Mollusks from the late Campanian upper DeGrey Formation of the Pierre Shale Group, Missouri River Valley, central South Dakota
-
Published:January 01, 2007
-
CiteCitation
James E. Fox, 2007. "Mollusks from the late Campanian upper DeGrey Formation of the Pierre Shale Group, Missouri River Valley, central South Dakota", The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas, James E. Martin, David C. Parris
Download citation file:
- Share
-
Tools
The Missouri River and its tributaries in central South Dakota have eroded into the Pierre Shale, exposing a vertical sequence of late Campanian strata, from older to younger: the Crow Creek Member of the DeGrey Formation, upper DeGrey Formation, and Verendrye Formation, deposited during the transgressive phase of the Bearpaw cyclothem.
The DeGrey Formation (Baculites compressus Ammonite Range Zone) is predominantly gray bentonitic shale with interbeds of thin and relatively pure cream-colored bentonite and bioturbated, fossiliferous black manganese-iron carbonate concretions. Fossils are molds, casts, and fragmented shell material from a diverse epifauna of marine bivalve mollusks dominated by byssate,...
Figures & Tables
Contents
The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas

GeoRef
- assemblages
- biostratigraphy
- biozones
- Bivalvia
- Brule County South Dakota
- Buffalo County South Dakota
- Campanian
- Cephalopoda
- Cretaceous
- Gastropoda
- Invertebrata
- lithostratigraphy
- Lyman County South Dakota
- Mesozoic
- Missouri River valley
- Mollusca
- morphology
- Pierre Shale
- Senonian
- shells
- South Dakota
- United States
- upper Campanian
- Upper Cretaceous
- DeGrey Member