Three west-northwest-trending fault blocks in the subsurface northwest of the western part of the Arbuckle Mountains are bounded by faults related to recurrent and predominantly vertical movements along basement structures. The fault blocks were created as a by-product of renewed regional tension on older faults. The district linearity of the faults shows a remarkably uniform stress distribution. The occurrence of Simpson (Ordovician) rocks over Goddard and Woodford (Mississippian) strata encountered in numerous wells is considered the result of tectonic landslides. The main oil production at Eola is from sandstones of Simpson (Ordovician) age; production in the Southeast Hoover field is from upper Arbuckle limestone of Early Ordovician age.