The (Upper) Late Pennsylvanian Wescogame Formation is a slope-forming, sandstone, red-orange geologic unit, formed from an addition of eolian sand, added to marine transgression deposits, (siltstones, etc.), and found throughout sections of the Grand Canyon, in Arizona, Southwest United States. It is one of the upper members of the Supai Group 'redbeds' (member three of four major units), with the Supai Group found in other sections of Arizona, especially in the Verde Valley region, or as a basement unit below the Mogollon Rim, just eastwards or part of the basement Supai Group of the southwest & south Colorado Plateau.