The (Upper) Late Pennsylvanian Wescogame Formation is a slope-forming, sandstone, red-orange geologic unit, formed from an addition of eolian sand,[2] added to marine transgression deposits (siltstones, etc.

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 Supai Group members were created from marine (oceanic) sequences of marine transgression, and regression, thus the alternating sandstone, siltstones, 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.)

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 approximate coeval Supai and Hermosa Groups, Arizona, Utah, and northwest Colorado:[4] Because marine transgressions cover distances, over time, the coeval units are separated by distance, and type of deposition material; the local subsidence, or uplift, as well as glaciation, and sea level changes, can cause variations in the deposition sequences of transgression-regressions.