The 1948 discovery of oil in Cuyama Valley has focused attention on the geology of this region. The development of stratigraphic data has necessitated the use of a number of new and redefined rock-stratigraphic terms. Therefore, the following names are submitted with the belief that their consistent usage will facilitate progressive geologic discussions and interpretations: Pattiway formation, Eocene (?); Simmler formation, continental Oligocene (?); Soda Lake sandstone, Soda Lake shale, and Painted Rock sandstone members of the lower Miocene Vaqueros formation; Saltos shale and the redefined Whiterock Bluff shale members of the lower and middle Miocene Monterey formation; Branch Canyon formation, middle Miocene; Caliente formation, continental lower and middle Miocene; Q atal formation, continental upper Miocene; and the redefined Morales formation, continental Pliocene (?).

Other unnamed Eocene and Cretaceous strata occur in the area, but the assignment of rock unit names would be premature here. Igneous and metamorphic rocks consist of pre-Upper Cretaceous granitic and gneissic types and middle Miocene basaltic flows and sills. Most of the outcropping rock units have also been encountered in drill holes, and several of them are now proved as oil reservoirs.