Wescogame Formation

Wescogame Formation Stratigraphic range: Upper Pennsylvanian, 312–300 Ma PreЄ Є O S D C P T J K Pg N
representative Supai Group 'redbeds' (ridgeline extending north from South Rim, Grand Canyon)
Type	Geologic unit
Unit of	Supai Group
Underlies	Esplanade Sandstone, (4th member)-Supai Group
Overlies	Manakacha Formation, (2nd member)-Supai Group-312 Ma
Thickness	200 feet (61 m) max (100-200 ft typical)
Lithology
Primary	sandstone, siltstone
Location
Region	Colorado Plateau, southwest and south
Extent	Grand Canyon, Verde Valley, and basement rocks of Mogollon Rim and central & east-northeast Arizona

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.

Coeval units of Wescogame Formation and the Supai Group are replaced by geologic units formed from geology deposited in relationship to the former basin to the south-southeast in Arizona, the Pedregosa Basin, of the Pedregosa Sea, which extended northeast to the Verde Valley region, and the earlier deposition of the red rock sandstone of the Schnebly Hill Formation, of the Sedona, Arizona region, (Oak Creek Canyon, Sycamore Canyon, and other related sub-regions).

The Late Pennsylvanian-Early Permian geologic sequence of the Supai Group common in the Grand Canyon: The Pennsylvanian is the Late Carboniferous.

The Supai Group members were created from marine (oceanic) sequences of marine transgression, and regression, thus the alternating sandstone, siltsones, conglomerate subsections (facies); the subsections are not always a continuous transition into the above section, mostly due to ocean levels, falling, or rising, glaciation, or regional subsidence-(basins, etc.) or uplift of land. Today's Wasatch Front is the approximate lineage, NNE to SSW of the western coast region of North America from where the oceans transgressed. The ancient Antler Mountains-(Antler orogeny, off-shore volcanic island arch(es)), of ancient Nevada supplied material, from the west, off the 'ancestral' West Coast. The continent supplied material from the east, both directions supplying the offshore basin, the Cordilleran Basin which became part of the Basin and Range Province, in later epochs. Three other basins were involved in this history: southwest of the Ancestral Rocky Mountains was the Paradox Basin-(eastern Utah to Southwest Colorado), northeast was the Central Colorado Basin-(NW Colorado, NE Utah, SW Wyoming); the Oquirrh Basin was north-northwest, at present day northwest Utah.