Willow Creek Anticline (WCA): Campanian, Montana
collected by Brandvold, Trexler, Horner 1978–

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
unclassified
Paracopridae indet.
Chin 2007
beetle burrows in coprolites
Reptilia - Hypsilophodontidae
Hypsilophodontidae indet. Dollo 1882
Horner 1984
Reptilia - Hadrosauridae
Maiasaura peeblesorum n. gen., n. sp. Horner and Makela 1979
16 individuals
PU 22405
Reptilia - Tyrannosauridae
Tyrannosauridae indet. Osborn 1906
Dalman et al. 2018 10 specimens
premaxillary teeth, YPM VPPU 023387, 023469, and 023475; lateral teeth YPM VPPU 023467, 023468, 023470, 024953 (three teeth); YPM VPPU 023466, lateral tooth
Reptilia - Pterosauria
Pterosauria indet. Kaup 1834
Horner 1984
Reptilia - Crocodylia
Crocodylia indet. (Owen 1842)
Horner 1984
Reptilia - Lacertilia
Lacertilia indet. Owen 1842
Horner 1984
Reptilia
Testudinata indet. (Oppel 1811)
Horner 1984
Gastropoda
Gastropoda indet. Cuvier 1795
3 specimens
unclassified
Coniferophyta indet.
Chin 2007
wood in coprolites
see common names

Geography
Country:United States State/province:Montana County:Teton
Coordinates: 47.8° North, 112.3° West (view map)
Paleocoordinates:55.3° North, 78.0° West
Basis of coordinate:estimated from map
Geographic resolution:outcrop
Time
Period:Cretaceous Epoch:Late/Upper Cretaceous
Stage:Campanian 10 m.y. bin:Cretaceous 7
*Period:Late/Upper Cretaceous *Epoch:Senonian
Key time interval:Campanian
Age range of interval:83.60000 - 72.10000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Geological group:Montana Formation:Two Medicine
Stratigraphic resolution:group of beds
Stratigraphy comments: approx. 76.7 Ma

Foreman et al. 2008: 40Ar/39Ar radioisotopic age data reported for the Two Medicine Formation (Rogers et al., 1993; present study) are consistent with the unit accumulating during most of the Campanian Stage (83.5–70.6 Ma, Gradstein et al., 2004), with deposition definitively commencing prior to 80 Ma and terminating shortly after 74 Ma.
Lithology and environment
Primary lithology:paleosol/pedogenic,intraclastic,green mudstone
Includes fossils?Y
Lithology description: fine-grained, green mudstone; calcareous rhizoconcretions, oxidized sediments - mixed with intraformational micritic cobbles and boulders
Environment:"floodplain"
Glacial or sequence phase:regressive
Geology comments: facies located on Willow Creek anticline, described as "upland" facies; semiarid; layer resulted from a flooding event with "sediment gravity flows of uncertain genesis"
Taphonomy
Modes of preservation:body,coprolite
Degree of concentration:-bonebed
Size of fossils:macrofossils
Spatial orientation:life position
Preservation of anatomical detail:good
Associated major elements:many
Disassociated major elements:many
Disassociated minor elements:many
Temporal resolution:condensed
Spatial resolution:autochthonous
Collection methods and comments
Collection excludes:some genera,species names
Collection methods:selective quarrying,surface (float),surface (in situ),mechanical,field collection
Reason for describing collection:taxonomic analysis
Collectors:Brandvold, Trexler, Horner Collection dates:1978–
Collection method comments: eggshell also present
Metadata
Also known as:Maiasaura type, MOR TM-160
Database number:26775
Authorizer:M. Carrano Enterer:M. Carrano
Modifier:G. Varnham Research group:vertebrate
Created:2002-10-31 08:07:41 Last modified:2022-02-11 09:20:43
Access level:the public Released:2002-10-31 08:07:41
Creative Commons license:CC BY
Reference information

Primary reference:
7402. J. R. Horner and R. Makela. 1979. Nest of juveniles provides evidence of family structure among dinosaurs. Nature 282:296-298 [M. Carrano/M. Carrano/M. Carrano]

Secondary references:

45731 A. M. Bailleul, B. K. Hall, and J. R. Horner. 2013. Secondary cartilage revealed in a non-avian dinosaur embryo. PLoS ONE 8(2):e56937:1-5 [M. Carrano/M. Carrano]
30046ETE K. Chin. 2007. The paleobiological implications of herbivorous dinosaur coprolites from the Upper Cretaceous Two Medicine Formation: why eat wood?. Palaios 22:554-566 [M. Carrano/M. Carrano]
76550 S. G. Dalman, S. G. Lucas, and D. E. Malinzak. 2018. Tyrannosaurid teeth from the Upper Cretaceous (Campanian) Two Medicine Formation of Montana. In S. G. Lucas & R. M. Sullivan (ed.), Fossil Record 6. New Mexico Museum of Natural History and Science Bulletin 79:125-139 [M. Carrano/M. Carrano]
79704 B. Z. Foreman, R. R. Rogers, A.L. Deino, K.R. Wirth, and J.T. Thole. 2008. Geochemical characterization of bentonite beds in the Two Medicine Formation (Campanian, Montana), including a new 40Ar/39Ar age. Cretaceous Research 29:373-385 [P. Mannion/G. Varnham]
7403 J. R. Horner. 1983. Cranial osteology and morphology of the type specimen of Maiasaura peeblesorum (Ornithischia: Hadrosauridae), with discussion of its phylogenetic position. Journal of Vertebrate Paleontology 3(1):29-38 [M. Carrano/M. Carrano/M. Carrano]
56011 J. R. Horner. 1984. Three ecologically distinct vertebrate faunal communities from the Late Cretaceous Two Medicine Formation of Montana, with discussion of evolutionary pressures induced by interior seaway fluctuations. In J. D. McBane & P. B. Garrison (ed.), Northwest Montana and Adjacent Canada. Montana Geological Society, 1984 Field Conference and Symposium 299-303 [M. Carrano/M. Carrano]
4217 J. R. Horner, J. G. Schmitt, F. Jackson and R. Hanna. 2001. Bones and rocks of the Upper Cretaceous Two Medicine-Judith River clastic wedge complex, Montana. In C. L. Hill (ed), Society of Vertebrate Paleontology, 61st Annual Meeting, Bozeman. Guidebook for the Field Trips: Mesozoic and Cenozoic Paleontology in the Western Plains and Rocky Mountains, Museum of the Rockies Occasional Paper 3:3-13 [J. Alroy/J. Alroy/M. Carrano]
70703 G. C. Nadon. 1993. The association of anastomosed fluvial deposits and dinosaur tracks, eggs, and nests: implications for the interpretation of floodplain environments and a possible survivial strategy for ornithopods. Palaios 8:31-44 [M. Carrano/M. Carrano]