Wayan Formation

Wayan Formation
Stratigraphic range: Albian-Cenomanian 100.6–97.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Eggshell of the oogenus Macroelongatoolithus on a Wayan Formation outcrop. Image used courtesy of the USFS Paleontology Program
Type	Geological formation
Underlies	Sage Junction Formation
Overlies	Smiths Formation
Thickness	1,344 m (4,409 ft) in western Tincup Canyon area, Caribou County
Lithology
Primary	Mudstone, sandstone
Other	Conglomerates, limestone & tuff
Location
Region	Idaho
Country	United States
Extent	Caribou Mountains

The Wayan Formation is a geological formation in Idaho whose strata date back to the latest Early Cretaceous and the earliest Late Cretaceous. Dinosaur, other reptile, mammal, and micro and macro-floral remains are among the fossils that have been recovered from the formation. The lack of extensive outcrops, limited geographic extent, and extreme structural deformation have limited paleontological explorations of the Wayan.