The stratigraphy and tectonics of this area are closely related to the orogeny of the Wichita Mountains. A continuation of the complex faulting, folding, and overthrusts of the Wichita Mountain front occurs in lower Pennsylvanian and pre-Pennsylvanian beds in southern Washita and Beckham Counties. No pre-Pennsylvanian beds have been penetrated farther north to determine the northern extent of the disturbance.

Early Pennsylvanian beds were predominantly marine. Granite wash was deposited in limited areas during Des Moines time. It reached its peak of deposition in Missouri, Virgil, and early Wolfcamp time. The amount and areal extent of the granite wash gradually decreased during Permian time. No wash was deposited shortly after Wellington time.

The Pennsylvanian and Permian marine beds in the north finger into the predominantly continental beds toward the south with minor variations in thickness, except along the south margin of the area where some thinning occurs.

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