Chris's Bonebed (CBB) (Cretaceous of the United States)

Also known as MPM 2256

Where: McCone County, Montana (47.8° N, 106.1° W: paleocoordinates 54.4° N, 79.0° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Hell Creek Formation, Late/Upper Maastrichtian (70.6 - 66.0 Ma)

• approx 35 m below base of "Z coal", high in Hell Creek Formation

• bed-level stratigraphic resolution

Environment/lithology: crevasse splay; gray, yellow, argillaceous, sandy conglomerate

• "sheet wash"
• "The primary fossil-bearing facies, unit 3, is a heterogeneous yellowish-gray intraformational clay-pebble conglomerate...The clay pebbles are mostly autochthonous siltstone, rounded, and held in a fine- to medium-grained sandstone matrix."

Size classes: macrofossils, mesofossils

Collected by C. West in 1977–1978

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

Primary reference: C. Lupton, D. Gabriel, and R. M. West. 1980. Paleobiology and depositional setting of a Late Cretaceous vertebrate locality, Hell Creek Formation, McCone County, Montana. Contributions to Geology, University of Wyoming 18(2):117-126 [J. Alroy/J. Alroy/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 14674: authorized by John Alroy, entered by John Alroy on 15.05.2002, edited by Matthew Carrano

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Mammalia
 Procreodi - Arctocyonidae
Protungulatum gorgun
Protungulatum gorgun Van Valen 1978 condylarth
MPM 4445, 4446
 Multituberculata - Taeniolabididae
"Catopsalis joyneri" = Valenopsalis joyneri
"Catopsalis joyneri" = Valenopsalis joyneri Sloan and Van Valen 1965 multituberculate
Reptilia
 Loricata -
"Leidyosuchus sternbergi" = Borealosuchus sternbergii
"Leidyosuchus sternbergi" = Borealosuchus sternbergii Gilmore 1910 crocodilian
 Ornithischia -
Ankylosauria indet., Thescelosaurus neglectus
Thescelosaurus neglectus Gilmore 1913 ornithopod
MPM 4377
 Ornithischia - Hadrosauridae
"Anatosaurus copei" = Edmontosaurus annectens
"Anatosaurus copei" = Edmontosaurus annectens Marsh 1892 hadrosaurine
MPM 4441, 4442
 Ornithischia - Ceratopsidae
Triceratops prorsus
Triceratops prorsus Marsh 1890 ceratopsid
 Theropoda -
Theropoda indet.2
 Theropoda - Dromaeosauridae
Dromaeosauridae indet.
Dromaeosauridae indet. Colbert and Russell 1969 maniraptoran
 Theropoda - Tyrannosauridae
"Tyrannosaurus rex" = Tyrannosaurus rex, "cf. Gorgosaurus lancensis" = Tyrannosaurus rex
"Tyrannosaurus rex" = Tyrannosaurus rex Osborn 1905 tyrant lizard king
"cf. Gorgosaurus lancensis" = Tyrannosaurus rex Osborn 1905 tyrant lizard king
 Choristodera -
Champsosaurus sp.
Champsosaurus sp. Cope 1876 choristodere
 Testudinata - Baenidae
? Baenidae indet.
? Baenidae indet. Cope 1882 turtle
 Testudines - Trionychidae
Trionychidae indet.1
Trionychidae indet.1 Gray 1825 softshell turtle
 Testudines -
"Chelonia indet." = Testudines
"Chelonia indet." = Testudines Batsch 1788 turtle
Amphibia
 Salientia - Discoglossidae
Discoglossidae "sp. C"
Discoglossidae "sp. C" Günther 1859 painted frog
maxilla
Actinopteri
 Lepisosteiformes - Lepisosteidae
Lepisosteus sp.
Lepisosteus sp. Agassiz 1843 gar
 Amiiformes - Amiidae
Amia fragosa
Amia fragosa Jordan 1927 bowfin
Chondrichthyes
 Hybodontiformes - Lonchidiidae
Lonchidion selachos
Lonchidion selachos Estes 1964 elasmobranch
 Rajiformes - Rhinobatidae
Myledaphus bipartitus
Myledaphus bipartitus Cope 1876 guitarfish
unclassified
  -
Plantae indet.
Plantae indet. Haeckel 1866
carbonized logs
1Alroy 2009; 2Carrano 2025