U.S. Department of the Interior Open-File Report 2015–1087 U.S. Geological Survey Pamphlet accompanies map
MONTANA WYOMING WYOMING UTAH 116° 110° 104° Table 1. Section number, geographic area, cadastral locations, nearby locality, and principal sources of data. 135 miles 108 miles 114 miles 136 miles EXPLANATION A Section Geographic area Principal sources of data 49° CANADA A' 72 miles Cadastral location(s) Nearby locality number UNITED STATES 6 A Conglomerate or breccia Disconformity—In strata 1 East Glacier Park 102 miles Cumberland Gap area—Lincoln County, Wyo. 1 Southeastern Glacier National Park and adjacent areas, Mont. T. 29–32 N., R. 11–13 W. East Glacier Park Rice and Cobban, 1977 Disconformity—In stratigraphic nomenclature Sandstone * * * * 5 Paleocene 2 Drummond area, Mont. T. 10–11 N., R. 10–13 W. Drummond Gwinn, 1961and 1965 Tentative correlation of disconformities MONTANA Sandstone with shale partings Northern Jackson Hole—Teton County, Wyo. Fort Union Formation 3 Pioneer Mountains, Lima Peaks, Te ndoy Mountains, Mont. T. 4–15 S., R. 8–14 W. Lima Dyman, Porter, and others, 1995 2 Drummond Stage boundary—In column for stages; queried where approximate FEET 4 Cinnabar Mountain area, Mont. T. 8 S., R. 7 E. Gardiner Tysdal and others, 1990; Fraser and others, 1969 Sandstone, calcareous Late Cretaceous and Paleocene 0 Correlation of stage boundaries 2 * * * 88 miles 5 Northern Jackson Hole, Wyo. T. 42–45 N., R. 112–114 W. Jackson Love and others, 1948; Love, 1956 4 Nonmarine strata Pinyon Conglomerate 3 Gardiner Siltstone Drummond area—Granite and Powell Counties, Mont. Lima FEET 6 Cumberland Gap area, Wyo. T. 19–20 N., R. 116–117 W. Kemmerer Cobban and Reeside, 1952; Merewether and others, 1984 45° 0 Oligocene clays * * * Shale Marine shale 7 Coalville area, Utah T. 2–3 N., R. 4–6 E. Coalville Ryer, 1977; Merewether and others, 1997 FEET 3 IDAHO Shale with sandstone lenses Marine calcareous shale 0 8 Price area, Utah T. 13–15 S., R. 8–10 E. Price Gardner and Cross, 1994; Anna, 2012 5 Jackson Ostrea Eastern Pioneer Mountains, Lima Peaks, 7 Inoceramus soleniscus 9 Northeastern Grand County, Utah T. 17–21 S., R. 17–24 E. Harley Dome Fouch and others, 1983; Anna, 2012 WYOMING Tendoy Mountains—Beaverhead County, Mont. 500 Shale, calcareous dimidius Fossil in strata and associated zones Coalville area—Summit County, Utah Zones 33, 34 10 Henrieville, Utah T. 37–38 S., R. 1–2 W. Henrieville Dyman and others, 2002; Titus and others, 2005 Scaphites Paleocene 6 Shale, carbonaceous hippocrepis? Lower Tertiary formations Fossil projected to strata and associated zones 11 Yale Point area, Black Mesa, Ariz. 36.5° N., 110° W. Kayenta Repenning and Page, 1956; Beaumont and Dixon, 1965 Zones 52–54 500 Kemmerer Fort Union Formation Anomia cf. Fort Union Formation Limestone Anemia micronema Fossil in strata, associated zones unknown FEET 12 Farmington area, New Mex. T. 27–30 N., R. 10–13 W. Farmington Molenaar and others, 2002 41° fremonti 0 FEET 7 500 * * * 0 NEVADA Coalville Maastrichtian * * * 13 Gallup area, New Mex. T. 16 N., R. 18 W. Gallup Molenaar and others, 1996 Limestone, shaley or sandy Collignoniceras Occurences of earliest middle Turonian fossils and woollgari associated zone that are are used as the datum 1,000 ? Price Zone 29 90 miles 8 9 Bentonite Lioplacodes sp. cf. L. tenuicarinata Tentative correlation of earliest middle Turonian ? Harley Dome UTAH COLORADO Coal fossils (zone 29) Thickness of
1,000 Evanston Maastrichtian sequence omitted Formation 75.02 Ma Tentative absolute age (Ma) 2,500 C Campanian 8 Concealed Thickness of 500 Ginkgo laramiensis * * * 1,000 500 Henrieville sequence omitted Price area—Carbon County, Utah 10
Golden Spike Formation 4,000 1,500 37°
Adaville Formation Paleocene Farmington Harebell Formation Kayenta 11 Maastrichtian ARIZONA 12 Campanian North Horn Formation FEET NEW MEXICO UTAH ARIZONA SCALE 0 0 60 120 MILES Campanian 3,000 13 Gallup 0 60 120 KILOMETERS A' 1,000 1,000 ARIZONA NEW MEXICO 4,500 Figure 1. Map of selected Rocky Mountain States showing locations 2,000 of main outcrop-sections (part) Formation North Horn Maastrichtian * * * Maastrichtian * * * ? 500 192 miles (not to scale) 3,500 1,500 Thickness of ? * * * 1,500 5,000 3,500 sequence omitted 128 miles 2,500 9 Northeastern Grand County, Utah Formation Price River
Santonian 122 miles Paleocene 1,000 4,000 North Horn Formation 78 miles Lazeart FEET 1 Sandstone * * * 2,000 0 Member 10 Glacier National Park area—Glacier County, Mont. 5,500 4,000 Meeteetse Formation ? 3,000 Henrieville area—Garfield and Kane Counties, Utah Paleocene Paleocene 12 ? Farmington area—San Juan County, N. Mex.
Willow Creek Formation 4 (part) Sandstone Castlegate Echo Canyon Conglomerate
Formation Canaan Peak Formation (upper part) North Horn Formation 1,500 Mesaverde FEET Paleocene Cinnabar Mountain area—Park County, Mont. Maastrichtian FEET 4,500 * * * 0 Baculites reesidei? ? 0 Ojo Alamo Sandstone * * * * * * Paleocene Hinshaw 2,500 500 Zone 71 Member FEET UPPER CRETACEOUS 6,000 4,500 Fort Union Formation Campanian 3,500 74.21 Ma 0 FEET * * * 0 * * * Didymoceras cheyennense? Zone 68 Farmington Sandstone Maas- ? trichtian ? Member Campanian 2,000 5,000 Thickness of 500 6,500 sequence omitted 500 Formation Baculites thomi ? 3,000 Price River 1,000 Lenticular sandstone and shale sequence 6,500 Zone 50 Kirtland Shale 5,000 500 4,000 Formation
Blackhawk lower shale member
500 ? Baculites Zone 69 Fruit- compressus ? 2,500 land Maastrichtian 1,000 Form- 1,000 Baculites clinolobatus? 7,000 ation Zone 77 3,500 * * * 1,500 7,000 Thickness Formation Santonian 5,500 Kaiparowits 1,000 4,500 of sequence 75.02 Ma Beaverhead Group 4,500 Scaphites hippocrepis? omitted Exiteloceras jenneyi? Zone 67 Didymoceras stevensoni ? Zone 66
Cliffs Campanian 1,000 Zones 52–54 Pictured St. Mary River and Willow Creek Formations, undivided
Sandstone
Didymoceras mortoni? Zones 64–69 ? Neslen Coaly sequence 75.02 Ma Clioscaphites vermiformis? Zone 47 Formation Star Point Sandstone 3,000 Horsethief Crassostrea wyomingensis Huerfanito Bentonite Bed 75.76 Ma Santonian
part)
Sandstone Shale Lewis Campanian
(upper
1,500 1,500 Oxytoma nebrascana 7,500 Sego Didymoceras nebrascense ? Zone 65 Carten Creek Formation Baculites scotti? Zone 64
Upper part of Sandstone 2,000 Cliff House Ss. Baculites obtusus? Blue Gate Member (upper part) Baculites reesidei Zone 71 7,500 6,000 Zone 57 Landslide Creek Formation Menuites portlocki? Zones 62, 63 Baculites scotti? Zone 64 1,500 Shale Baculites cuneatus Zone 70 5,000 Baculites scotti ? Zone 64 Campanian Bearpaw Baculites compressus Zone 69 5,000 Buck Tongue 75.96 Ma 1,500 Clioscaphites Desmoscaphites bassleri? Baculites perplexus Zone 61 Shale UPPER CRETACEOUS Exiteloceras jenneyi? Zone 67 Santonian Zone 50 Baculites reduncus? Zone 63 Mancos Trapa microphylla vermiformis? part) ? Zone 47 Baculites thomi? (middle
Lewis Shale Baculites 3,500 Zone 50 Castlegate Baculites asperiformis? Zone 59 perplexus ? Zone 61
Sandstone Campanian ? 2,000 2,000 8,000 Scaphites depressus? Zone 45 Henefer Formation Baculites maclearni Zone 58
Hilliard Shale Cliff House Baculites asper Zone 45 2,500
8,000 UPPER CRETACEOUS Sandstone
6,500 Campanian 5,500 Baculites obtusus Zone 57 (middle 2,000 Scaphites leei? Zone 51 5,500 part) ? Baculites sp. (weak flank ribs) Zone 56 * * * 2,000 Inoceramus sp. Shurtliff UPPER CRETACEOUS
Bacon Ridge Sandstone Member Scaphites ventricosus Zone 44 Baculites 4,000 Scaphites hippocrepis? Zones 52–54 Coniacian asperiformis ? Zone 59
part)
Shale
Lewis
(lower 2,500 8,500 C Emery 2,500 Desmoscaphites bassleri ? Zone 50 oysters and pelecypods 3,000 Cliff House Ss. 8,500 Sandstone (lower part) 7,000 Member 6,000 Cremnoceramus deformis Prairie Canyon 2,500 6,000 Zones 39–42 Member
Formation 2,500 UptonSandstone Wahweap Brachyceratops montanensis Member Crassatella andrewsi Baculites perplexus? Zone 61 Judd Shale Member 4,500 ?
Two Medicine Formation Two 3,000 UPPER CRETACEOUS 3,000 UPPER CRETACEOUS 9,000 UPPER CRETACEOUS Everts Formation Clioscaphites vermiformis 3,500 9,000 Santonian Zone 47 7,500 6,500 3,000 6,500 Menefee Formation
Santonian 3,000
? Grass Creek Clioscaphites vermiformis? Member 5,000 Zone 47 ? Santonian Scaphites depressus? Zone 45 ? Mancos Shale 3,500 Drip Tank Member 3,500 9,500 Scaphites ventricosus Zone 44 Baculites 4,000 Point 9,500 Cardium pauperculum codyensis? UPPER CRETACEOUS
8,000 Thickness of Zones 44, 45 Lookout 3,500 Volviceramus involutus Zone 44 7,000 Cody Shale sequence omitted Coniacian 7,000 Cataceramus balticus? Zones 52–55 Sandstone 10,000 UPPER CRETACEOUS ? * * * 3,500 * * * Desmoscaphites erdmanni? Zone 49 Clioscaphites choteauensis? Zone 48 Inoceramus frechi Zone 44 Inoceramus lobatus Zones 49–52 Shale Haresiceras Mancos Virgelle Coniacian Scaphites ventricosus? Zone 44 mancosense? Zone 50 13
Zone 52 Eagle Sandstone 5,500 Scaphites hippocrepis I Cremnoceramus Santonian Clioscaphites 11 Santonian Sandstone Inoceramus deformis? deformis Gallup area—McKinley County, N. Mex. Scaphites leei III Zone 51 ? Clioscaphites choteauensis? Zone 48 4,000 vermiformis 4,000 Zones 39–42 10,000 Zones 39–42 Zone 47 Yale Point area, Black Mesa—Northeastern, Ariz. Telegraph Desmoscaphites bassleri Zone 50 4,500 Niobrara Formation Paleocene Scaphites leei II 10,000 Plesielliptio sp. Lower part of Creek Blue Gate Member equivalent Pliocene Formation Scaphites leei I ? 4,000 Clioscaphites vermiformis? Zone 47 7,500 ? Nacimiento Formation Desmoscaphites erdmanni Zone 49 10,500 7,500 Bidahochi Formation Clioscaphites FEET
? Santonian Formation John Henry Member vermiformis? Clioscaphites vermiformis Telegraph FEET 4,000 Straight Cliffs Zone 47 Zone 47 Coniacian 0
UPPER CRETACEOUS Creek ? 0 Baculites codyensis ? Formation Clioscaphites saxitonianus? Zone 46 Coniacian Clioscaphites choteauensis Zone 48 Zones 44, 45 * * * * * * Robulus pseudosecans 6,000 Yale Point
Jens Formation Sandstone Scaphites depressus Zone 45 Cytherella cf. C. kansasensis 4,500 ? Mancos Shale 4,500 10,500 Ostrea coalvillensis Kevin 5,000 Cremnoceramus deformis Coniacian 10,500 Santonian Member Dry Hollow Formation dobrogensis? Zone 40
Cremnoceramus deformis
Member ? UPPER CRETACEOUS 4,500
Shale 8,000 Coniacian Zone 40 Scaphites depresssus Zone 45 Scaphites ventricosus Zone 44 Scaphites depressus? Zone 45 Cremnoceramus dobrogensis ? deformis erectus 8,000 Crevasse Canyon 11,000 Volviceramus involutus Zone 44 Wepo Marias River * * * fossil logs Coniacian Santonian Campanian Zone 39 Cremnoceramus 4,500 Cremnoceramus deformis Zones 39–42 Coniacian Formation deformis dobrogensis? 500
Scaphites preventricosus Zones 39–43 Inoceramus stantoni Zones 44, 45 Coniacian Zone 35 Cremnoceramus deformis dobrogensis Zone 40 Smoky Hollow Member Zone 40 Gallup Inoceramus perplexus? Cremnoceramus deformis? Zones 39–42 Cody Cremnoceramus deformis * * * 500 Cremnoceramus deformis * * * Baculites mariasensis Zone 38 Volviceramus involutus Zone 44 dobrogensis Zone 40 Toreva dobrogensis Zone 40 * * * * Sandstone Inoceramus dimidius? Zones 33, 34 Coniacian Blue Gate Member Shale 6,500 Tibbet Canyon Member Coniacian Cremnoceramus Prionocyclus quadratus Zone 37 Scaphites whitfieldi ? Zone 35 90.51 Ma Cremnoceramus deformis ? deformis erectus, Scaphites warreni Zone 33 Prionocyclus hyatti Zone 31 dobrogensis Zone 40 Scaphites warreni? Zone 33
Scaphites nigricollensis Prionocyclus hyatti? Zone 31 Placenticeras planum Prionocyclus macombi Zone 32 5,000 5,000 Coniacian 11,000 Zone 39 Zone 36 * * * Scaphites whitfieldi? Prionocyclus macombi Zone 32 Cremnoceramus * * * Juana Lopez Member Zone 35 Mytiloides incertus? Dry Hollow Scaphites whitfieldi ? Zone 35 5,500 Prionocyclus hyatti Zone 31 Lopha lugubris
Turonian 11,000 deformis erectus Zone 39 Scaphites warreni? Scaphites nigricollensis Zone 36 Inoceramus sp. Member Scaphites warreni ? Zone 33 * * * Prionocyclus hyatti? Zone 31 Collignoniceras praecox? Zone 30 Formation Inoceramus dimidius Zones 33, 34 5,000 Juana Lopez Member Turonian Prionocyclus hyatti? Zone 31 * * * * 8,500 Ferron Sandstone Prionocyclus hyatti Zone 31 Prionocyclus macombi? Ferdig Scaphites whitfieldi? Zone 32 * * * 11,500 Inoceramus deformis Zone 35 8,500 Oyster Ridge Member Tununk Member Prionocyclus hyatti Zone 31 Spathites aff. chispaensis Member Turonian Prionocyclus hyatti? Zones 39–42 Collignoniceras Sandstone Member * * * *
Turonian ? Prionocyclus hyatti Zone 31 Zone 31 Prionocyclus hyatti? Zone 31 5,000 * * * woollgari Zone 29 Collignoniceras woollgari Zone 29 Turonian 1,000 Actinocamax manitobensis? Zone 29 Actinocamax sp. Oyster Ridge Ss. Mbr. Collignoniceras woollgari Turonian * * * Collignoniceras Collignoniceras Collignoniceras woollgari Zone 29 Collignoniceras woollgari Zone 29 Collignoniceras woollgari Zone 29 Collignoniceras UPPER CRETACEOUS Collignoniceras woollgari Zone 29 Zone 29 1,000 * * * Cone Mbr Mytiloides mytiloides Rhynchostreon suborbiculatum Zones 29, 30, 31 * * * * woollgari Collignoniceras woollgari Zone 29 Coon Spring Sandstone Bed of Tununk Member Inoceramus cuvieri Zone 29 Turonian woollgari?
Turonian Mammites nodosoides Collignoniceras woollgari Zone 29 Zone 28 Turonian Zone 28 Zone 29 Crassostrea soleniscus 7,000 UPPER CRETACEOUS Floweree Mbr Zone 29 woollgari Zone 29 Inoceramus labiatus? Zones 27, 28 Mytiloides mytiloides Zone 28 Turonian Mammites nodosoides Tununk * * * Sciponoceras gracile * * * ? Dakota Bridge Creek Ls Mbr Mancos Shale Pycnodonte newberryi Zone 21 Zone 28 Shale Tropic * * Turonian Turonian Zones 20, 21 Zone 28 5,500 Inoceramus labiatus? Zones 27, 28 Frontier Member 5,500 Mytiloides mytiloides Sciponoceras gracile? 11,500 Allen Sandstone Pycnodonte newberryi? Vascoceras birchbyi Zone 27 Twowells Tongue of Inoceramus prefragilis Crassostrea soleniscus ? 6,000 Calycoceras canitaurinum? Dakota Sandstone 11,500 Formation Hollow Mytiloides kossmati and Cedar Zone 21 Pseudaspidoceras flexuosum? Zone 26 Zone 16 Zones 15, 16 Turonian Pleuriocardia pauperculum Frontier Formation Gymnentome coalvillensis Member Zones 26–27 Ceno- manian Paguate Tongue of Dakota Ss. Whitewater Arroyo Tongue Turonian Mountain 5,500 Anemia fremonti 9,000 Allen Hollow 93.49 Ma Mancos Shale Sciponoceras gracile Zones 20, 21 Sciponoceras gracile? Zones 20, 21 * * * * Pycnodonte newberryi ? ? ? Formation, Sciponoceras gracile Zones 20, 21 Clay Mesa Tongue Dakota Coberly Formation 12,000 oysters Mytiloides mytiloides 9,000 Member Zone 21 Vascoceras diartianum Euomphaloceras septemseriatum? Zone 21 of Mancos Shale Conlinoceras tarrantense? Zone 10 Zone 20 Dakota Cenomanian Sandstone Vaughn Frontier Formation Zone 28 undivided Thickness of Sciponoceras gracile Dakota Metoicoceras defordi? Zone 18 Calycoceras navicularei Cenomanian Sandstone 13,500 5,500 Ceno- ? ? 1,500 Member Zones 20, 21 ? Inoceramus prefragilis Zones 15, 16 manian
Gryphaea newberryi sequence omitted Coalville * * * Form- Dakota Zone 21 ? Member Mytiloides Ceno- 1,500 * * * manian ation 95.97 Ma * * * * * subhercynicus? Dakota ? ? Form- Albian Cenomanian Sandstone 7,500
Frontier Formation Zone 29 Equivalent ation
Mowry Cenomanian * * * Neogastroplites americanus? Zone 7 Unio cf. Mammites nodosoides
? LOWER CRETACEOUS to Cedar 6,000 Shale postbiplicata Zone 28 6,000 Cenomanian 12,000 * * Mountain * * *
Blackleaf Formation 12,000 ? Coalville Member 6,500 Formation Cenomanian
Frontier Formation Pseudaspidoceras flexuoxum 9,500 Zone 26 * * * 6,000 Flood Muddy Sandstone Member Neogastroplites cornutus Zone 5 9,500 LOWER CRETACEOUS Chalk Creek Aptian-Albian Member 14,000 6,000 Member * * * Protelliptio douglassi Mowry Shale Unio reesideanus 2,000 Shale Salix Albian Eopachydiscus marcianus? Zone 1 frontierensis ? 8,000 Thermopolis 6,500 Dunkleberg * * * 12,500 Muddy Sandstone Member 12,500 Member Eopachydiscus marcianus? Zone 1 LOWER CRETACEOUS Aptian-Albian
Brachydontes Cedar Mountain Formation Cenomanian Black shale opolis Shale Therm- 10,000 multilinigerus 10,000 Thickness Table 2. Molluscan fossil zones, informal zone numbers, and radiometric ages for marine strata in the Aptian and Albian Stages (Lower Cretaceous) and Upper Cretaceous stages in the Western Interior of the United States Cloverly Rusty beds [modified from Cobban and others, 2006; Gradstein and others, 2012]
Aptian of sequence Albian Albian Formation Unio cf. U. douglassi Cenomanian 12,000 Kootenai 6,500 LOWER CRETACEOUS * * * Formation
upper Blackleaf Formation 14,500 Thickness of LOWER CRETACEOUS omitted Divisions of Cretaceous time as used in this report1 15,500 sequence omitted ? ? * * * * * * Neogastroplites 8,500 Western Interior Western Interior Age (Ma) Western Interior Western Interior Age (Ma) Western Interior Western Interior Age (Ma) Kootenai Formation americanus Period Stage Age estimates (Ma) Zone 7 Chalk Creek Member ammonite age spans inoceramid age spans ammonite age spans inoceramid age spans ammonite age spans inoceramid age spans LOWER CRETACEOUS 7,000 13,000 Maastrichtian 72–66 Informal zone nos. Neogastroplites SERIES Stages Substages Informal zone nos. SERIES Stages Substages SERIES Informal zone nos. 13,000 cornutus Stages Substages
Shale 83.6±0.2 Aspen 66.0 93.9±0.2 Zone 5 Campanian 84–72 10,500 Desmoscaphites bassleri 50 84.43±0.34 Nigericeras scotti 24 Mytiloides hattini Sphenoceramus lundbreckensis Santonian 86–84 * * * * Desmoscaphites erdmanni 49 Neocardioceras juddii 23 93.32±0.38 Upper Cretaceous 7,000 Eopachydiscus 12,500 93.82±0.30 90–86
Upper Coniacian ? ? marcianus? Cut Bank Sandstone Member Clioscaphites choteauensis Burroceras clydense Zone 1 Jeletzkytes nebrascensis 80 48 22 * * * 16,000 Inoceramus pictus Turonian 94–90 Upper Formation
* * * Bear River Cordiceramus bueltenensis Cenomanian Hoploscaphites nicolleti 79 Clioscaphites vermiformis 47 Euomphaloceras septemseriatum 21 93.68±0.50 Mid Cenomanian 100–94 7,500 Albian 13,500 * * * Hoploscaphites birkelundae 78 Clioscaphites saxitonianus 46 Cladoceramus undulatoplicatus Vascoceras diartianum 20 93.99±0.72 Albian 113–100 Low
86.3±0.5 Upper Lower Cretaceous Magadiceramus crenelatus Ostrea sp. Baculites clinolobatus “Inoceramus” balchii 69.59±0.36 Scaphites depressus 45 87.14±0.39 Dunveganoceras conditum 19 Aptian 126–113 11,000 77 Up
Cenomanian Magadiceramus subquadratus
Maastrichtian 1 Group Volviceramus involutus Dunveganoceras Metoicoceras Ages were assigned mainly by means of associated molluscan fossils and the molluscan fossil zones of Cobban and others (2006); and Gannett 13,000 Baculites grandis 76 Trochoceramus radiosus 70.00±0.45 Scaphites ventricosus 44 18 Inoceramus ginterensis Gradstein and others (2012); Singer and others, written commun., 2012. Fossils of zone 29 (mainly Collignoniceras woollgari) in the ? Mid Volviceramus koeneni albertense defordi middle Turonian (Cobban and Hook, 1979; Cobban, 1991) provide the stratigraphic datum for the cross section. LOWER CRETACEOUS Vaughn Aptian 75 “Inoceramus” incurvus 43 “Inoceramus” gibbosus Dunveganoceras problematicum 16,500 Member * * * Spring Canyon Member Lower 17 Taft Hill Baculites baculus Cremnoceramus Cremnoceramus Member Neogastroplites americanus ? 74 Endocostea typica 42 88.55±0.59 Dunveganoceras pondi 16 Zone 7 deformis deformis crassus crassus 94.71±0.49 72.1±0.2 Inoceramus prefragilis
14,000 Coniacian Santonian Inoceramus comancheanus ? Zone 2 Longwall Sandstone Member Baculites eliasi 73 “Inoceramus” redbirdensis 71.98±0.31 Scaphites preventricosus 41 Cremnoceramus crassus inconstans Plesiacanthoceras wyomingense 15 Neogastroplites cornutus Lower 11,500 Aspen Shale Cremnoceramus waltersdorfensis Acanthoceras amphibolum Zone 5 Baculites jenseni Cenomanian 14 Inoceramus rutherfordi 94.96±0.50 72 40 hannoverensis * * * Lioplacodes stachei attenuata “Inoceramus” oblongus Lioplacodes stachei inflatus Blackleaf Formation Blackleaf Formation 13,500 Baculites reesidei 71 72.94±0.45 39 Cremnoceramus deformis erectus Acanthoceras bellense 13 Inoceramus arvanus
Blackleaf Formation Blackleaf Formation 89.8±0.3 17,000 Acanthoceras muldoonense Baculites cuneatus 70 Scaphites mariasensis 38 Cremnoceramus waltersdorfensis Middle 12 Albian Acanthoceras granerosense Baculites compressus 69 “Inoceramus” altus 73.52±0.39 Prionocyclus germari 37 Mytiloides scupini 11 Inoceramus macconnelli Upper
14,500 (part) UPPER CRETACEOUS Scaphites nigricollensis Mytiloides incertus Conlinoceras tarrantense ? Didymoceras cheyennense 68 74.67±0.15 Upper 36 10 95.73±0.61 Inoceramus comancheanus Zone 2 Eopachydiscus marcianus? Zone 1 Inoceramus dakotensis Exiteloceras jenneyi 67 75.08±0.11 Scaphites whitfieldi 35 Inoceramus perplexus Flood Sphaeroceramus pertenuiformis (Gap in biostratigraphic record) 9 14,000 Thickness Member Didymoceras stevensoni 66 Prionocyclus ferronensis 34 17,000 of sequence Inoceramus dimidius 17,500 omitted Neogastroplites maclearni Didymoceras nebrascense 65 75.19±0.28 Scaphites warreni 33 8 97.17±0.69? Flood (part) UPPER CRETACEOUS Member 75.56±0.11 Prionocyclus macombi Neogastroplites americanus Baculites scotti 64 32 Inoceramus aff. dimidius 90.21±0.54 Lower 7 LOWER CRETACEOUS 15,000 75.84±0.26 Kelvin Formation Aptian--Albian
Albian “Inoceramus” tenuilineatus Prionocyclus hyatti 31 Neogastroplites muelleri 6 63 Middle Inoceramus howelli 90. 51±0.45 * * * Baculites reduncus Turonian LOWER CRETACEOUS Any use of trade, firm, or product names is for descriptive purposes only and does not imply Reesidella montanensis Collignoniceras praecox 30 Inoceramus n. sp. Neogastroplites cornutus 98.75±0.13 Baculites gregoryensis 62 5 endorsement by the U.S. Government. Eopachydiscus marcianus ? Zone 1 Collignoniceras Actinocamax Mytiloides hercynicus ? 17,500 Baculites perplexus 61 woollgari manitobensis 29 Mytiloides subhercynicus Neogastroplites haasi 4 99.3±0.13
UPPER CRETACEOUS (part) UPPER CRETACEOUS Publishing support provided by: * * * * 18,000 100.5±0.4 Mammites nodosoides 28 Mytiloides mytiloides Denver Publishing Service Center Middle Baculites sp. (smooth) 60 Cataceramus subcompressus 3 Inoceramus bellvuensis Edit and digital layout by L.J. Binder Manuscript approved for publication May 1, 2015 Vascoceras birchbyi 27 93.48±0.58 15,500 Baculites asperiformis 59 2 Inoceramus commancheanus * * * Mytiloides kossmati To learn about the USGS and its information products visit Pseudaspidoceras flexuosum Albian http://www.usgs.gov/
Lower 26 Baculites maclearni 58 Eopachydiscus marcianus 1 104 ? Campanian 1-888-ASK-USGS LOWER CRETACEOUS Watinoceras devonense 25 Mytiloides puebloensis 93.19±0.42 Kootenai Formation Baculites obtusus 57 “Inoceramus” azerbaydjanensis 80.58±0.55 Composite Biostratigraphic Outcrop Sections for Cretaceous Formations 93.9±0.2 For more information concerning this publication, contact: Center Director, USGS Central Energy Resources Science Center Aptian 18,500 18,000 Baculites sp. (weak flank ribs) 56 Box 25046, Mail Stop 939 Kootenai Formation Aptian (303) 236-1647 Baculites sp. (smooth) 55 Along a South-Trending Transect From Northwestern Montana to Northwestern New Mexico Or visit the Central Energy Resources Science Center Web site at: http://energy.usgs.gov/ Aptian (part) 16,000 Scaphites hippocrepis lll 54 (part) LOWER CRETACEOUS Cataceramus balticus Digital files availailable at http://dx.doi.org/10.3133/ofr20151087 or ? ? Scaphites hippocrepis ll 81.86±0.36 http://pubs.usgs.gov/of/2015/1087 * * * By Lower 53 * * * ? ? ? Scaphites hippocrepis l 52 Suggested citation: Merewether, E.A., and McKinney, K.C., 2015, Chronostratigraphic cross E. A. Merewether and K.C. McKinney section of Cretaceous formations in western Montana, western Wyoming, eastern Utah, ISSN 2331-1258 (online) Scaphites leei lll 51 Sphenoceramus lundbreckensis northeastern Arizona, and northwestern New Mexico, U.S.A.: U.S. Geological Survey Morrison Formation 2015 83.6±0.2 http://dx.doi.org/10.3133/ofr20151087 Open-File Report 2015–1087, 10 p. 1 sheet, http://dx.doi.org/10.3133/ofr20151087.