Bear Springs, Comanche National Grassland (Cretaceous of the United States)

Where: Colorado (37.7° N, 103.9° W: paleocoordinates 37.4° N, 66.7° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Hartland Shale Member (Greenhorn Limestone Formation), Late/Upper Cenomanian (99.6 - 93.5 Ma)

• Lower one third of the Hartland Shale Member, roughly 4m above the contact with the underlying Lincoln Limestone Member. The calcarenite contains bivalve shells of taxonomically indeterminate inoceramids and the oyster Exogyra aff. E. boveyensis Bergquis , 1944. Exogyra aff. E. boveyensis was initially reported to occur in the middle Late Cenomanian based on the fossil record in Kansas (Hattin, 1975), but Kauffman et al. (1993) depicted the occurrence of this taxon (also referred to as “Exogyra n. sp. aff. E. boveyensis”) as restricted to their Calycoceras cantiaurinum ammonite zone, which is early Late Cenomanian in age. Regardless, the fossiliferous calcarenite bed examined in our study is interpreted to be early Late Cenomanian in age (ca. 94.6 Ma).

• bed-level stratigraphic resolution

Environment/lithology: deep subtidal ramp; lithified limestone

• Periodic current events and/or depositional hiatuses during which skeletal debris was winnowed and concentrated. Whereas these brief depositional episodes might signal periods of temporary sea-level regression, they can be similarly explained as storm-winnowed debris from especially significant wave events, as evidenced by the abundance of clayey rip-up clasts.
• calcarenite

Size classes: macrofossils, mesofossils

Collected by Bruce A. Schumacher in 2006

Collection methods: chemical, acetic,

• Repository: Sternberg Museum of Natural History, Fort Hays State University (FHSM)

Primary reference: M. Nagrodski, K. Shimada, and B. A. Schumacher. 2012. Marine vertebrates from the Hartland Shale (Upper Cretaceous: Upper Cenomanian) in southeastern Colorado, USA. Cretaceous Research 37:76-88 [P. Mannion/P. Mannion/M. Clapham]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 132505: authorized by Philip Mannion, entered by Philip Mannion on 20.08.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Myalinida - Inoceramidae
Inoceramidae indet. Giebel 1852 clam
 Ostreida - Gryphaeidae
 Vertebrata -
Vertebrata indet. vertebrate
ca. 10,000 bone fragments
Gnathostomata
  -
Chondrichthyes indet. Huxley 1880 cartilaginous fish
1 vertebra
Chondrichthyes
 Hybodontiformes - Ptychodontidae
Ptychodus anonymus Williston 1900 elasmobranch
35 teeth
 Rajiformes - Rhinobatidae
Rhinobatos incertus Cappetta 1973 guitarfish
4 teeth
 Lamniformes - Odontaspididae
"Carcharias saskatchewanensis" = Microcarcharias saskatchewanensis
"Carcharias saskatchewanensis" = Microcarcharias saskatchewanensis Case et al. 1990 sand tiger shark
24 teeth
 Lamniformes - Aquilolamnidae
Cretomanta canadensis Case et al. 1990 mackerel shark
1 tooth
 Lamniformes - Cretoxyrhinidae
Cretoxyrhina mantelli Agassiz 1835 mackerel shark
4 teeth
 Lamniformes - Anacoracidae
Squalicorax curvatus Williston 1900 crow shark
20 teeth
 Lamniformes - Archaeolamnidae
Archaeolamna kopingensis Davis 1890 mackerel shark
4 teeth
Osteichthyes
 Osteichthyes -
Osteichthyes indet. Huxley 1880 bony fish
18 vertebrae
Reptilia
 Squamata - Dolichosauridae
Coniasaurus crassidens Owen 1850 squamates
18 teeth
Actinopteri
 Pycnodontiformes - Mesturidae
Micropycnodon kansasensis Hibbard and Graffham 1941
3 teeth
 Pycnodontiformes - Pycnodontidae
Palaeobalistum sp. Blainville 1818
5 teeth
 Amiiformes - Caturidae
Caturidae indet. Owen 1860 bowfin
2 teeth
 Pachycormiformes - Pachycormidae
Protosphyraena sp. Leidy 1857
6 teeth
 Teleostei -
Teleostei "sp. A" Müller 1846
8 teeth
Teleostei "sp. B" Müller 1846
17 teeth
Teleostei "sp. C" Müller 1846
11 teeth
Teleostei "sp. D" Müller 1846
2 teeth
Teleostei indet. Müller 1846
1 jaw bone
 Crossognathiformes - Pachyrhizodontidae
cf. Pachyrhizodus sp. Agassiz 1850
1 tooth
Pachyrhizodus minimus Stewart 1899
1504 teeth
Elopopsis sp.
22 teeth
 Salmoniformes - Cimolichthyidae
Cimolichthys nepaholica Cope 1872
8 teeth
 Aulopiformes - Enchodontidae
Enchodus cf. shumardi Leidy 1856
12 teeth
Enchodus cf. gladiolus Cope 1872
3489 teeth, 1 jaw bone
 Aulopiformes - Ichthyotringidae
Apateodus sp. Woodward 1901
3 teeth
 Albuliformes - Albulidae
Albulidae indet. Bleeker 1859 bonefish
1 tooth plate, 4 pieces
 Tselfatiiformes - Plethodidae
Plethodidae indet. Loomis 1900
7 teeth, 6 bones