Lake Basin, Big Lake (PU) (Cretaceous of the United States)

Where: Stillwater County, Montana (45.8° N, 109.1° W: paleocoordinates 52.9° N, 76.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Bearpaw Shale Formation (Montana Group), Late/Upper Campanian (83.5 - 70.6 Ma)

• from "lower part of Bearpaw Shale"; originally considered "Ft. Pierre Shale"

• member-level stratigraphic resolution

Environment/lithology: marine; shale and gray limestone

• "Dark, soft shales predominate. There are occasional thin bands of sand and many brownish concretions which break into angular fragments. These sometimes contain marine fossils and sometimes a network of calcite seams...Some hard limestone concretions are crowded with these."

Size classes: macrofossils, mesofossils

Collected by E. Douglass in 1901; reposited in the YPM

Collection methods: quarrying, mechanical,

Primary reference: E. Douglass. 1902. Dinosaurs in the Fort Pierre Shales and underlying beds in Montana. Science 15(366):31-32 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 26767: authorized by Matthew Carrano, entered by Matthew Carrano on 30.10.2002, edited by Jonathan Tennant

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
  -
"Pelecypoda indet." = Bivalvia4
"Pelecypoda indet." = Bivalvia4 Linnaeus 1758 clam
Cephalopoda
 Ammonoidea -
 Ammonitida - Scaphitidae
Scaphites sp.2 Parkinson 1811 ammonite
 Ammonitida - Baculitidae
Baculites compressus2 Say 1920 ammonite
Chondrichthyes
 Lamniformes - Anacoracidae
Squalicorax pristodontus4 Agassiz 1843 crow shark
Actinopteri
 Teleostei -
Reptilia
 Ornithischia - Nodosauridae
Panoplosaurus sp.1 Lambe 1919 ornithischian
 Neornithischia - Hadrosauridae
Gryposaurus sp.5 Lambe 1914 hadrosaurine
Lambeosaurinae indet.3 Parks 1923 lambeosaurine
 Squamata - Mosasauridae
Mosasauridae indet.4 Gervais 1852 mosasaur
Pinopsida
 Pinales - Taxodiaceae
Sequoia sp.2 Endlicher 1847 coast redwood