarks/site.htm?Site=CLFO-MT

|title=National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)

|website=www.nps.gov|language=en

|quote=Year designated: 1973

|access-date=2019-03-22}}

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.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. In the Bighorn Basin along the Montana-Wyoming border, Moberly (1960) divided the Cloverly into the following three members:

The Pryor Conglomerate lies at the base and contains abundant black chert. It is named from thick beds exposed on the west side of the Pryor Mountains.
The Little Sheep Member lies in the middle and is composed of pale-purple, gray to almost white, bentonitic mudstone.
The uppermost unit is the Himes Member, which contains some coarse-grained channel sandstone deposits, but consists primarily of brightly multicolored (variegated) mudstones.

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

Unit IV equates to the Pryor Conglomerate of Moberly and consists of a conglomerate or conglomeratic sandstone.
Unit V, overlaying Unit IV, consists of a lower grey-to-purple claystone with abundant fist-sized chalcedony and barite concretions; the unit is highly bentonitic and contains occasional channel sands.
Unit VI is a discontinuous "salt and pepper" cross-stratified channel sandstone with occasional conglomerate, considered by Moberly to be part of the Himes Member.
Unit VII, the uppermost, is a maroon to orange claystone with occasional highly rounded and polished pebbles of silica.{{Cite book|last=Ostrom, John H.|url=http://worldcat.org/oclc/258060311|title=Stratigraphy and paleontology of the cloverly formation (Lower Cretaceous) of the Bighorn Basin Area, Wyoming and Montana|date=1970|publisher=Peabody Mus. of Nat. History, Univ|oclc=258060311}}

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:{{Cite journal |last1=D'Emic |first1=Michael D. |last2=Foreman |first2=Brady Z. |last3=Jud |first3=Nathan A. |last4=Britt |first4=Brooks B. |last5=Schmitz |first5=Mark |last6=Crowley |first6=James L. |date=2019-04-01 |title=Chronostratigraphic Revision of the Cloverly Formation (Lower Cretaceous, Western Interior, USA) |url= |journal=Bulletin of the Peabody Museum of Natural History |volume=60 |issue=1 |pages=3 |doi=10.3374/014.060.0101 |s2cid=132032611 |issn=0079-032X}}

Pryor Conglomerate; 140-130 Ma (Valanginian-Hauterivian)
Little Sheep Member; 130-124 Ma (marine section) (Hauterivian-Barremian) and 124-109 Ma (terrestrial section) (Barremian-Albian)
Himes Member; 109-98 Ma (Albian-Cenomanian)

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.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.

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.{{Cite journal |last1=Oreska |first1=Matthew P. J. |last2=Carrano |first2=Matthew T. |last3=Dzikiewicz |first3=Katherine M. |date=2013 |title=Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), I: faunal composition, biogeographic relationships, and sampling |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2012.717567 |journal=Journal of Vertebrate Paleontology |language=en |volume=33 |issue=2 |pages=264–292 |doi=10.1080/02724634.2012.717567 |bibcode=2013JVPal..33..264O |issn=0272-4634|url-access=subscription }} Dinosaur eggs have been found in Montana.

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

= Dinosaurs =

==Ornithischians==

=== Ankylosaurs ===

colspan="7" align="center" \|Ankylosaurs reported from the Cloverly Formation
class="wikitable" align="center" width="100%"
Genus ! Species ! State ! Stratigraphic position ! width="20%"\| Material ! width="30%"\| Notes ! Images
Sauropelta \| S. edwardsorum \| Montana Wyoming \| \| Known from "several articulated skeletons" and common armor plates. Only one partial skull is known."Table 17.1," in Weishampel, et al. (2004). Page 365. \| Articulated skeletons are often encased in carbonate caliche deposits that require acid to be removed safely. \| rowspan = 2\| Image:Sauropelta jconway.png]]
Tatankacephalus{{cite journal \|last1=Parsons \|first1=William L. \|last2=Parsons \|first2=Kristen M. \|year=2009 \|title=A new ankylosaur (Dinosauria: Ankylosauria) from the Lower Cretaceous Cloverly Formation of central Montana \|journal=Canadian Journal of Earth Sciences \|volume=46 \|issue=10 \|pages=721–738 \|bibcode=2009CaJES..46..721S \|doi=10.1139/E09-045}} \|T. cooneyorum \| Montana \|Cloverly VII \|Partial cranium, rib fragments, and osteoderms. \|Originally described as an ankylosaurid but has since been reclassified as a nodosaurid.{{Cite journal \|author=Richard S. Thompson \|author2=Jolyon C. Parish \|author3=Susannah C. R. Maidment \|author4=Paul M. Barrett \|name-list-style=amp \|year=2012 \|title=Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora) \|journal=Journal of Systematic Palaeontology \|volume=10 \|issue=2 \|pages=301–312 \|doi=10.1080/14772019.2011.569091 \|bibcode=2012JSPal..10..301T \|s2cid=86002282}}

=== Ceratopsians ===

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Ceratopsians reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! width="20%"| Material

! width="30%"| Notes

! Images

Aquilops{{Cite journal |last1=Farke |first1=Andrew A. |last2=Maxwell |first2=W. Desmond |last3=Cifelli |first3=Richard L. |last4=Wedel |first4=Mathew J. |date=2014-12-10 |title=A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America, and the Biogeography of Neoceratopsia |journal=PLOS ONE |language=en |volume=9 |issue=12 |pages=e112055 |doi=10.1371/journal.pone.0112055 |issn=1932-6203 |pmc=4262212 |pmid=25494182|bibcode=2014PLoSO...9k2055F |doi-access=free }}

A. americanus

Montana

|Cloverly VII; Himes Member

A basal neoceratopsian.

Image:Aquilops NT small.jpg]]

=== Ornithopods ===

colspan="7" align="center" \|Ornithopods reported from the Cloverly Formation
class="wikitable" align="center" width="100%"
Genus ! Species ! State ! Stratigraphic position ! width="20%"\| Material ! width="30%"\| Notes ! Images
Tenontosaurus \| T. tilleti \| Montana Wyoming \| \| Its remains are the most common of any dinosaur of the formation. \| 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. \| rowspan="100" \| Image:Tenontosaurus BW.jpg]] File:Zephyrosaurus in Copenhagen.jpg]]
Zephyrosaurus \| Z. schaffi \| Montana \|Himes Member \| Its remains are "very rare." \| An orodromine ornithopod.

==Saurischians==

Theropod eggshell fragments are known from the formation. Unidentifiable ornithomimid remains are present and most commonly represented by toe bones. 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. Possible remains of a microraptorian, a troodontid, and a basal tyrannosauroid similar to Moros have also been found here as well.

=== Sauropods ===

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Sauropods reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! width="20%"| Material

! width="30%"| Notes

! Images

Rugocaudia{{cite journal |author=D. Cary Woodruff |year=2012 |title=A new titanosauriform from the Early Cretaceous Cloverly Formation of Montana |journal=Cretaceous Research |volume=36 |pages= 58–66|doi=10.1016/j.cretres.2012.02.003 |bibcode=2012CrRes..36...58W }}

R. cooneyi

Montana

|Cloverly VII; Himes Member

| rowspan = 2| File:Sauroposeidon proteles.jpg]]

SauroposeidonD'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 Paleontology 32(4):883–902.

|S. proteles

Wyoming

|Cloverly VII; Himes Member

=== Theropods ===

colspan="7" align="center" \|Theropods reported from the Cloverly Formation
class="wikitable" align="center" width="100%"
Genus ! Species ! State ! Stratigraphic position ! width="20%"\| Material ! width="30%"\| Notes ! Images
Acrocanthosaurus{{cite journal \|last=D'Emic \|first=Michael D. \|author2=Melstrom, Keegan M. \|author3= Eddy, Drew R. \|year=2012 \|title=Paleobiology and geographic range of the large-bodied Cretaceous theropod dinosaur Acrocanthosaurus atokensis \|journal=Palaeogeography, Palaeoclimatology, Palaeoecology \|volume=333–334 \|pages=13–23 \|doi=10.1016/j.palaeo.2012.03.003 \|bibcode=2012PPP...333...13D }} \| A. atokensis \| Wyoming \| Cloverly VII; Himes Member \| A partial skeleton consists of a dorsal vertebral centrum, caudal vertebral neural arch, right and left pubes, right femur, proximal right fibula, and several fragments. \| A carcharodontosaurid. \| rowspan="99" \| File:Acrocantosaurus4.jpg]] File:Deinonychus ewilloughby.png]] Image:Microvenator.jpg]]
Deinonychus \| D. antirrhopus \| Montana Wyoming \| \| Its remains are "very rare." \| A dromaeosaur. Tenontosaurus remains have been recovered in association with Deinonychus teeth, suggesting a predator-prey relationship between the two.
Microvenator \| M. celer \| Montana Wyoming \|Himes Member \| Its remains are "extremely rare." Known only from a "[p]artial skeleton with partial skull.""Table 8.1," in Weishampel, et al. (2004). Page 167. The specimen lacks feet and is catalogued as AMNH 3041."Table 5.1," in Varricchio (2001). Page 44. \| The type specimen AMNH 3041 was recovered by Barnum Brown from Cloverly strata in Montana in 1933.
style="background:#f3e9f3;" \| Ornithomimus \|style="background:#f3e9f3;" \| O. velox"3.11 Wyoming, United States; 1. Cloverly Formation" and "3.12 Montana, United States; 2. Cloverly Formation," in Weishampel, et al. (2004). Page 556. \|style="background:#f3e9f3;" \| Montana"3.11 Montana, United States; 1. Cloverly Formation," in Weishampel, et al. (2004). Page 556. Wyoming"3.12 Wyoming, United States; 2. Cloverly Formation," in Weishampel, et al. (2004). Page 556. \|style="background:#f3e9f3;" \| \|style="background:#f3e9f3;" \| \|style="background:#f3e9f3;" \| Later found to be indeterminate ornithomimid remains.

=Mammals=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Mammals reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

! Images

Astroconodon

A. sp.{{Cite journal |last1=Hoffmann |first1=Simone |last2=Kirk |first2=E. Christopher |last3=Rowe |first3=Timothy B. |last4=Cifelli |first4=Richard L. |date=2023-08-05 |title=Petrosal morphology of the Early Cretaceous triconodontid Astroconodon from the Cloverly Formation (Montana, USA) |url=https://doi.org/10.1007/s10914-023-09673-5 |journal=Journal of Mammalian Evolution |volume=30 |issue=4 |pages=819–844 |language=en |doi=10.1007/s10914-023-09673-5 |issn=1573-7055|url-access=subscription }}

|Previously referred as "Cloverly triconodont"

| rowspan="99" |File:GobiconodonDB15.jpg]]

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=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Crocodyliforms reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

cf. Atoposauridae

|Indeterminate

cf. Bernissartidae

|Indeterminate

cf. Goniopholididae

Indeterminate|

cf. Pholidosauridae

|Indeterminate

=Turtles=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Turtles reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

Cryptodira

|Indeterminate

"Glyptops"Horner. Pp. 93-100.

"G". pervicax

Naomichelys

N. speciosa

Testudinata

|Indeterminate

=Lepidosaurs=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Lepidosaurs reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

Paramacellodus

P. keebleri

Paramacellodidae?

|Indeterminate

Ptilotodon

P. wilsoni

|Also known from the Antlers Formation

Teiidae

|Indeterminate

=Amphibians=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Amphibians reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

! Images

Albanerpeton

A. ektopistikon{{Cite journal |last1=Carrano |first1=Matthew T. |last2=Oreska |first2=Matthew P. J. |last3=Murch |first3=Abree |last4=Trujillo |first4=Kelli C. |last5=Chamberlain |first5=Kevin R. |date=2021-08-27 |title=Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), III: a new species of Albanerpeton, with biogeographic and paleoecological implications |url=http://dx.doi.org/10.1080/02724634.2021.2003372 |journal=Journal of Vertebrate Paleontology |volume=41 |issue=5 |doi=10.1080/02724634.2021.2003372 |bibcode=2021JVPal..41E3372C |issn=0272-4634|url-access=subscription }}

| rowspan="99" |

File:Albanerpeton_inexpectatum.jpg]]

Anura

Indeterminate

Batrachosauroididae

Indeterminate

Ostrombatrachos

O. nodos{{Cite journal |last1=Oreska |first1=M. P. J. |last2=DeMar |first2=D. G. |last3=Gardner |first3=J. D. |last4=Carrano |first4=M. T. |year=2024 |title=Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), IV: the oldest edentulous frog (Salientia) from Laurasia |journal=Journal of Vertebrate Paleontology |volume=44 |issue=1 |at=e2399102 |doi=10.1080/02724634.2024.2399102 |bibcode=2024JVPal..44E9102O }}

cf. Scapherpetontidae

Indeterminate

cf. Scotiophryne

Indeterminate

=Bony fish=

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Osteichthyes reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

! Images

rowspan=2|

Ceratodus

C. frazieri

| rowspan="99" |

Image:Ceratodus.jpg]]

C. nirumbeeFrederickson J.A. and Cifelli R.L. (2016) New Cretaceous lungfishes (Dipnoi, Ceratodontidae) from western North America. Journal of Paleontology.

aff. Lepidotes

Indeterminate

aff. Pycnodontidae

Indeterminate

Vidalamiinae

Indeterminate

=Cartilaginous fish =

class="wikitable" align="center" width="100%"

colspan="7" align="center" |Chondrichthyes reported from the Cloverly Formation

Genus

! Species

! State

! Stratigraphic position

! Material

! Notes

Egertonodus

E. sp.

Hybodus

|H. parvidens

Lonchidion

L. sp.

Parvodus

|P. sp.

Pseudohypolophus

|P. sp.

Footnotes

References

Burton, D., Greenhalgh, B.W., Britt, B.B., Kowallis, B.J., Elliott, W.S., and Barrick, R. 2006. New radiometric ages from the Cedar Mountain Formation, Utah and the Cloverly Formation, Wyoming: implications for contained dinosaur faunas. Geological Society of America Abstracts with Programs 38(7): 52.
Chen, Z.-Q. and Lubin, S. 1997. A fission track study of the terrigenous sedimentary sequences of the Morrison and Cloverly Formations in northeastern Bighorn Basin, Wyoming. The Mountain Geologist 34:51-62.
Cifelli, R.L. 1999. Tribosphenic mammal from the North American Early Cretaceous. Nature 401:363-366.
Cifelli, R.L., Wible, J.R., and Jenkins, F.A. 1998. Triconodont mammals from the Cloverly Formation (Lower Cretaceous), Montana and Wyoming. Journal of Vertebrate Paleontology 18: 237-241.
Horner, John R. Dinosaurs Under the Big Sky (Cloverly Formation). Mountain Press Publishing Company. pp. 93–100. {{ISBN|0-87842-445-8}}.
Nydam, R.L., and Cifelli, R.L. 2002. Lizards from the Lower Cretaceous (Aptian-Albian) Antlers and Cloverly Formations. Journal of Vertebrate Paleontology 22: 286-298.
Ostrom, J. H. 1970. Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana. Peabody Museum Bulletin 35:1-234
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}}.