1704:
2266:
1086:
810:
1323:
2298:
512:
412:
3137:
2837:
1850:
834:
2343:
880:
2375:
1069:
519:
419:
2313:
591:
582:
573:
564:
555:
546:
537:
528:
491:
482:
473:
464:
455:
446:
437:
428:
2359:
613:
2328:
2281:
138:
2238:
2252:
853:(K-Pg), which defines the end of the Cretaceous period and has been dated to 66 ± 0.07 Ma old. The 90 metres (300 ft) thickness of the formation is estimated to have been deposited in about 2 million years. Fauna characteristic of the Hell Creek (Lancian land vertebrate age ) are found as high as a few meters below the boundary.
860:, though in some areas (e.g. in North Dakota) the boundary is well within the Ludlow Member, 3 metres (9.8 ft) above the boundary with the Hell Creek in some areas. On the other hand, in some small regions of Montana, the Hell Creek Formation contains the K-Pg boundary, and extends slightly into the Paleogene.
2137:
Many of the modern plant affinities in the Hell Creek
Formation (e.g., those with the prefix "aff." or with quotes around the genus name) may not in reality belong to these genera; instead they could be entirely different plants that resemble modern genera. Therefore, there is some question regarding
1948:
There is evidence of transitional floras in the middle of the Hell Creek
Formation as shown by HCII and HCIII zones. The HCII flora represents a transitional period where taxa from the lower Hell Creek are replaced by the HCIII flora. The diversity of the HCIII zone is very high, and its composition
1330:
A paleo-population study is one of the most difficult of analyses to conduct in field paleontology. Here is the most recent estimate of the proportions of the eight most common dinosaurian families in the Hell Creek
Formation, based on detailed field studies by Horner, Goodwin, and Myhrvold (2011)
1060:
are sometimes found in the riverine Hell Creek
Formation, suggesting that some of these taxa were then, as now, tolerant of fresh water. The "Lancian" fauna is more similar overall phylogenetically to East Asian and Canadian/Alaskan faunas than most Campanian North American faunas. Fossil insects
3241:
Barnet, James S.K.; Littler, Kate; Kroon, Dick; Leng, Melanie J.; Westerhold, Thomas; Röhl, Ursula; Zachos, James C. (February 2018). "A new high-resolution chronology for the late
Maastrichtian warming event: Establishing robust temporal links with the onset of Deccan volcanism".
1586:. This is surprisingly consistent in (1) the two major lag deposits (MOR loc. HC-530 and HC-312) in the Apex sandstone and Jen-rex sand where individual bones were counted and (2) in two thirds of the formation reflected in L3 and U3 records of dinosaur skeletons only.
1561:
The dinosaur collections made over the past decade during the Hell Creek
Project yielded new information from an improved genus-level collecting schema and robust data set that revealed relative dinosaur abundances that were unexpected, and
1295:, strips of black layers deposited in the wetland environment are rich in coal, and a bright band-like layer of sand and mud from the river floodplain accumulated. Many plant species were supported, primarily angiosperms, and less commonly
4101:
3761:, n. gen., n. sp., a spiked, flat-headed pachycephalosaurid dinosaur from the Upper Cretaceous Hell Creek Formation of South Dakota in Lucas, S. G. and Sullivan, R. M., eds., Late Cretaceous vertebrates from the Western Interior"
3421:
DePalma, Robert A.; Smit, Jan; Burnham, David A.; Kuiper, Klaudia; Manning, Phillip L.; Oleinik, Anton; Larson, Peter; Maurrasse, Florentin J.; Vellekoop, Johan; Richards, Mark A.; Gurche, Loren; Alvarez, Walter (23 April 2019).
3164:
Johnson, Kirk R. (2002). "Megaflora of the Hell Creek and lower Fort Union
Formations in the western Dakotas: Vegetational response to climate change, the Cretaceous-Tertiary boundary event, and rapid marine transgression".
1408:
Outcrops sampled by the Hell Creek
Project were divided into three sections: lower, middle and upper slices. The top and bottom sections were the focus of the PLoS One report, and within each portion many remains of
2181:, is probably the richest megaflora assemblage known and the most diverse leaf quarry from the Hell Creek Formation. "TYPE" after the binomial means that it is represented by a type specimen found in the
1264:
environments. Hell Creek is the best studied of these ancient environments. At the time, this region had a subtropical, warm and moist climate. The climate was humid, with flowering plants, conifers,
1623:
footprint, dating from 2007 and described a year later. The largest
Triceratops skull ever discovered, nicknamed 'Dragon King', was found in Glendive, Montana, which is in the Hell Creek Formation.
3142:
3140:
1893:
and Leo Hickey divided it into five zones and described them as HCIa, HCIb, HCIIa, HCIIb, and HCIII as a reflection of floral change through time. For example, the HCIa zone is dominated by
4070:
Bryant, Laurie J. (22 January 1988). "A new genus and species of
Amiidae (Holostei; Osteichthyes) from the Late Cretaceous of North America, with comments on the phylogeny of the Amiidae".
1949:
is more uniform than that of HCII, many of which were rare or absent from the zones below, and some others that used to be common below became rarer in the HCIII zone. These forms include
3564:
Johnson, K.R.; Nichols, D.J.; Hartman, J.H. (2002). "Hell Creek Formation: A 2001 synthesis. The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the northern Great Plains".
1957:
2046:
1895:
4203:, Barnum (1907). "The Hell Creek Beds of the Upper Cretaceous of Montana: their relation to contiguous deposits, with faunal and floral lists and a discussion of their correlation".
1991:
1913:
871:
meteorite impact – such as the chaotic mixing of fossil carcasses and a layer of glass tektites with associated impact impressions – deposited minutes to hours after the impact.
2052:
1997:
1901:
1979:
3667:
Longrich, N (2008). "A new, large ornithomimid from the Cretaceous Dinosaur Park Formation of Alberta, Canada: Implications for the study of dissociated dinosaur remains".
1677:, a large species of dromaeosaur. Fossilized teeth of various troodontids and coelurosaurs are common throughout the Hell Creek Formation; the best known examples include
4342:
4431:
1703:
672:
is a small isolated section of the Hell Creek Formation. In 1966, the Hell Creek Fossil Area was designated as a National Natural Landmark by the National Park Service.
2161:, relatively few plant specimens have been collected from Montana. A few taxa were collected at Brownie Butte Montana by Shoemaker, but most plants were collected from
3522:
Husson, D.; Galbrun, B.; Laskar, J.; Hinnov, L.A.; Thibault, N.; Gardin, S.; Locklair, R.E. (2011). "Astronomical calibration of the Maastrichtian (late Cretaceous)".
1907:
3198:
Johnson, Kirk R.; Nichols, Douglas J.; Attrep, Moses; Orth, Charles J. (August 1989). "High-resolution leaf-fossil record spanning the Cretaceous/Tertiary boundary".
3768:
1963:
3793:
3756:
3475:
Evans, D.C.; Larson, D.W.; Currie, P.J. (2013). "A new dromaeosaurid (Dinosauria: Theropoda) with Asian affinities from the latest Cretaceous of North America".
3111:
Johnson, Kirk R.; Hickey, Leo J. (1990). "Megafloral change across the Cretaceous/Tertiary boundary in the northern Great Plains and Rocky Mountains, U.S.A.".
1985:
1951:
3874:
The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains: An Integrated Continental Record of the End of the Cretaceous
3167:
The Hell Creek Formation and the Cretaceous-Tertiary boundary in the northern Great Plains: An Integrated continental record of the end of the Cretaceous
4205:
4123:
3871:
Pearson, D.A.; Schaefer, T.; Johnson, K.R.; Nichols, D.J.; Hunter, J.P. (2002). Hartman, Joseph Herbert; Johnson, Kirk R.; Nichols, Douglas J. (eds.).
3053:
2970:"Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA"
2690:"Taphonomy and Suggested Structure of the Dinosaurian Assemblage of the Hell Creek Formation (Maastrichtian), Eastern Montana and Western North Dakota"
2545:
1303:. An abundance of fossil leaves are found at dozens of different sites indicating that the area was largely forested by small- to medium-sized trees.
4446:
4366:
2432:
2065:
1780:
2444:
2091:
1973:
1819:
1097:
3713:
Manning, P.L.; Ott, C.; Falkingham, P.L. (2008). "The first tyrannosaurid track from the Hell Creek Formation (Late Cretaceous), Montana, U.S.A".
3076:
Fastovsky, David E.; McSweeney, Kevin (1987). "Paleosols spanning the Cretaceous-Paleogene transition, eastern Montana and western North Dakota".
4441:
2557:
2476:
2468:
1855:
1815:
727:, occurs as a discontinuous but distinct thin marker bedding above and occasionally within the formation, near its boundary with the overlying
2629:
2040:
in the Hell Creek Formation. There is no evidence of fern prairie either. However, there was an extremely high angiosperm diversity — common
1667:, in the Hell Creek-Lance assemblages, which would render these taxa invalid for this formation. This was disproved in a 2015 study, DePalma
411:
2598:
4381:
4376:
3566:
4436:
4401:
4396:
2639:
3287:
Retallack, Gregory J. (November 1994). "A pedotype approach to latest Cretaceous and earliest Tertiary paleosols in eastern Montana".
1236:
were the habitat of various animals, including dinosaurs. A broad coastal plain extended westward from the seaway to the newly formed
2265:
2107:
511:
3613:
Boyd, Clint A.; Brown, Caleb M.; Scheetz, Rodney D.; Clarke, Julia A. (2009). "Taxonomic revision of the basal neornithischian taxa
4421:
4416:
1233:
4386:
4339:
1312:
743:
4099:
Archibald, J.D (1982). "A study of Mammalia and geology across the Cretaceous-Tertiary boundary in Garfield County, Montana".
4406:
4010:
3983:
3956:
3922:
3901:
3882:
3182:
1619:
Fossil footprints of dinosaurs from the Hell Creek Formation are very rare. As of 2017, there is only one find of a possible
1798:
is different from any modern plant community. There are numerous types of leaves, seeds, flowers and other structures from
3892:
Varricchio, D.J (2001). "Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana". In Carpenter, Kenneth (ed.).
2910:
Richardson, T (2008). "Spatial arrangements of fossil species at the Hell Creek formation: Perspectives and conclusions".
4426:
4411:
3524:
2198:
2190:
856:
The K-Pg boundary is generally situated near the contact between the upper Hell Creek and the lower Ludlow member of the
3777:
4324:
4153:
3812:
3623:
2194:
1326:
Pie chart of the time averaged census for large-bodied dinosaurs from the entire Hell Creek Formation in the study area
751:
707:
activity in fluctuating river channels and deltas and very occasional peaty swamp deposits along the low-lying eastern
4253:
4226:
4174:
4148:
2297:
2102:
genera are now extinct. He also believes that, very roughly 80% of the terrestrial plant taxa died out in what is now
260:
3861:
3128:
2186:
2182:
2115:
2094:
as the Hell Creek landscape. The nature of these forests is uncertain because Johnson found that the majority of the
1918:
299:
3582:
A high-resolution megafloral biostratigraphy spanning the Cretaceous-Tertiary boundary in the northern Great Plains
2744:"The Hell Creek Formation, Montana: A Stratigraphic Review and Revision Based on a Sequence Stratigraphic Approach"
1806:
are by far the most diverse and dominant flora of the entire population, about 90 percent, followed by about 5% of
1578:
in U3 and in L3 comprises a greater percentage of the large dinosaur fauna as the second-most abundant taxon after
669:
4334:
2312:
1085:
3805:"An azhdarchid pterosaur cervical vertebra from the Hell Creek Formation (Maastrichtian) of southeastern Montana"
1752:
3331:
3308:
3039:
742:. The specimens displayed are the result of the museum's Hell Creek Project, a joint effort between the museum,
3113:
Global Catastrophes in Earth History; an Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality
3825:
719:
along with palm trees suggests a subtropical and temperate climate, with no prolonged annual cold. The famous
4361:
3097:
850:
1921:. Although the HCIb zone is a very thin layer, about 5 meters of rock, it bears unusually high diversity of
2660:
1771:, and ubiquitous tree leaves. The presence of the simple and lobed leaves, combined with an extremely high
759:
253:
4371:
4231:
4179:
2174:
891:
were found in the Hell Creek Formation. Its location at the changing conjunction of the eastern coast of
4048:
Estes, R.; Berberian, P. (1970). "Paleoecology of a late Cretaceous vertebrate community from Montana".
4391:
4305:
3580:
3394:
3358:
2166:
943:
have also been found in the Hell Creek Formation. The formation has produced impressive assemblages of
755:
4121:(1943). "A study of the troödont dinosaurs with the description of a new genus and four new species".
2006:
818:
4002:
3975:
3948:
3398:
1890:
1547:
783:
747:
645:
2358:
1802:, or flowering plants. The Hell Creek Formation of this layer contains over 300 tablets, of which
3669:
3378:
2374:
1882:
1712:
1229:
1202:
1151:
1037:
896:
712:
3351:
809:
4144:
4118:
237:
3872:
2134:
position were plotted out, the graph would show a spike just above the impact fallout layer).
1322:
1073:
822:
735:
617:
3537:
1031:, including various animal fossils unearthed in the Hell Creek Formation. The most complete
4079:
4035:
Chandrasekharam, A. (1974). "Megafossil flora from the Genesee locality, Alberta, Canada".
3724:
3678:
3632:
3533:
3486:
3435:
3296:
3251:
3207:
3085:
2981:
2792:
2755:
2701:
2621:
2327:
2114:
in the two centimeters of rock that directly overlies the impact fallout layer (the famous
1384:
867:
in North Dakota contains evidence of what is proposed to be a record of the effects of the
857:
846:
728:
182:
154:
4271:
4022:
Christophel, D.C. (1976). "Fossil floras from the Smoky Tower locality, Alberta, Canada".
3556:
Magnetostratigraphy of the Hell Creek and lower Fort Union formations in northeast Montana
2654:
2342:
8:
4307:
The Homer Site: The first triceratops bonebed, Hell Creek Formation, southeastern Montana
4291:
4286:
4258:
3995:
3968:
3941:
3912:
3841:
3477:
2280:
1835:
1135:
1044:
864:
842:
803:
665:
192:
143:
4083:
3849:
3728:
3682:
3636:
3490:
3439:
3300:
3255:
3211:
3089:
2985:
2759:
2705:
1478:
were also included in the breakdown, but were relatively rare. Other dinosaurs, such as
4340:
Paleobiology Database: MPM locality 3850 (Hell Creek Formation): Maastrichtian, Montana
3829:
3740:
3694:
3648:
3510:
3458:
3423:
3223:
3004:
2969:
2717:
2634:
2506:
2303:
1468:
1360:
1225:
1147:
868:
708:
3804:
3379:"National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)"
4006:
3979:
3952:
3918:
3897:
3878:
3857:
3833:
3744:
3707:
3698:
3690:
3599:"Preliminary Notes on the First Recorded Amber Insects from the Hell Creek Formation"
3598:
3514:
3502:
3463:
3347:
3178:
3124:
3009:
2773:
2550:
1647:
1016:
3652:
1661:
concluded that there is little evidence for more than a single dromaeosaurid taxon,
734:
The world's largest collection of Hell Creek fossils is housed and exhibited at the
4267:
4214:
4132:
4091:
4087:
3821:
3732:
3703:
3686:
3657:
3640:
3541:
3494:
3453:
3443:
3304:
3267:
3259:
3227:
3215:
3170:
3116:
3093:
3054:"Yours for US$ 1.8m or more: 'world's biggest dinosaur' skull on sale in Hong Kong"
2999:
2989:
2763:
2709:
2649:
2644:
1922:
1273:
1253:
771:
739:
629:
4289:, Edward Drinker (1883). "The structure and appearance of a Laramie dinosaurian".
2197:; and so on. The majority of Hell Creek megafloral specimens are collected at the
1849:
833:
770:
The Hell Creek Formation is an intensively studied geological formation of mostly
4346:
4328:
3797:
3115:. Geological Society of America Special Papers. Vol. 247. pp. 433–444.
2994:
2666:
2151:
2095:
1874:
1803:
1732:
1716:
1691:
1566:
age classes previously considered rare. We recognize a much higher percentage of
1529:
1523:
1400:
1344:
1281:
1237:
1221:
1170:
1090:
1024:
1007:
779:
723:-enriched Cretaceous–Paleogene boundary, which separates the Cretaceous from the
641:
380:
364:
33:
2768:
2743:
1873:
The plants of the Hell Creek Formation generally represent angiosperm-dominated
3736:
3545:
3424:"A seismically induced onshore surge deposit at the KPg boundary, North Dakota"
3332:"Fossil Site Reveals Day That Meteor Hit Earth and, Maybe, Wiped Out Dinosaurs"
2365:
1764:
1456:
1439:. In the upper Hell Creek section, for example, the census included twenty two
1376:
1368:
1042:
was retrieved in 2000 from the Hell Creek Formation and widely publicized in a
1002:
966:
292:
4335:
Phillip Bigelow, "Hell Creek life: Fossil Flora & Fauna, a Paleoecosystem"
3498:
3174:
4355:
3752:
2777:
2562:
2489:
2449:
2404:
2080:
2076:
2061:
1934:
1791:
1776:
1641:
1632:
1498:
1480:
1423:
1417:
1352:
1300:
1261:
1214:
1198:
1182:
1115:
998:
987:
944:
899:
led to the preservation of fossils of both marine and terrestrial creatures.
879:
688:
314:
301:
275:
262:
164:
89:
41:
29:
4321:
3448:
4200:
4114:
3845:
3506:
3467:
3013:
2854:
2852:
2587:
2581:
2437:
2415:
2178:
2170:
2162:
2131:
2103:
2084:
2002:
1886:
1878:
1831:
1679:
1673:
1663:
1535:
1510:
1504:
1486:
1474:
1462:
1392:
1336:
1292:
1265:
1020:
912:
795:
791:
778:
rocks in North America, named for exposures studied along Hell Creek, near
657:
653:
390:
342:
338:
1763:. The evidence of the forested environment is overwhelmingly supported by
3661:
3644:
2607:
2461:
2456:
2287:
2157:
Compared to the rich Hell Creek Formation fossil plant localities of the
2041:
1942:
1889:
range from the lower to the upper Hell Creek Formation. For this reason,
1865:
1799:
1772:
1727:
at the time before the sea retreated, and in the wet ground of the dense
1563:
1541:
1411:
1139:
1032:
993:
978:
974:
64:
4154:
Annual Report of the American Museum of Natural History of the Year 1909
3120:
2849:
2688:
White, Paul D.; Fastovsky, David E.; Sheehan, Peter M. (February 1998).
2251:
2237:
1068:
174:
Breien, Little Beaver Creek, Middle Sandstone & Pretty Butte Members
3272:
2721:
2689:
2603:
2523:
2514:
2423:
2318:
2123:
2010:
1930:
1724:
1685:
1636:
1516:
1492:
1277:
1245:
1206:
1174:
1166:
1162:
1123:
982:
932:
900:
716:
696:
684:
612:
109:
74:
3554:
2110:. On other hand, there is a great increase in the abundance of fossil
1232:
that divided western and eastern North America during the Cretaceous.
4218:
3263:
3219:
2591:
2569:
2484:
2410:
2057:
1860:
1839:
1827:
1823:
1558:, were reported as being rare and are not included in the breakdown.
1155:
1127:
1111:
1028:
1012:
970:
948:
908:
904:
892:
775:
700:
633:
233:
229:
215:
114:
58:
37:
4136:
2873:
2825:
2713:
1435:
was just as common, if not slightly more common, than the hadrosaur
4175:"Department of Vertebrate Palaeontology; field expeditions of 1906"
4050:
3040:"How a $ 1.8 million dinosaur skull went from Montana to Hong Kong"
2576:
2538:
2528:
2380:
1968:
1938:
1768:
1728:
1639:
taxa with known body fossils from only older formations, including
1241:
1107:
1057:
1052:, mammal, and pterosaur fossils have also been found. The teeth of
961:
888:
837:
Map of the Hell Creek and Lance Formations in western North America
724:
680:
219:
104:
99:
84:
79:
69:
3755:; Sullivan, R.M.; Porter, V.; Larson, P.; Saulsbury, S.J. (2006).
1751:
grew in the forest understory. On the exposed point bars of large
620:
in eastern Montana – Hell Creek Formation (summer dig season 2009)
3715:
2333:
2158:
2146:
2099:
2087:
2017:
1807:
1795:
1736:
1708:
1653:
1553:
1296:
1257:
1249:
1210:
1178:
1131:
956:
799:
787:
720:
704:
661:
649:
346:
334:
119:
94:
49:
3020:
2498:
2349:
2271:
2257:
2071:
2037:
1843:
1786:
1186:
1159:
1119:
952:
940:
924:
916:
692:
45:
3870:
2858:
2400:
2389:
2140:
2127:
2033:
2029:
2025:
1926:
1756:
1631:
Historically, numerous teeth have been attributed to various
1288:
1213:
was subtropical; there was no cold season and probably ample
1143:
1062:
1053:
920:
676:
241:
137:
4102:
University of California Publications in Geological Sciences
1814:, and others. Compared to today Hell Creek's flora which is
1154:. The Hell Creek Formation, as typified by exposures in the
3309:
10.1130/0016-7606(1994)106<1377:APATLC>2.3.CO;2
2534:
2243:
2119:
2111:
1811:
1760:
1748:
1744:
1740:
1284:
1269:
1194:
1190:
1103:
1089:
The dominant plants of the Hell Creek Formation are mainly
1049:
936:
928:
3856:(2nd ed.). Berkeley: University of California Press.
3751:
2968:
Horner, John R; Goodwin, Mark B; Myhrvold, Nathan (2011).
1197:. The Hell Creek Formation was laid down by streams, on a
636:
rocks in North America, named for exposures studied along
3826:
10.1671/0272-4634(2006)26[192:AAPCVF]2.0.CO;2
3769:
New Mexico Museum of Natural History and Science Bulletin
3521:
2831:
2021:
2009:
was warming during the last 300,000-500,000 years of the
1240:. These formations are composed largely of sandstone and
1228:
represent different sections of the western shore of the
3840:
3420:
3197:
3098:
10.1130/0016-7606(1987)99<66:PSTCTE>2.0.CO;2
2879:
817:
In 1966, the Hell Creek Fossil Area was designated as a
3612:
3240:
1885:. There appears to be floral transitions visible on a
3563:
2967:
2687:
3712:
3026:
1592:
is by far the most common dinosaur at 40% (n = 72),
802:. In Montana, the Hell Creek Formation overlies the
664:. In Montana, the Hell Creek Formation overlies the
3877:. Geological Society of America. pp. 145–167.
2922:
2209:
302 plant morphotypes based on leaf only, including
2173:. Among the localities, the Mud Buttes, located in
849:, and the boundary with the latter occurs near the
4432:Fossiliferous stratigraphic units of North America
4206:Bulletin of the American Museum of Natural History
4124:Bulletin of the American Museum of Natural History
3994:
3967:
3940:
3075:
2700:(1). SEPM Society for Sedimentary Geology: 41–51.
3802:
3474:
2092:mixed deciduous and evergreen broad-leaved forest
1158:area of Montana, has been interpreted as a flat,
841:The Hell Creek Formation in Montana overlies the
4353:
2864:
2005:became rarer. This phenomenon suggests that the
1169:that supported a variety of plants ranging from
813:Dinosaurs and pterosaurs of Hell Creek Formation
4113:
4034:
3428:Proceedings of the National Academy of Sciences
2943:
2894:
2230:278 angiosperms (roughly 92% of all taxa found)
1853:Fossil fruits from the Hell Creek Formation of
1846:meant the climate was warmer and wetter then.
4047:
2195:Smithsonian National Museum of Natural History
3381:. U.S. National Park Service. 1966. p. 1
3110:
2630:Lists of dinosaur-bearing stratigraphic units
628:is an intensively studied division of mostly
3910:
3896:. Indiana University Press. pp. 42–57.
2934:
1917:, and is located 55 to 105 meters below the
1098:Climate across Cretaceous–Paleogene boundary
715:. The climate was mild, and the presence of
590:
581:
572:
563:
554:
545:
536:
527:
518:
490:
481:
472:
463:
454:
445:
436:
427:
418:
4021:
3567:Geological Society of America Special Paper
2952:
1102:It is a series of fresh and brackish-water
1080:
675:It is a series of fresh and brackish-water
3992:
3891:
3330:Broad, William J.; Chang, Kenneth (2019).
3329:
3060:
2909:
2816:
1048:documentary aired in December 2007. A few
4098:
3457:
3447:
3286:
3271:
3003:
2993:
2807:
2767:
2185:collections. "YPM" is the prefix for the
2150:, as two examples, actually lived in the
1431:was the most common in each section, but
895:and the adjacent western shallows of the
16:Geological formation in the United States
4447:Upper Cretaceous Series of North America
4367:Geologic formations of the United States
4149:"Department of Vertebrate Palaeontology"
3803:Henderson, M.D.; Peterson, J.E. (2006).
3666:
2885:
1848:
1702:
1616:both at 1% (n = 2) are relatively rare.
1321:
1084:
1067:
878:
832:
808:
611:
498:Hell Creek Formation (the United States)
4303:
4251:
4227:"Department of Vertebrate Paleontology"
3965:
3606:The Journal of Paleontological Sciences
3596:
3578:
3356:
3163:
3146:
2928:
1715:is represented by angiosperm-dominated
4354:
4143:
4069:
4001:. San Diego: Academic Press. pp.
3974:. San Diego: Academic Press. pp.
3947:. San Diego: Academic Press. pp.
3938:
3552:
3289:Geological Society of America Bulletin
3078:Geological Society of America Bulletin
2843:
2741:
1600:is third at 20% (n = 36), followed by
1313:Paleobiota of the Hell Creek Formation
887:The remains of many animals including
4442:National Natural Landmarks in Montana
4272:10.1038/scientificamerican08011903-87
4199:
3159:
3157:
3155:
2912:International Journal of Paleogeology
2199:Denver Museum of Nature & Science
2191:Denver Museum of Nature & Science
1146:deposits along the low-lying eastern
1076:, the "heart" of Hell Creek Formation
4285:
2126:" (meaning that if the abundance of
1877:of variable diversity, depending on
1671:, when they described the new genus
969:(including the marine reptiles like
4322:Cretaceous Hell Creek Faunal Facies
3525:Earth and Planetary Science Letters
2790:
2215:1 bryophyte (mosses and liverworts)
2189:specimen number; "DMNH" is for the
2122:abundance is commonly referred as "
1739:were present. A great diversity of
1723:The Hell Creek Formation was a low
13:
4382:Cretaceous geology of South Dakota
4377:Cretaceous geology of North Dakota
4072:Journal of Vertebrate Paleontology
4063:
3917:. Academic Press. pp. 1–901.
3813:Journal of Vertebrate Paleontology
3624:Journal of Vertebrate Paleontology
3152:
3027:Manning, Ott & Falkingham 2008
2742:Fowler, Denver (5 November 2020).
1657:. However, in a 2013 study, Evans
1626:
752:University of California, Berkeley
14:
4458:
4437:Paleontology in the United States
4402:Paleogene geology of South Dakota
4397:Paleogene geology of North Dakota
4315:
3911:Currie, P.J.; Padian, K. (1997).
3395:"Hell Creek Project – Wilson Lab"
2016:Johnson claims that there are no
1830:forest. In sharp contrast to the
1306:
985:. Notable dinosaur finds include
3708:10.1111/j.1475-4983.2008.00791.x
3691:10.1111/j.1475-4983.2008.00791.x
2822:U.S. National Park Service, 1966
2373:
2357:
2341:
2326:
2311:
2296:
2279:
2264:
2250:
2236:
1863:), closely related to the genus
1291:in the forests. In northwestern
1126:period and the beginning of the
699:period and the beginning of the
670:Pompeys Pillar National Monument
589:
580:
571:
562:
553:
544:
535:
526:
517:
510:
489:
480:
471:
462:
453:
444:
435:
426:
417:
410:
136:
62:
4422:Natural history of South Dakota
4417:Natural history of North Dakota
4304:Mathews, Joshua Collin (2009).
4254:"A remarkable fossil discovery"
3318:
3280:
3234:
3191:
3104:
3069:
3046:
3032:
2961:
2903:
2640:Cretaceous-Paleogene formations
874:
202:50–100 m (160–330 ft)
4092:10.1080/02724634.1988.10011669
3579:Johnson, Kirk Richard (1989).
2784:
2735:
2681:
2321:indicate a hotter paleoclimate
1818:, then Hell Creek's flora was
1404:1% (represented only by teeth)
1396:1% (represented only by teeth)
1244:which have been attributed to
1122:(respectively, the end of the
765:
695:(respectively, the end of the
598:Hell Creek Formation (Montana)
142:Exposure in the badlands near
1:
4387:Cretaceous geology of Wyoming
3914:The Encyclopedia of Dinosaurs
2675:
2205:Overview (from Johnson, 2002)
1272:in the swamps, and conifers,
1150:fronting the late Cretaceous
1061:from inclusions found within
851:Cretaceous-Paleogene boundary
711:fronting the late Cretaceous
501:Show map of the United States
4407:Paleogene geology of Wyoming
3359:"The Day the Dinosaurs Died"
2995:10.1371/journal.pone.0016574
2661:Lopez de Bertodano Formation
2053:Leepierceia preartocarpoides
1998:Leepierceia preartocarpoides
1902:Leepierceia preartocarpoides
1834:today, the presence of many
1317:
760:University of North Carolina
293:Approximate paleocoordinates
7:
4232:The American Museum Journal
4180:The American Museum Journal
2769:10.3390/geosciences10110435
2615:
2392:of the Hell Creek Formation
1741:herbaceous flowering plants
1596:is second at 24% (n = 44),
786:stretches over portions of
648:stretches over portions of
10:
4463:
4427:Natural history of Wyoming
4412:Natural history of Montana
4252:Beasley, Walter L (1903).
4147:, Henry Fairfield (1910).
3737:10.2110/palo.2008.p08-030r
3546:10.1016/j.epsl.2011.03.008
2795:. Montana State University
1967:, and many members of the
1958:"Dryophyllum" tennessensis
1310:
1280:plants, high diversity of
1220:The Hell Creek Formation,
1142:and very occasional peaty
1095:
828:
756:University of North Dakota
4037:Palaeontographica, Abt. A
4024:Palaeontographica, Abt. B
3776:: 331–354. Archived from
3499:10.1007/s00114-013-1107-5
3357:Preston, Douglas (2019).
3175:10.1130/0-8137-2361-2.329
2047:"Dryophyllum" subfalcatum
1896:"Dryophyllum" subfalcatum
819:National Natural Landmark
404:
396:
386:
375:
370:
360:
352:
330:
291:
252:
247:
225:
211:
206:
198:
188:
178:
170:
160:
150:
135:
28:
23:
3993:Breithaupt, B.H (1997).
3894:Mesozoic Vertebrate Life
3852:, Halszka, eds. (2004).
3597:DePalma, Robert (2010).
3553:LeCain, Rebecca (2010).
3399:University of Washington
2793:"Paradise in Hell Creek"
1698:
1556:(more likely Pectinodon)
1134:activity in fluctuating
1081:Depositional environment
1035:dinosaur ever found, an
748:University of Washington
744:Montana State University
616:Paleontological camp of
4345:4 February 2012 at the
4327:24 January 2007 at the
4119:Schlaikjer, Erich Maren
3538:2011E&PSL.305..328H
3449:10.1073/pnas.1817407116
1992:"Celastrus" taurenensis
1964:Liriodendrites bradacii
1914:"Celastrus" taurenensis
1883:sedimentary environment
1794:, and several types of
1713:Milwaukee Public Museum
1570:than previous surveys.
1524:Parasaurolophus walkeri
1203:Western Interior Seaway
1152:Western Interior Seaway
897:Western Interior Seaway
713:Western Interior Seaway
4331:provides a faunal list
3966:Lofgren, D.F. (1997).
2090:. This represents the
2003:cupressaceous conifers
1870:
1720:
1327:
1201:along the edge of the
1093:
1077:
959:(including the lizard
884:
838:
814:
621:
3939:Eberth, D.A. (1997).
2625:(with link directory)
2060:— along with extinct
1856:Spinifructus antiquus
1852:
1707:Detail of Hell Creek
1706:
1325:
1114:deposited during the
1088:
1074:Hell Creek State Park
1071:
1011:, a variety of small
882:
836:
823:National Park Service
812:
762:which began in 1998.
736:Museum of the Rockies
687:deposited during the
618:Museum of the Rockies
615:
4362:Hell Creek Formation
3970:Hell Creek Formation
3796:17 July 2011 at the
3662:10.1671/039.029.0328
3645:10.1671/039.029.0328
2870:Johnson et al., 2002
2622:List of fossil sites
2118:). This increase in
1986:Marmarthia trivialis
1980:"Ficus" planicostata
1859:of the palm family (
1385:Pachycephalosauridae
858:Fort Union Formation
847:Fort Union Formation
729:Fort Union Formation
626:Hell Creek Formation
183:Fort Union Formation
155:Geological formation
24:Hell Creek Formation
4292:American Naturalist
4259:Scientific American
4084:1988JVPal...7..349B
3759:Dracorex hogwartsia
3729:2008Palai..23..645M
3683:2008Palgy..51..983L
3637:2009JVPal..29..758B
3491:2013NW....100.1041E
3478:Naturwissenschaften
3440:2019PNAS..116.8190D
3301:1994GSAB..106.1377R
3256:2018Geo....46..147B
3212:1989Natur.340..708J
3121:10.1130/SPE247-p433
3090:1987GSAB...99...66F
2986:2011PLoSO...616574H
2880:DePalma et al. 2019
2859:Pearson et al. 2002
2760:2020Geosc..10..435F
2706:1998Palai..13...41W
2227:1 ginkgo (uncommon)
2187:Yale-Peabody Museum
2183:Yale-Peabody Museum
2138:whether the modern
2116:K-Pg boundary layer
1952:Elatides longifolia
1919:K-Pg boundary layer
1775:diversity, extinct
1731:, the diversity of
1608:at 5% (n = 9), and
1167:subtropical climate
1045:National Geographic
903:include dinosaurs,
843:Fox Hills Formation
804:Fox Hills Formation
666:Fox Hills Formation
601:Show map of Montana
311: /
272: /
193:Fox Hills Formation
144:Fort Peck Reservoir
30:Stratigraphic range
4372:Cretaceous Montana
3336:The New York Times
2832:Husson et al. 2011
2635:Morrison Formation
2507:Ginkgo adiantoides
2007:global temperature
1929:plants, including
1871:
1721:
1610:Pachycephalosaurus
1469:Pachycephalosaurus
1361:Hypsilophodontidae
1328:
1226:Scollard Formation
1205:. The presence of
1165:with a relatively
1148:continental margin
1094:
1078:
885:
845:and underlies the
839:
815:
709:continental margin
622:
4392:Paleogene Montana
4012:978-0-122-26810-6
3985:978-0-122-26810-6
3958:978-0-122-26810-6
3924:978-0-122-26810-6
3903:978-0-253-33907-2
3884:978-0-8137-2361-7
3485:(11): 1041–1049.
3434:(17): 8190–8199.
3401:. 2017. p. 1
3295:(11): 1377–1397.
3206:(6236): 708–711.
3184:978-0-8137-2361-7
2791:Boswell, Evelyn.
2655:Lefipán Formation
2551:Cercidiphyllaceae
2130:as a function of
2011:Cretaceous period
1908:"Vitis" stantonii
1648:Saurornitholestes
1621:Tyrannosaurus rex
1017:pachycephalosaurs
955:, mammals, fish,
610:
609:
4454:
4311:
4300:
4282:
4280:
4278:
4248:
4246:
4244:
4222:
4196:
4194:
4192:
4170:
4168:
4166:
4140:
4110:
4095:
4059:
4044:
4031:
4016:
4000:
3989:
3973:
3962:
3946:
3935:
3933:
3931:
3907:
3888:
3867:
3837:
3809:
3792:
3790:
3788:
3782:
3765:
3748:
3702:
3656:
3609:
3603:
3586:
3575:
3560:
3549:
3518:
3471:
3461:
3451:
3410:
3408:
3406:
3390:
3388:
3386:
3374:
3372:
3370:
3346:
3344:
3342:
3313:
3312:
3284:
3278:
3277:
3275:
3264:10.1130/G39771.1
3238:
3232:
3231:
3220:10.1038/340708a0
3195:
3189:
3188:
3161:
3150:
3144:
3135:
3134:
3108:
3102:
3101:
3073:
3067:
3064:
3058:
3057:
3056:. 25 April 2015.
3050:
3044:
3043:
3042:. 23 April 2015.
3036:
3030:
3024:
3018:
3017:
3007:
2997:
2965:
2959:
2956:
2950:
2949:Breithaupt, 1997
2947:
2941:
2938:
2932:
2926:
2920:
2919:
2907:
2901:
2898:
2892:
2889:
2883:
2877:
2871:
2868:
2862:
2856:
2847:
2841:
2835:
2829:
2823:
2820:
2814:
2811:
2805:
2804:
2802:
2800:
2788:
2782:
2781:
2771:
2739:
2733:
2732:
2730:
2728:
2685:
2650:Ferris Formation
2645:Denver Formation
2546:Trochodendriodes
2377:
2361:
2345:
2330:
2315:
2300:
2283:
2268:
2254:
2240:
2193:; "USNM" is for
1875:riparian forests
1790:, many types of
1695:, respectively.
1604:at 8% (n = 15),
1091:flowering plants
883:Hell Creek fauna
772:Upper Cretaceous
740:Bozeman, Montana
630:Upper Cretaceous
602:
593:
592:
584:
583:
575:
574:
566:
565:
557:
556:
548:
547:
539:
538:
530:
529:
521:
520:
514:
502:
493:
492:
484:
483:
475:
474:
466:
465:
457:
456:
448:
447:
439:
438:
430:
429:
421:
420:
414:
326:
325:
323:
322:
321:
316:
312:
309:
308:
307:
304:
287:
286:
284:
283:
282:
277:
273:
270:
269:
268:
265:
140:
131:
61:
21:
20:
4462:
4461:
4457:
4456:
4455:
4453:
4452:
4451:
4352:
4351:
4347:Wayback Machine
4329:Wayback Machine
4318:
4276:
4274:
4242:
4240:
4225:
4190:
4188:
4173:
4164:
4162:
4066:
4064:Further reading
4013:
3997:Lance Formation
3986:
3959:
3929:
3927:
3925:
3904:
3885:
3864:
3807:
3798:Wayback Machine
3786:
3784:
3783:on 17 July 2011
3780:
3763:
3723:(10): 645–647.
3601:
3404:
3402:
3393:
3384:
3382:
3377:
3368:
3366:
3340:
3338:
3321:
3316:
3285:
3281:
3239:
3235:
3196:
3192:
3185:
3162:
3153:
3145:
3138:
3131:
3109:
3105:
3074:
3070:
3065:
3061:
3052:
3051:
3047:
3038:
3037:
3033:
3025:
3021:
2966:
2962:
2957:
2953:
2948:
2944:
2939:
2935:
2927:
2923:
2908:
2904:
2899:
2895:
2890:
2886:
2878:
2874:
2869:
2865:
2857:
2850:
2842:
2838:
2830:
2826:
2821:
2817:
2812:
2808:
2798:
2796:
2789:
2785:
2740:
2736:
2726:
2724:
2714:10.2307/3515280
2686:
2682:
2678:
2667:Tremp Formation
2618:
2613:
2568:Laurel family (
2495:
2433:Platyspiroxylon
2384:
2378:
2369:
2362:
2353:
2346:
2337:
2331:
2322:
2316:
2307:
2301:
2290:
2284:
2275:
2269:
2260:
2255:
2246:
2241:
2152:Late Cretaceous
2066:Nilssoniocladus
1820:hardwood forest
1781:Nilssoniocladus
1717:riparian forest
1701:
1692:Richardoestesia
1629:
1627:Eumaniraptorans
1530:Richardoestesia
1401:Dromaeosauridae
1345:Tyrannosauridae
1320:
1315:
1309:
1238:Rocky Mountains
1234:Swampy lowlands
1222:Lance Formation
1100:
1083:
1025:crocodylomorphs
967:marine reptiles
877:
831:
780:Jordan, Montana
776:Early Paleocene
768:
642:Jordan, Montana
632:and some lower
606:
605:
604:
603:
600:
599:
596:
595:
594:
586:
585:
577:
576:
568:
567:
559:
558:
550:
549:
541:
540:
532:
531:
523:
522:
505:
504:
503:
500:
499:
496:
495:
494:
486:
485:
477:
476:
468:
467:
459:
458:
450:
449:
441:
440:
432:
431:
423:
422:
381:Jordan, Montana
365:Williston Basin
319:
317:
313:
310:
305:
302:
300:
298:
297:
280:
278:
274:
271:
266:
263:
261:
259:
258:
146:
130:
129:
128:
127:
122:
117:
112:
107:
102:
97:
92:
87:
82:
77:
72:
67:
56:
55:
53:
38:Early Paleogene
34:Late Cretaceous
17:
12:
11:
5:
4460:
4450:
4449:
4444:
4439:
4434:
4429:
4424:
4419:
4414:
4409:
4404:
4399:
4394:
4389:
4384:
4379:
4374:
4369:
4364:
4350:
4349:
4337:
4332:
4317:
4316:External links
4314:
4313:
4312:
4301:
4283:
4249:
4223:
4197:
4171:
4141:
4111:
4096:
4078:(4): 349–361.
4065:
4062:
4061:
4060:
4045:
4032:
4019:
4018:
4017:
4011:
3990:
3984:
3963:
3957:
3943:Edmonton Group
3923:
3908:
3902:
3889:
3883:
3868:
3862:
3854:The Dinosauria
3838:
3820:(1): 192–195.
3800:
3749:
3710:
3677:(1): 983–996.
3664:
3631:(3): 758–770.
3615:Thescelosaurus
3610:
3593:
3592:
3588:
3587:
3576:
3561:
3550:
3532:(3): 328–340.
3519:
3472:
3417:
3416:
3412:
3411:
3391:
3375:
3363:The New Yorker
3354:
3326:
3325:
3320:
3317:
3315:
3314:
3279:
3250:(2): 147–150.
3233:
3190:
3183:
3151:
3136:
3129:
3103:
3068:
3059:
3045:
3031:
3019:
2960:
2951:
2942:
2933:
2921:
2902:
2893:
2884:
2872:
2863:
2848:
2836:
2824:
2815:
2806:
2783:
2734:
2679:
2677:
2674:
2673:
2672:
2671:
2670:
2664:
2658:
2652:
2647:
2637:
2632:
2627:
2617:
2614:
2612:
2611:
2602:, sycamore or
2595:
2585:
2573:
2566:
2554:
2542:
2532:
2519:
2511:
2510:
2494:
2493:
2481:
2473:
2465:
2453:
2445:Podocarpoxylon
2441:
2428:
2420:
2419:
2407:
2396:
2395:
2393:
2386:
2385:
2379:
2372:
2370:
2366:Cercidiphyllum
2363:
2356:
2354:
2347:
2340:
2338:
2332:
2325:
2323:
2317:
2310:
2308:
2302:
2295:
2292:
2291:
2285:
2278:
2276:
2270:
2263:
2261:
2256:
2249:
2247:
2242:
2235:
2232:
2231:
2228:
2225:
2222:
2219:
2216:
2124:the fern spike
2081:podocarpaceous
2077:araucariaceous
1974:Bisonia niemii
1767:, rooted gley
1765:petrified wood
1700:
1697:
1628:
1625:
1602:Thescelosaurus
1582:, followed by
1457:Thescelosaurus
1454:The dinosaurs
1406:
1405:
1397:
1389:
1381:
1377:Ankylosauridae
1373:
1369:Ornithomimidae
1365:
1357:
1349:
1341:
1319:
1316:
1311:Main article:
1308:
1307:Fossil content
1305:
1082:
1079:
876:
873:
830:
827:
767:
764:
668:. The site of
608:
607:
597:
588:
587:
579:
578:
570:
569:
561:
560:
552:
551:
543:
542:
534:
533:
525:
524:
516:
515:
509:
508:
507:
506:
497:
488:
487:
479:
478:
470:
469:
461:
460:
452:
451:
443:
442:
434:
433:
425:
424:
416:
415:
409:
408:
407:
406:
405:
402:
401:
398:
394:
393:
388:
384:
383:
377:
373:
372:
368:
367:
362:
358:
357:
354:
350:
349:
332:
328:
327:
295:
289:
288:
276:46.9°N 101.5°W
256:
250:
249:
245:
244:
227:
223:
222:
213:
209:
208:
204:
203:
200:
196:
195:
190:
186:
185:
180:
176:
175:
172:
168:
167:
162:
158:
157:
152:
148:
147:
141:
133:
132:
125:
124:
123:
118:
113:
108:
103:
98:
93:
88:
83:
78:
73:
68:
63:
26:
25:
15:
9:
6:
4:
3:
2:
4459:
4448:
4445:
4443:
4440:
4438:
4435:
4433:
4430:
4428:
4425:
4423:
4420:
4418:
4415:
4413:
4410:
4408:
4405:
4403:
4400:
4398:
4395:
4393:
4390:
4388:
4385:
4383:
4380:
4378:
4375:
4373:
4370:
4368:
4365:
4363:
4360:
4359:
4357:
4348:
4344:
4341:
4338:
4336:
4333:
4330:
4326:
4323:
4320:
4319:
4309:
4308:
4302:
4298:
4294:
4293:
4288:
4284:
4273:
4269:
4265:
4261:
4260:
4255:
4250:
4238:
4234:
4233:
4228:
4224:
4220:
4216:
4212:
4208:
4207:
4202:
4198:
4186:
4182:
4181:
4176:
4172:
4160:
4156:
4155:
4150:
4146:
4142:
4138:
4134:
4130:
4126:
4125:
4120:
4116:
4115:Brown, Barnum
4112:
4108:
4104:
4103:
4097:
4093:
4089:
4085:
4081:
4077:
4073:
4068:
4067:
4057:
4053:
4052:
4046:
4042:
4038:
4033:
4029:
4025:
4020:
4014:
4008:
4004:
3999:
3998:
3991:
3987:
3981:
3977:
3972:
3971:
3964:
3960:
3954:
3950:
3945:
3944:
3937:
3936:
3926:
3920:
3916:
3915:
3909:
3905:
3899:
3895:
3890:
3886:
3880:
3876:
3875:
3869:
3865:
3863:0-520-24209-2
3859:
3855:
3851:
3847:
3843:
3839:
3835:
3831:
3827:
3823:
3819:
3815:
3814:
3806:
3801:
3799:
3795:
3779:
3775:
3771:
3770:
3762:
3760:
3754:
3750:
3746:
3742:
3738:
3734:
3730:
3726:
3722:
3718:
3717:
3711:
3709:
3705:
3700:
3696:
3692:
3688:
3684:
3680:
3676:
3672:
3671:
3670:Palaeontology
3665:
3663:
3659:
3654:
3650:
3646:
3642:
3638:
3634:
3630:
3626:
3625:
3620:
3616:
3611:
3607:
3600:
3595:
3594:
3590:
3589:
3584:
3583:
3577:
3573:
3569:
3568:
3562:
3558:
3557:
3551:
3547:
3543:
3539:
3535:
3531:
3527:
3526:
3520:
3516:
3512:
3508:
3504:
3500:
3496:
3492:
3488:
3484:
3480:
3479:
3473:
3469:
3465:
3460:
3455:
3450:
3445:
3441:
3437:
3433:
3429:
3425:
3419:
3418:
3414:
3413:
3400:
3396:
3392:
3380:
3376:
3364:
3360:
3355:
3353:
3349:
3337:
3333:
3328:
3327:
3323:
3322:
3310:
3306:
3302:
3298:
3294:
3290:
3283:
3274:
3269:
3265:
3261:
3257:
3253:
3249:
3245:
3237:
3229:
3225:
3221:
3217:
3213:
3209:
3205:
3201:
3194:
3186:
3180:
3176:
3172:
3168:
3160:
3158:
3156:
3148:
3143:
3141:
3132:
3130:0-8137-2247-0
3126:
3122:
3118:
3114:
3107:
3099:
3095:
3091:
3087:
3083:
3079:
3072:
3063:
3055:
3049:
3041:
3035:
3028:
3023:
3015:
3011:
3006:
3001:
2996:
2991:
2987:
2983:
2980:(2): e16574.
2979:
2975:
2971:
2964:
2955:
2946:
2940:Lofgren, 1997
2937:
2930:
2925:
2917:
2913:
2906:
2900:Preston, 2019
2897:
2888:
2881:
2876:
2867:
2860:
2855:
2853:
2845:
2840:
2833:
2828:
2819:
2810:
2794:
2787:
2779:
2775:
2770:
2765:
2761:
2757:
2753:
2749:
2745:
2738:
2723:
2719:
2715:
2711:
2707:
2703:
2699:
2695:
2691:
2684:
2680:
2668:
2665:
2662:
2659:
2656:
2653:
2651:
2648:
2646:
2643:
2642:
2641:
2638:
2636:
2633:
2631:
2628:
2626:
2623:
2620:
2619:
2609:
2605:
2601:
2600:
2596:
2593:
2589:
2586:
2583:
2579:
2578:
2574:
2571:
2567:
2564:
2563:Sterculiaceae
2560:
2559:
2555:
2552:
2548:
2547:
2543:
2540:
2536:
2533:
2530:
2526:
2525:
2521:
2520:
2518:
2517:
2516:
2509:
2508:
2504:
2503:
2502:
2501:
2500:
2491:
2490:Araucariaceae
2487:
2486:
2482:
2480:(Taxodiaceae)
2479:
2478:
2474:
2472:(Taxodiaceae)
2471:
2470:
2466:
2463:
2459:
2458:
2454:
2451:
2450:Podocarpaceae
2447:
2446:
2442:
2439:
2435:
2434:
2430:
2429:
2427:
2426:
2425:
2417:
2413:
2412:
2408:
2406:
2402:
2398:
2397:
2394:
2391:
2388:
2387:
2382:
2376:
2371:
2368:
2367:
2360:
2355:
2352:
2351:
2344:
2339:
2335:
2329:
2324:
2320:
2314:
2309:
2305:
2304:Monkey-puzzle
2299:
2294:
2293:
2289:
2282:
2277:
2273:
2267:
2262:
2259:
2253:
2248:
2245:
2239:
2234:
2233:
2229:
2226:
2223:
2220:
2217:
2214:
2213:
2212:
2210:
2206:
2202:
2200:
2196:
2192:
2188:
2184:
2180:
2176:
2175:Bowman County
2172:
2168:
2164:
2160:
2155:
2153:
2149:
2148:
2143:
2142:
2135:
2133:
2132:stratigraphic
2129:
2125:
2121:
2117:
2113:
2109:
2108:K-Pg boundary
2105:
2101:
2097:
2093:
2089:
2086:
2085:cupressaceous
2082:
2078:
2074:
2073:
2068:
2067:
2063:
2059:
2055:
2054:
2049:
2048:
2043:
2039:
2035:
2031:
2027:
2023:
2019:
2014:
2012:
2008:
2004:
2000:
1999:
1994:
1993:
1988:
1987:
1982:
1981:
1976:
1975:
1970:
1966:
1965:
1960:
1959:
1954:
1953:
1946:
1944:
1940:
1936:
1935:Ranunculaceae
1932:
1928:
1924:
1920:
1916:
1915:
1910:
1909:
1905:
1903:
1898:
1897:
1892:
1888:
1887:stratigraphic
1884:
1881:position and
1880:
1879:stratigraphic
1876:
1868:
1867:
1862:
1858:
1857:
1851:
1847:
1845:
1841:
1838:taxa such as
1837:
1836:thermophilous
1833:
1829:
1825:
1821:
1817:
1813:
1809:
1805:
1801:
1797:
1793:
1789:
1788:
1783:
1782:
1778:
1774:
1770:
1766:
1762:
1758:
1755:, there were
1754:
1753:river systems
1750:
1746:
1742:
1738:
1734:
1730:
1726:
1718:
1714:
1710:
1705:
1696:
1694:
1693:
1688:
1687:
1682:
1681:
1676:
1675:
1670:
1666:
1665:
1660:
1656:
1655:
1650:
1649:
1644:
1643:
1642:Dromaeosaurus
1638:
1634:
1633:Dromaeosaurid
1624:
1622:
1617:
1615:
1611:
1607:
1603:
1599:
1598:Edmontosaurus
1595:
1594:Tyrannosaurus
1591:
1587:
1585:
1584:Edmontosaurus
1581:
1577:
1576:Edmontosaurus
1573:
1572:Tyrannosaurus
1569:
1568:Tyrannosaurus
1565:
1559:
1557:
1555:
1550:
1549:
1548:Leptorhynchos
1544:
1543:
1538:
1537:
1532:
1531:
1526:
1525:
1520:
1518:
1513:
1512:
1507:
1506:
1501:
1500:
1499:Struthiomimus
1495:
1494:
1489:
1488:
1483:
1482:
1481:Sphaerotholus
1477:
1476:
1471:
1470:
1465:
1464:
1459:
1458:
1452:
1450:
1449:Edmontosaurus
1446:
1445:Tyrannosaurus
1442:
1438:
1437:Edmontosaurus
1434:
1433:Tyrannosaurus
1430:
1426:
1425:
1424:Tyrannosaurus
1420:
1419:
1418:Edmontosaurus
1414:
1413:
1403:
1402:
1398:
1395:
1394:
1390:
1387:
1386:
1382:
1379:
1378:
1374:
1371:
1370:
1366:
1363:
1362:
1358:
1355:
1354:
1353:Hadrosauridae
1350:
1347:
1346:
1342:
1339:
1338:
1334:
1333:
1332:
1324:
1314:
1304:
1302:
1298:
1294:
1290:
1286:
1283:
1279:
1275:
1271:
1267:
1263:
1262:coastal plain
1259:
1255:
1251:
1247:
1243:
1239:
1235:
1231:
1227:
1223:
1218:
1216:
1215:precipitation
1212:
1208:
1204:
1200:
1199:coastal plain
1196:
1192:
1188:
1184:
1180:
1176:
1172:
1168:
1164:
1161:
1157:
1153:
1149:
1145:
1141:
1137:
1133:
1129:
1125:
1121:
1117:
1116:Maastrichtian
1113:
1109:
1105:
1099:
1092:
1087:
1075:
1070:
1066:
1064:
1059:
1055:
1051:
1047:
1046:
1041:
1039:
1038:Edmontosaurus
1034:
1030:
1026:
1022:
1018:
1014:
1010:
1009:
1004:
1003:caenagnathids
1000:
999:ornithomimids
997:
995:
990:
989:
988:Tyrannosaurus
984:
980:
976:
972:
968:
964:
963:
958:
954:
950:
946:
945:invertebrates
942:
938:
935:. Remains of
934:
930:
926:
922:
918:
914:
910:
906:
902:
898:
894:
890:
881:
872:
870:
866:
861:
859:
854:
852:
848:
844:
835:
826:
824:
820:
811:
807:
805:
801:
797:
793:
789:
785:
781:
777:
773:
763:
761:
757:
753:
749:
745:
741:
737:
732:
730:
726:
722:
718:
714:
710:
706:
702:
698:
694:
690:
689:Maastrichtian
686:
682:
678:
673:
671:
667:
663:
659:
655:
651:
647:
643:
639:
635:
631:
627:
619:
614:
513:
413:
403:
399:
395:
392:
389:
385:
382:
378:
374:
369:
366:
363:
359:
356:United States
355:
351:
348:
344:
340:
336:
333:
329:
324:
315:52.6°N 74.4°W
296:
294:
290:
285:
257:
255:
251:
246:
243:
239:
235:
231:
228:
224:
221:
217:
214:
210:
205:
201:
197:
194:
191:
187:
184:
181:
177:
173:
169:
166:
165:Montana Group
163:
159:
156:
153:
149:
145:
139:
134:
121:
116:
111:
106:
101:
96:
91:
86:
81:
76:
71:
66:
60:
51:
47:
43:
42:Maastrichtian
39:
35:
31:
27:
22:
19:
4306:
4296:
4290:
4275:. Retrieved
4263:
4257:
4241:. Retrieved
4239:: 9–11. 1905
4236:
4230:
4210:
4204:
4189:. Retrieved
4184:
4178:
4163:. Retrieved
4158:
4152:
4128:
4122:
4106:
4100:
4075:
4071:
4055:
4049:
4040:
4036:
4027:
4023:
3996:
3969:
3942:
3928:. Retrieved
3913:
3893:
3873:
3853:
3844:, David B.;
3817:
3811:
3785:. Retrieved
3778:the original
3773:
3767:
3758:
3753:Bakker, R.T.
3720:
3714:
3674:
3668:
3628:
3622:
3618:
3614:
3605:
3591:Paleontology
3581:
3571:
3565:
3555:
3529:
3523:
3482:
3476:
3431:
3427:
3403:. Retrieved
3383:. Retrieved
3367:. Retrieved
3362:
3339:. Retrieved
3335:
3319:Bibliography
3292:
3288:
3282:
3247:
3243:
3236:
3203:
3199:
3193:
3166:
3147:Johnson 1989
3112:
3106:
3081:
3077:
3071:
3062:
3048:
3034:
3022:
2977:
2973:
2963:
2958:Eberth, 1997
2954:
2945:
2936:
2929:DePalma 2010
2924:
2915:
2911:
2905:
2896:
2887:
2875:
2866:
2839:
2827:
2818:
2809:
2797:. Retrieved
2786:
2751:
2747:
2737:
2725:. Retrieved
2697:
2693:
2683:
2663:, Antarctica
2624:
2597:
2582:Magnoliaceae
2575:
2558:Penosphyllum
2556:
2544:
2522:
2513:
2512:
2505:
2497:
2496:
2483:
2477:Taxodioxylon
2475:
2469:Sequoiaxylon
2467:
2455:
2443:
2438:Cupressaceae
2431:
2422:
2421:
2416:Equisetaceae
2409:
2364:
2348:
2221:1 sphenopsid
2208:
2204:
2203:
2179:North Dakota
2171:South Dakota
2167:Slope County
2163:North Dakota
2156:
2145:
2139:
2136:
2104:Great Plains
2070:
2064:
2051:
2045:
2015:
1996:
1990:
1984:
1978:
1972:
1962:
1956:
1950:
1947:
1912:
1906:
1900:
1894:
1891:Kirk Johnson
1872:
1864:
1854:
1832:Great Plains
1785:
1779:
1722:
1690:
1684:
1680:Paronychodon
1678:
1674:Dakotaraptor
1672:
1668:
1664:Acheroraptor
1662:
1658:
1652:
1646:
1640:
1630:
1620:
1618:
1614:Ankylosaurus
1613:
1609:
1606:Ornithomimus
1605:
1601:
1597:
1593:
1589:
1588:
1583:
1579:
1575:
1571:
1567:
1560:
1552:
1546:
1540:
1536:Paronychodon
1534:
1528:
1522:
1515:
1511:Dakotaraptor
1509:
1505:Acheroraptor
1503:
1497:
1491:
1487:Denversaurus
1485:
1479:
1475:Ankylosaurus
1473:
1467:
1463:Ornithomimus
1461:
1455:
1453:
1448:
1444:
1440:
1436:
1432:
1428:
1427:were found.
1422:
1416:
1410:
1407:
1399:
1393:Troodontidae
1391:
1383:
1375:
1367:
1359:
1351:
1343:
1337:Ceratopsidae
1335:
1329:
1299:, ferns and
1293:South Dakota
1219:
1207:crocodylians
1177:such as the
1101:
1043:
1036:
1006:
992:
986:
960:
913:champsosaurs
886:
875:Paleobiology
862:
855:
840:
816:
796:South Dakota
792:North Dakota
769:
733:
717:crocodilians
674:
658:South Dakota
654:North Dakota
637:
625:
623:
397:Year defined
391:Barnum Brown
379:Hell Creek,
371:Type section
343:South Dakota
339:North Dakota
281:46.9; -101.5
238:conglomerate
18:
4277:17 December
4243:17 December
4213:: 823–845.
4191:17 December
4187:: 6–8. 1907
4165:17 December
4131:: 115–150.
3619:Bugenasaura
3365:. p. 1
3273:10871/30937
3149:, p. .
3066:Evans, 2013
2891:Broad, 2019
2846:, p. .
2844:LeCain 2010
2754:(11): 435.
2748:Geosciences
2727:13 November
2657:, Argentina
2608:Platanaceae
2515:Angiosperms
2462:Taxodiaceae
2457:Elatocladus
2424:Gymnosperms
2288:angiosperms
2224:10 conifers
2169:) and from
2112:fern spores
2042:plane trees
2001:, and many
1943:Cannabaceae
1866:Astrocaryum
1822:mixed with
1804:angiosperms
1800:Angiosperms
1733:angiosperms
1590:Triceratops
1580:Triceratops
1564:ontogenetic
1521:a possible
1447:, and five
1441:Triceratops
1429:Triceratops
1412:Triceratops
1230:shallow sea
1175:gymnosperms
1065:are known.
1033:hadrosaurid
1021:ankylosaurs
994:Triceratops
979:sea turtles
975:plesiosaurs
947:(including
933:salamanders
901:Vertebrates
766:Description
320:52.6; -74.4
318: /
279: /
254:Coordinates
57:68–66
4356:Categories
4299:: 774–777.
3842:Weishampel
3787:31 October
3574:: 503–510.
2813:Wilson Lab
2676:References
2604:plane tree
2599:Platanites
2524:Artocarpus
2405:cycadeoids
2336:seed cones
2319:Palm trees
2274:(uncommon)
2120:fern spore
2096:angiosperm
2058:palm trees
1971:including
1931:Urticaceae
1923:herbaceous
1840:palm trees
1725:floodplain
1686:Pectinodon
1637:Troodontid
1517:Pectinodon
1493:Torosaurus
1301:cycadeoids
1282:angiosperm
1278:understory
1266:palm trees
1254:lacustrine
1246:floodplain
1183:cycadeoids
1171:angiosperm
1163:floodplain
1124:Cretaceous
1112:sandstones
1096:See also:
983:amphibians
909:crocodiles
905:pterosaurs
865:Tanis site
758:, and the
697:Cretaceous
685:sandstones
638:Hell Creek
4310:(Thesis).
4266:(5): 87.
4219:2246/1936
3848:, Peter;
3834:130751879
3745:129985735
3699:128681314
3585:(Thesis).
3559:(Thesis).
3515:253638918
3352:0362-4331
3084:(1): 66.
2778:2076-3263
2592:Arecaceae
2570:Lauraceae
2485:Araucaria
2411:Equisetum
2062:cycadeoid
1861:Arecaceae
1828:evergreen
1824:deciduous
1777:cycadeoid
1769:paleosols
1318:Dinosaurs
1258:estuarine
1256:, swamp,
1209:suggests
1173:trees to
1156:Fort Peck
1128:Paleogene
1108:mudstones
1029:squamates
1013:theropods
1001:as well,
971:mosasaurs
949:ammonites
893:Laramidia
889:dinosaurs
869:Chicxulub
784:formation
774:and some
701:Paleogene
681:mudstones
646:formation
634:Paleocene
376:Named for
234:siltstone
230:Sandstone
216:Claystone
207:Lithology
199:Thickness
179:Underlies
171:Sub-units
4343:Archived
4325:Archived
4137:2246/387
4051:Breviora
3930:30 March
3850:OsmĂłlska
3794:Archived
3653:84273584
3507:24248432
3468:30936306
3405:22 March
3385:22 March
3014:21347420
2974:PLOS ONE
2616:See also
2577:Magnolia
2539:Rosaceae
2537:family (
2529:Moraceae
2399:various
2383:(common)
2381:Magnolia
2286:Various
2218:11 ferns
2088:conifers
1989:, while
1969:Laurales
1939:Rosaceae
1810:, 4% of
1808:conifers
1796:conifers
1792:monocots
1737:conifers
1729:woodland
1297:conifers
1242:mudstone
1179:conifers
1160:forested
1136:channels
1072:View of
962:Obamadon
957:reptiles
725:Cenozoic
387:Named by
267:101°30′W
248:Location
220:mudstone
189:Overlies
4161:: 71–72
4109:: 1–28.
4080:Bibcode
3725:Bibcode
3716:PALAIOS
3679:Bibcode
3633:Bibcode
3534:Bibcode
3487:Bibcode
3459:6486721
3436:Bibcode
3415:Geology
3369:1 April
3341:1 April
3324:General
3297:Bibcode
3252:Bibcode
3244:Geology
3228:4302433
3208:Bibcode
3086:Bibcode
3005:3036655
2982:Bibcode
2799:2 April
2756:Bibcode
2722:3515280
2702:Bibcode
2694:PALAIOS
2669:, Spain
2499:Ginkgos
2334:Redwood
2159:Dakotas
2147:Juglans
2106:at the
2100:conifer
2038:willows
2030:beeches
2018:grasses
1927:shrubby
1844:gingers
1816:prairie
1709:diorama
1654:Troodon
1574:equals
1554:Troodon
1443:, five
1250:fluvial
1211:climate
1187:ginkgos
1132:fluvial
981:), and
941:mammals
925:turtles
917:lizards
829:Geology
821:by the
800:Wyoming
788:Montana
721:iridium
705:fluvial
662:Wyoming
650:Montana
640:, near
353:Country
347:Wyoming
335:Montana
306:74°24′W
303:52°36′N
264:46°54′N
212:Primary
161:Unit of
126:↓
50:Lancian
4145:Osborn
4009:
4005:–395.
3982:
3978:–303.
3955:
3951:–204.
3921:
3900:
3881:
3860:
3846:Dodson
3832:
3743:
3697:
3651:
3513:
3505:
3466:
3456:
3350:
3226:
3200:Nature
3181:
3127:
3012:
3002:
2776:
2720:
2390:Plants
2350:Laurus
2306:leaves
2272:Ginkgo
2258:Cycads
2128:spores
2083:, and
2072:Ginkgo
2056:, and
2026:maples
1983:, and
1941:, and
1911:, and
1787:Ginkgo
1757:shrubs
1669:et al.
1659:et al.
1651:, and
1421:, and
1289:shrubs
1274:canopy
1268:, and
1140:deltas
1120:Danian
1110:, and
1054:sharks
953:plants
937:fishes
921:snakes
798:, and
782:. The
754:, the
750:, the
746:, the
693:Danian
683:, and
660:, and
644:. The
361:Extent
331:Region
46:Danian
4201:Brown
3830:S2CID
3808:(PDF)
3781:(PDF)
3764:(PDF)
3741:S2CID
3695:S2CID
3649:S2CID
3602:(PDF)
3511:S2CID
3224:S2CID
2918:(24).
2718:JSTOR
2588:Palms
2401:ferns
2244:Ferns
2141:Ficus
2036:, or
1812:ferns
1773:dicot
1761:vines
1745:ferns
1699:Flora
1285:trees
1270:ferns
1191:ferns
1144:swamp
1130:) by
1104:clays
1063:amber
1005:like
929:frogs
738:, in
703:) by
677:clays
242:amber
226:Other
4287:Cope
4279:2021
4245:2021
4193:2021
4167:2021
4058:: 1.
4043:: x.
4030:: x.
4007:ISBN
3980:ISBN
3953:ISBN
3932:2020
3919:ISBN
3898:ISBN
3879:ISBN
3858:ISBN
3789:2007
3617:and
3503:PMID
3464:PMID
3407:2019
3387:2019
3371:2019
3348:ISSN
3343:2019
3179:ISBN
3125:ISBN
3010:PMID
2801:2007
2774:ISSN
2729:2020
2535:Rose
2403:and
2098:and
2034:figs
2022:oaks
1925:and
1842:and
1826:and
1759:and
1749:moss
1747:and
1735:and
1689:and
1635:and
1612:and
1551:and
1542:Anzu
1472:and
1287:and
1260:and
1224:and
1195:moss
1193:and
1185:and
1138:and
1118:and
1058:rays
1056:and
1050:bird
1027:and
1008:Anzu
991:and
977:and
939:and
931:and
863:The
691:and
624:The
400:1907
151:Type
65:Preęž’
4268:doi
4215:hdl
4133:hdl
4107:122
4088:doi
4056:343
4041:174
4028:157
4003:394
3976:302
3949:199
3822:doi
3733:doi
3704:doi
3687:doi
3658:doi
3641:doi
3621:".
3572:361
3542:doi
3530:305
3495:doi
3483:100
3454:PMC
3444:doi
3432:116
3305:doi
3293:106
3268:hdl
3260:doi
3216:doi
3204:340
3171:doi
3117:doi
3094:doi
3000:PMC
2990:doi
2764:doi
2710:doi
2144:or
1711:at
1356:20%
1348:24%
1340:40%
1189:to
965:),
951:),
36:to
4358::
4297:17
4295:.
4264:89
4262:.
4256:.
4235:.
4229:.
4211:23
4209:.
4183:.
4177:.
4159:41
4157:.
4151:.
4129:82
4127:.
4117:;
4105:.
4086:.
4074:.
4054:.
4039:.
4026:.
3828:.
3818:26
3816:.
3810:.
3774:35
3772:.
3766:.
3739:.
3731:.
3721:23
3719:.
3693:.
3685:.
3675:54
3673:.
3647:.
3639:.
3629:29
3627:.
3604:.
3570:.
3540:.
3528:.
3509:.
3501:.
3493:.
3481:.
3462:.
3452:.
3442:.
3430:.
3426:.
3397:.
3361:.
3334:.
3303:.
3291:.
3266:.
3258:.
3248:46
3246:.
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3139:^
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3092:.
3082:99
3080:.
3008:.
2998:.
2988:.
2976:.
2972:.
2916:12
2914:.
2851:^
2772:.
2762:.
2752:10
2750:.
2746:.
2716:.
2708:.
2698:13
2696:.
2692:.
2211::
2207::
2201:.
2177:,
2154:.
2079:,
2075:,
2069:,
2050:,
2044:,
2032:,
2028:,
2024:,
2020:,
2013:.
1995:,
1977:,
1961:,
1955:,
1945:.
1937:,
1933:,
1899:,
1784:,
1743:,
1683:,
1645:,
1545:,
1539:,
1533:,
1527:,
1514:,
1508:,
1502:,
1496:,
1490:,
1484:,
1466:,
1460:,
1451:.
1415:,
1388:1%
1380:1%
1372:5%
1364:8%
1276:,
1252:,
1248:,
1217:.
1181:,
1106:,
1023:,
1019:,
1015:,
973:,
927:,
923:,
919:,
915:,
911:,
907:,
825:.
806:.
794:,
790:,
731:.
679:,
656:,
652:,
345:,
341:,
337:,
240:,
236:,
232:,
218:,
115:Pg
59:Ma
40:,
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4281:.
4270::
4247:.
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4185:7
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4082::
4076:7
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3961:.
3934:.
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3887:.
3866:.
3836:.
3824::
3791:.
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120:N
110:K
105:J
100:T
95:P
90:C
85:D
80:S
75:O
70:ęž’
54:~
52:)
48:(
44:–
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