Kootenai Formation

Not to be confused with Kootenay Group.

The Kootenai Formation is a Lower Cretaceous geologic formation. The Kootenai was deposited in a foreland basin east of the Sevier thrust belt in western Montana. The lithology consists of a basal conglomerate with overlying non-marine sandstones, shales and lacustrine limestones.^[1]

Kootenai Formation
Stratigraphic range: Aptian-Albian
Typical Kootenai Formation in a roadcut. Sunburst Sandstone Member overlying the red informally named member 2. Cascade County, Montana.
Type	Geological formation
Sub-units	Cut Bank Sandstone Member, Moulton Member, Pryor Conglomerate Member, Sunburst Sandstone Member.
Underlies	Blackleaf Formation
Overlies	Morrison Formation unconformably
Thickness	75 to 195 metres (246 to 640 ft)
Lithology
Primary	Nonmarine mudstones, siltstones and sandstones
Location
Region	Montana, Idaho
Country	United States
Type section
Named for	Kootenai Tribe who occupied western Montana and Alberta

The most common fossils found within the Kootenai Formation are gastropod, ostracod, and pelecypod shells. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.^[2]

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with indeterminate dinosaur fossils