Evanston Formation
Geology
Members: unnamed (10), Hams Fork Conglomerate (1)
Lithologies: "siliciclastic" (3), mudstone (1), "shale" (1), coal (5)
Paleoenvironments: terrestrial indet. (3), fluvial indet. (8)
Age range: base of the Late/Upper Maastrichtian to the top of the Tiffanian or 70.60000 to 56.80000 Ma