Willow Creek Anticline (WCA) (Cretaceous of the United States)

Also known as Maiasaura type, MOR TM-160

Where: Teton County, Montana (47.8° N, 112.3° W: paleocoordinates 55.3° N, 78.0° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Two Medicine Formation (Montana Group), Campanian (83.6 - 72.1 Ma)

• 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.

• group of beds-level stratigraphic resolution

Environment/lithology: "floodplain"; paleosol/pedogenic, intraclastic, green mudstone

• facies located on Willow Creek anticline, described as "upland" facies; semiarid; layer resulted from a flooding event with "sediment gravity flows of uncertain genesis"
• fine-grained, green mudstone; calcareous rhizoconcretions, oxidized sediments - mixed with intraformational micritic cobbles and boulders

Size class: macrofossils

Preservation: coprolite

Collected by Brandvold, Trexler, Horner in 1978–

Collection methods: quarrying, surface (float), surface (in situ), mechanical,

• eggshell also present

Primary reference: 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]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 26775: authorized by Matthew Carrano, entered by Matthew Carrano on 31.10.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Paracopridae indet.1
beetle burrows in coprolites
Coniferophyta indet.1
wood in coprolites
Gastropoda
  -
Gastropoda indet. Cuvier 1795 snail
Reptilia
 Ornithischia - Hadrosauridae
Maiasaura peeblesorum n. gen. n. sp.
Maiasaura peeblesorum n. gen. n. sp. Horner and Makela 1979 hadrosaurine
PU 22405
 Ornithischia - Hypsilophodontidae
Hypsilophodontidae indet.3 hypsilophodontid
 Theropoda - Tyrannosauridae
Tyrannosauridae indet.2 Osborn 1906 tyrannosaurid
premaxillary teeth, YPM VPPU 023387, 023469, and 023475; lateral teeth YPM VPPU 023467, 023468, 023470, 024953 (three teeth); YPM VPPU 023466, lateral tooth
 Pterosauria -
 Loricata -
Crocodylia indet.3 crocodilian
 Testudinata -
Testudinata indet.3 Oppel 1811 turtle
 Squamata -