Thaynes Limestone

The Thaynes Formation is a geologic formation in Montana and Idaho, United States. It was recently elevated to group status, as the Thaynes Group.^[1]

Thaynes Formation
Stratigraphic range: Triassic
Type	Formation
Underlies	Ankareh Formation
Overlies	Woodside Formation
Lithology
Primary	Limestone
Location
Region	Montana, Idaho, Wyoming
Country	United States

Thaynes Limestone within Green River Basin stratigraphy

It preserves fossils dating back to the Triassic period, such as Ammonoidea, Actinopterygii, Actinistia, Conodonta, Gastropoda, Nautiloidea, Ichthyosauria, and others. A diverse fauna known as the Paris biota^[2] has been described from the Thaynes Formation.

See also

• Earth sciences portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Montana
• Paleontology in Montana
• Paleontology in Idaho