Fort Union Formation
Stratigraphic range: Maastrichtian-Selandian (Lancian-Clarkforkian)
~66–58 Ma
Fossils from the Fort Union Formation
TypeGeological formation
Sub-unitsAtwell Gulch, China Butte, Ekalaka, Lebo, lower Ludlow, Overland, Rock Bench Quarry, Sentinel Butte, Shotgun, Somber beds, Tongue River, Tullock, upper Ludlow, Polecat Bench Formation
UnderliesWasatch Formation
OverliesHell Creek Formation, Lance Formation
Lithology
PrimarySandstone, shale
OtherCoal
Location
RegionMontana, North Dakota
Wyoming, Colorado
Country United States
ExtentPowder River Basin
Fort Union Formation - stratigraphy

The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.[1]

Description

The Fort Union is mostly of Paleocene age and represents a time of extensive swamps as well as fluvial and lacustrine conditions. The rocks are more sandy in southwestern Wyoming and more coal-bearing in northeast Wyoming and southeast Montana, reflecting a general change from rivers and lakes in the west to swamps in the east, but all three environments were present at various times in most locations.[2]

Coal in the Fort Union in the Powder River Basin occurs mainly in the Tongue River Member, where as many as 32 coal seams total more than 300 feet in thickness.[1] One such bed, the Wyodak Coal near Gillette, Wyoming, is as much as 110 feet (34 m) thick. Most of the coals in the Fort Union Formation are ranked subbituminous.[3]

Fossil content

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

Mammals

Cimolestans

Cimolestans reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Crustulus C. fontanus Northeastern Montana.[4] Tullock Member.[4] An isolated upper molar.[4] A pantodont.

Leptictids

Leptictids reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Prodiacodon P. crustulum Garfield & McCone counties, Montana.[5] Tullock Member.[5] Fragmentary dentary & isolated teeth.[5] A leptictid.

Marsupials

Marsupials reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Peradectes P. sp. Swain Quarry, Wyoming.[6] Upper & lower molars.[6] Reassigned to Swaindelphys.
Swaindelphys S. cifellii Swain Quarry, Wyoming.[6] Upper & lower molars.[6] An opossum.

Primatomorphs

Primatomorphs reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Carpodaptes C. sp. Wind River Basin, Wyoming.[7] Shotgun Member.[7] 2 isolated fourth lower premolars.[7] A carpolestid.
Chiromyoides C. caesor Hell's Half Acre (UCM locality 78009), Mesa County, Colorado.[8] A single upper incisor (UCM 53515).[8] A plesiadapid.
C. gigas Piceance Creek Basin, Colorado.[8] Multiple teeth.[8] A plesiadapid.
C. sp. UCM locality 78060, Colorado.[8] A left molar (UCM 41606).[8] A plesiadapid.
Elphidotarsius E. shotgunensis Wind River Basin, Wyoming.[7] Shotgun Member.[7] Right ramus of mandible & isolated teeth.[7] A carpolestid.
Nannodectes N. gazini Fremont County, Colorado.[8] A right maxilla (USGS 16872).[8] A plesiadapid.
Palaechthon P., near P. alticuspis Wind River Basin, Wyoming.[7] Shotgun Member.[7] 3 upper molars & 4 lower molars.[7] A plesiadapiform.
P. woodi Wind River Basin, Wyoming.[7] Shotgun Member.[7] A lower jaw & 13 isolated teeth.[7] A plesiadapiform.
Palenochtha P. cf. minor Wind River Basin, Wyoming.[7] Shotgun Member.[7] 5 lower teeth.[7] A plesiadapiform.
Paromomys P., near P. depressidens Wind River Basin, Wyoming.[7] Shotgun Member.[7] Approximately 12 upper teeth, 8 isolated lower teeth & a jaw fragment.[7] A paromomyid.
Phenacolemur P. fremontensis Wind River Basin, Wyoming.[7] Shotgun Member.[7] A lower jaw & isolated teeth.[7] A paromomyid.
P. cf. frugivorus Wind River Basin, Wyoming.[7] Shotgun Member.[7] 2 upper molars & 8 isolated lower molars.[7] A paromomyid.
Plesiadapis P. dubius Piceance Creek Basin, Colorado.[8] Jaw elements & teeth.[8] A plesiadapid.
P. fodinatus Piceance Creek Basin, Colorado.[8] Jaw elements & teeth.[8] A plesiadapid.
P. sp. Wind River Basin, Wyoming.[7] Shotgun Member.[7] 5 lower molars, 3 anterior upper molars & a premolar.[7] A plesiadapid.
Plesiolestes P. cf. problematicus Wind River Basin, Wyoming.[7] Shotgun Member.[7] Approximately 45 isolated teeth.[7] A plesiadapiform.
Pronothodectes P. intermedius Wind River Basin, Wyoming.[7] Shotgun Member.[7] Jaw elements & teeth.[7] A plesiadapid.
Purgatorius P. janisae 'Harley's Point’ UCMP locality V77087, Garfield County, Montana.[9] Tullock Member.[9] UCMP 150018 (right m1), and UCMP 192398 (left m3).[9] A purgatoriid.
P. mckeeveri Garfield County, Montana.[9] Tullock Member.[9] Dentary remains & teeth.[9] A purgatoriid.
P. cf. P. mckeeveri Harley's Point’ UCMP locality V77087, Garfield County, Montana.[9] Tullock Member.[9] UCMP 150019 (right M2), and UCMP 150020 (right M2).[9] A purgatoriid.
Torrejonia Cf. T. wilsoni Wind River Basin, Wyoming.[7] Shotgun Member.[7] About 14 lower teeth & possibly 3 upper molars.[7] A plesiadapiform.
Zanycteris Z. honeyi UMC locality number 92177, Colorado.[10] Atwell Gulch Member.[10] Right maxilla (UCM 87378).[10] A plesiadapiform.

Ungulates

Ungulates reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Dissacus D. argenteus Princeton Quarry, Park County, Wyoming.[11] Upper part of the formation.[11] Jaw elements & teeth.[11] A mesonychid.
D. cf. navajovius Princeton Quarry, Park County, Wyoming.[11] Upper part of the formation.[11] Jaw elements & teeth.[11] Specimens reassigned to D. argenteus.
D. praenuntius Park County, Wyoming.[11] Upper part of the formation.[11] Mandible (YPM-PU 16159).[11] A mesonychid also known from the Willwood Formation.
Ectocion E. mediotuber Princeton Quarry, Wyoming.[12] Dentary.[12] A phenacodontid.
Periptychus P. carinidens Makoshika State Park, Montana.[13] A periptychid also found in the Nacimiento, North Horn, Black Peaks & Animas formations.
Sigynorum S. magnadivisus Great Divide Basin, southern Wyoming.[14] China Butte Member.[14] An arctocyonid.

Reptiles

Birds

A partial ornithurine coracoid bone found in this formation is identical to others found in the older Hell Creek Formation. At present, this unnamed species is the only known individual bird species that have survived the Cretaceous–Paleogene extinction event.[15]

Birds reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Lithornis L. celetius Bangtail Quarry, Sedan Quadrangle, Park County, Montana.[16] A lithornithid.

Crocodilians

Crocodilians reported from the Fort Union Formation
Genus Species Location Stratigraphic member Material Notes Images
Allognathosuchus A. sp. Princeton Quarry, Park County, Wyoming.[17] Anterior end of left dentary (PU 16988).[17] A crocodilian.

Squamates

Squamates reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Anguidae Genus & species indeterminate Swain Quarry, Carbon County, Wyoming.[18] Fragmentary jaw elements.[18] An anguid lizard.
cf. Anguidae Swain Quarry, Carbon County, Wyoming.[18] 6 partial dentaries.[18] Provisionally referred to anguid lizards based on size & shape.
Contogenys cf. C. sloani Swain Quarry, Carbon County, Wyoming.[18] Posterior part of a right maxilla (AMNH 12069).[18] A skink.
Exostinus E. cf. E. lancensis Swain Quarry, Carbon County, Wyoming.[18] 4 partial dentaries.[18] A xenosaurid lizard.
E. rugosus Princeton & Schaff quarries, Park County, Wyoming.[17] Multiple specimens.[17] A xenosaurid lizard.
Glyptosaurinae Genus & species indeterminate Swain Quarry, Carbon County, Wyoming.[18] Several jaw remains.[18] A glyptosaurine lizard.
Glyptosaurinae or Odaxosaurinae Genus & species indeterminate Swain Quarry, Carbon County, Wyoming.[18] Fragmentary jaw elements & osteoderms.[18] Indeterminate lizard remains.
Machaerosaurus M. torrejonensis Swain Quarry, Carbon County, Wyoming.[18] Numerous jaw elements.[18] An anguid lizard also known from the Nacimiento Formation.
Odaxosaurus O. piger Swain Quarry, Carbon County, Wyoming.[18] Many fragmentary jaw remains.[18] An anguid lizard.
Oligodontosaurus O. wyomingensis Park County, Wyoming.[17] A left mandible (PU 14246).[17] An amphisbaenian.
Palaeosaniwa cf. P. canadensis Swain Quarry, Carbon County, Wyoming.[18] Medial part of left dentary (AMNH 15957).[18] A large anguimorph lizard.
Palaeoxantusia P. fera Swain Quarry, Carbon County, Wyoming.[18] Numerous jaw elements.[18] A night lizard.
Pancelosaurus P. piger Princeton, Fritz & Schaff quarries, Park County, Wyoming.[17] Multiple skull elements.[17] An anguid lizard.
Provaranosaurus P. acutus Princeton Quarry, Park County, Wyoming.[17] PU 14243 (left maxilla), 14561 (anterior portion of left dentary) & 17145 ( fragment of left maxilla).[17] A palaeovaranid lizard.
cf. P. sp. Swain Quarry, Carbon County, Wyoming.[18] 3 partial dentaries (AMNH 14306, 14307 & 14309).[18] A palaeovaranid lizard.
Rhineuridae Unidentified genus & species Fritz Quarry, Park County, Wyoming.[17] An almost complete right dentary & a broken vertebra (PU 18627).[17] An amphisbaenian.
Saniwa cf. S. sp. Swain Quarry, Carbon County, Wyoming.[18] 2 trunk vertebrae (AMNH 15960 & 16003).[18] A varanid.
Swainiguanoides S. milleri Swain Quarry, Carbon County, Wyoming.[18] Jaw elements.[18] An iguanid.

Testudines

Testudines reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Atoposemys A. entopteros Montana.[19] Tullock Member.[19] A softshell turtle.
Axestemys A. montinsana PTRM Site V02017, Slope County, North Dakota.[20] Numerous skull, limb & shell fragments.[20] A softshell turtle also found in the Melville & Denver formations.
Cardiochelyon C. rogerwoodi Reis Quarry, Park County, Wyoming.[21] Partial skeleton (YPM PU14671).[21] A kinosternoid formerly thought to be a platysternid.
Cedrobaena C. putorius Cedar Point Quarry, Wyoming.[22] Shell & skull elements.[22] A baenid turtle also found in the Hell Creek Formation.
Hutchemys H. arctochelys Burns Mine, Washoe Area, Carbon County, Montana.[23] Tongue River Member.[23] Multiple shell elements.[23] A softshell turtle.
H. rememdium Fallon County, Montana.[23] Ekalaka Member.[23] A near complete postcranial skeleton (YPM PU 16795) & shell elements.[23] A softshell turtle.
H. sp. Duffy's Ranch, Sweet Grass County, Montana.[23] YPM PU 11566.[23] A softshell turtle.
Ptychogaster P. sp. Princeton Quarry & Reiss Locality, Park County, Wyoming.[17] PU 17794 (fragments of the skull & shell), 14671 & 16443 (shells).[17] A turtle.
Tullochelys T. montanus Montana.[19] Tullock Member.[19] A chelydrid turtle also known from the Hell Creek Formation.

Amphibians

Amphibians reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Amphiuma A. jepseni Park County, Wyoming.[17] PU 14666 (partial vertebral column), 14668 (partial skull) & 16788 (dislocated vertebrae).[17] An aquatic salamander.
Anura Incertae sedis Park County, Wyoming.[17] PU 14662 (distal end of right radioulna), 14663 (proximal end of left radioulna), 14669 (phalanx), 13372 (right maxilla).[17] A frog.
Discoglossidae Undescribed genus & species Park County, Wyoming.[17] Distal end of right humerus (PU 14670).[17] A frog similar to undescribed discoglossid remains from the Hell Creek Formation.[17]
Eorhinophrynus E. sp. Princeton & Fritz quarries, Park County, Wyoming.[17] Humeri & vertebrae.[17] A burrowing toad.
Opisthotriton O. kayi Princeton Quarry, Park County, Wyoming.[17] Multiple specimens.[17] A salamander.
Scapherpeton S. tectum Princeton & Schaff quarries, Park County, Wyoming.[17] PU 20583 (3 broken vertebrae, an atlas, an ilium & a rib) & PU 19500 (a humerus).[17] A salamander.

Fish

Fish reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Acipenseridae Morphotype A Eagle Mine near Bear Creek, Carbon County, Montana.[24] A complete lateral scute (YPM VPPU 17066).[24] A large sturgeon.
Morphotype B Highway Blowout Site, Fallon County, Montana.[24] Tongue River Member.[24] A complete lateral scute (YPM VPPU 16646).[24] A large sturgeon.
Amia A. fragosa Schaff Quarry, Park County, Wyoming.[17] 3 vertebral centra (PU 21174).[17] A bowfin.
Atractosteus A. grandei Bowman County, North Dakota.[25] Lowest Danian strata.[25] A large gar.
Engdahlichthys E. milviaegis Montana.[26] Tullock Member.[26] A fairly small sturgeon.
Polyodon P. tuberculata Montana.[26] Tullock Member.[26] 3 specimens.[26] A paddlefish.

Invertebrates

Bivalves

Bivalves reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Pisidium P. sp. indet. Powder River Basin.[27] Tongue River Member.[27] 8 specimens.[27] A sphaeriid.
P.? sp. indet. Powder River Basin.[27] Tongue River Member.[27] 3 specimens.[27] A sphaeriid.
Plesielliptio P. priscus Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A unionid.
cf. P. priscus Powder River Basin.[27] Tongue River Member.[27] Several specimens.[27] A unionid.
P. silberlingi Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A unionid.
cf. P. silberlingi Powder River Basin.[27] Tongue River Member.[27] 6 specimens.[27] A unionid.
P. sp. indet. Powder River Basin.[27] Tongue River Member.[27] 2 specimens.[27] A unionid.
Sphaeriidae Gen. & sp. indet. Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A sphaeriid.
Sphaerium S. sp. indet. Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A sphaeriid.
S.? sp. indet. Powder River Basin.[27] Tongue River Member.[27] Several specimens.[27] A sphaeriid.
Unionidae Gen. & sp. indet. Powder River Basin.[27] Tongue River Member.[27] 11 specimens.[27] A unionid.

Gastropods

Gastropods reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Acroloxus A.? minutus Powder River Basin.[27] Tongue River Member.[27] 2 specimens.[27] A river limpet.
A. sp. indet. Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A river limpet.
Clenchiella C. n. sp. A Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A clenchiellid.
C. n. sp. A? Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A clenchiellid.
C. cf. C. n. sp. A Powder River Basin.[27] Tongue River Member.[27] 10 specimens.[27] A clenchiellid.
C. sp. indet. Powder River Basin.[27] Tongue River Member.[27] 30 specimens.[27] A clenchiellid.
Hydrobia H. anthonyi Powder River Basin.[27] Tongue River Member.[27] 2 specimens.[27] A hydrobiid.
H. sp. A Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A hydrobiid.
H. cf. H. sp. A Powder River Basin.[27] Tongue River Member.[27] 2 specimens.[27] A hydrobiid.
H. sp. B? Powder River Basin.[27] Tongue River Member.[27] Multiple specimens.[27] A hydrobiid.
H. sp. C? Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A hydrobiid.
H. sp. indet. Powder River Basin.[27] Tongue River Member.[27] Multiple specimens.[27] A hydrobiid.
H.? sp. indet. Powder River Basin.[27] Tongue River Member.[27] 2 specimens.[27] A hydrobiid.
Lioplacodes L. multistriata Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A viviparid.
L. tenuicarinata Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A viviparid.
L. tenuicarinata? Powder River Basin.[27] Tongue River Member.[27] 11 specimens.[27] A viviparid.
L. limneaformis Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A viviparid.
L. sp. indet. Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A viviparid.
L.? sp. indet. Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A viviparid.
Valvata? V.? sp. indet. Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A valvatid.
Viviparus V. raynoldsanus Powder River Basin.[27] Tongue River Member.[27] Numerous specimens.[27] A viviparid.
V. raynoldsanus? Powder River Basin.[27] Tongue River Member.[27] 1 specimen.[27] A viviparid.
V. cf. V. raynoldsanus Powder River Basin.[27] Tongue River Member.[27] 17 specimens.[27] A viviparid.
V. sp. Powder River Basin.[27] Tongue River Member.[27] Multiple specimens.[27] A viviparid.

Plants

Plants reported from the Fort Union Formation
Genus Species Locality Stratigraphic member Material Notes Images
Aesculus A. hickeyi Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves.[28] A horse chestnut.
Amersinia A. obtrullata Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Fruits.[28] A nyssaceaen, may be produced by the same plant as Beringiaphyllum cupanioides.
Beringiaphyllum B. cupanioides Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaf (UF 18969-60464).[28] A nyssaceaen, may be produced by the same plant as Amersinia obtrullata.
Browniea B. serrata Mexican Hat locality & Custer National Forest, Powder River County, Montana.[28][29] Lebo Member & Tongue River Member.[28][29] Leaves showing signs of insect damage.[29] A nyssaceaen.
Cercidiphyllum C. genetrix Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves showing signs of insect damage.[29] A katsura tree.
Cornus C. swingii Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves.[28] A dogwood.
Davidia D. antiqua Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves & fruits.[28] A dove tree.
Cf. Dennstaedtia Cf. D. americana Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] A single specimen of sterile foliage (UF 18969-34532).[28] A fern.
Dicotylophyllum D. hansonium Williston Basin, North Dakota.[30] Tongue River Member.[30] Leaves.[30] A dicot.
D. horsecreekium Williston Basin, North Dakota.[30] Ludlow Member.[30] Leaves.[30] A dicot.
Eostangeria E. pseudopteris Sweetwater County, Wyoming.[31] Upper part of the formation.[31] Multiple specimens.[31] A cycad.
Equisetum E. sp. Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] A single stem (UF 18969-60476A).[28] A horsetail.
"Ficus" "F." artocarpoides Mexican Hat locality.[29] Lebo Member.[29] Leaves with signs of hole feeding and insect mining.[29] A fig-tree.
Glyptostrobus G. europaeus Mexican Hat locality.[29] Lebo Member.[29] Leafy branches.[29] A conifer.
Juglandiphyllites J. glabra Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves with insect damage and probable lepidopteran leaf mines.[29] A member of the walnut family.
Lauraceae Species 1 Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaf with piercing and sucking marks from insects.[29]
Species 2 Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves showing signs of insect damage.[29]
Macginistemon M. mikanoides Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Stamen groups.[28] A platanaceaen.
Macginitiea M. gracilis Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] A fragmentary leaf (UF 18969-38380).[28] A platanaceaen.
M. nascens Williston Basin, North Dakota.[30] Ludlow Member.[30] Leaves.[30] A platanaceaen.
Meliosma M. thriviensis Williston Basin, North Dakota.[30] Ludlow Member.[30] Leaves.[30] A sabiaceaen.
M. vandaelium Williston Basin, North Dakota.[30] Tongue River Member.[30] Multiple leaves.[30] A sabiaceaen.
Nordenskioeldia N. borealis Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Fruit.[28] A trochodendrale.
Paleonelumbo P. macroloba Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves.[29] A nelumbonaceaen.
Paranymphaea P. crassifolia Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves.[29] A nymphaeaceaen.
Phyllites P. demoresii Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves.[28]
Platanus P. raynoldsii Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves showing signs of insect damage.[29] A plane-tree.
P. sp. Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves.[28] A plane-tree.
Polyptera P. manningii Mexican Hat locality, Montana.[29] Lebo Member.[29] Fruits.[29] A member of the walnut family.
"Populus" "P". nebrascensis Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaves showing signs of insect damage.[29] A poplar.
Porosia P. verrucosa Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Fruits.[28] A rutaceaen.
Taxodium T. olrikii Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] [28] A cypress tree.
Ternstromites cf. T. aureavallis Mexican Hat locality, Montana.[29] Lebo Member.[29] Leaf with a gall at the intersection of primary and secondary veins.[29] A theaceaen.
T. paucimissouriensis Williston Basin, North Dakota.[30] Ludlow & Tongue River Members.[30] Leaves.[30] A theaceaen.
Trochodendroides T. genetrix Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] A few leaves.[28] A saxifrage.
Ulmites U. microphylla Custer National Forest, Powder River County, Montana.[28] Tongue River Member.[28] Leaves.[28] An ulmaceaen.
Zizyphoides Z. flabella Mexican Hat locality, Montana & Custer National Forest, Powder River County, Montana.[29][28] Lebo Member & Tongue River Member.[29][28] Leaves showing signs of insect damage.[29] A trochodendrale.

See also

References

  1. ^ a b Wyodak Coal, Tongue River Member of the Fort Union Formation, Powder River Basin, Wyoming: "No-Coal Zones" and Their Effects on Coalbed Methane Production, by Mark Ashley, 2005
  2. ^ Eocene and Paleocene rocks of the southern and central basins, by Robert E. McDonald, in Geologic Atlas of the Rocky Mountain Region, Rocky Mountain Association of Geologists, Denver, CO, 1972: p. 248
  3. ^ Cretaceous and Tertiary coals of the Rocky Mountains and Great Plains regions, by R.M. Flores and T.A. Cross, 1991, in Economic Geology, U.S., Geological Society of America, Decade of North American Geology Series, vol. P-2, p. 547-571.
  4. ^ a b c Clemens, William A. (2018-02-17). "A pantodont (Mammalia) from the latest Puercan North American Land Mammal Age (earliest Paleocene) of the Western Interior, USA". Historical Biology. 30 (1–2): 183–188. doi:10.1080/08912963.2016.1276178. ISSN 0891-2963. S2CID 132830375.
  5. ^ a b c Clemens, W. (January 9, 2015). "(Leptictidae, Mammalia) from the Tullock Member of the Fort Union Formation, Garfield and McCone Counties, Montana, USA". PaleoBios. 32 (1): 1–17. doi:10.5070/P9321025382. S2CID 55974838.
  6. ^ a b c d Johanson, Zerina (November 1996). "New marsupial from the Fort Union Formation, Swain Quarry, Wyoming". Journal of Paleontology. 70 (6): 1023–1031. Bibcode:1996JPal...70.1023J. doi:10.1017/S0022336000038725. ISSN 0022-3360. S2CID 133554548.
  7. ^ 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 Gazin, C. Lewis (1971). "Paleocene primates from the shotgun member of the Fort Union Formation in the Wind River Basin, Wyoming". Proceedings of the Biological Society of Washington. 84: 13–37. ISSN 0006-324X.
  8. ^ a b c d e f g h i j k l Burger, Benjamin J.; Honey, James G. (2008-09-12). "Plesiadapidae (Mammalia, Primates) from the late Paleocene Fort Union Formation of the Piceance Creek Basin, Colorado". Journal of Vertebrate Paleontology. 28 (3): 816–825. doi:10.1671/0272-4634(2008)28[816:pmpftl]2.0.co;2. ISSN 0272-4634. S2CID 128913932.
  9. ^ a b c d e f g h i Wilson Mantilla, Gregory P.; Chester, Stephen G. B.; Clemens, William A.; Moore, Jason R.; Sprain, Courtney J.; Hovatter, Brody T.; Mitchell, William S.; Mans, Wade W.; Mundil, Roland; Renne, Paul R. (2021). "Earliest Palaeocene purgatoriids and the initial radiation of stem primates". Royal Society Open Science. 8 (2): 210050. Bibcode:2021RSOS....810050W. doi:10.1098/rsos.210050. ISSN 2054-5703. PMC 8074693. PMID 33972886.
  10. ^ a b c Burger, Benjamin John (2013-10-29). "A new species of the archaic primate Zanycteris from the late Paleocene of western Colorado and the phylogenetic position of the family Picrodontidae". PeerJ. 1: e191. doi:10.7717/peerj.191. ISSN 2167-8359. PMC 3817582. PMID 24255808.
  11. ^ a b c d e f g h i O'Leary, Maureen A.; Rose, Kenneth D. (1995-05-12). "New mesonychian dentitions from the Paleocene and Eocene of the Bighorn Basin, Wyoming". Annals of the Carnegie Museum. 64 (2): 147–172. doi:10.5962/p.215127. ISSN 0097-4463. S2CID 89955337.
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