The area is bounded by the shoreline, the 100-fathom line, and the Mexican and Canadian borders, but these

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boundaries are transgressed by Tertiary basins and structures. Scanty, localized data from diving and bottom sampling have been published. The area is largely a plain of Recent deposition concealing significant rocks by "overburden." Oil companies map in overburden areas by core drilling and seismograph as effectively as in alluviated areas onshore. Limits are placed on penetration of exploratory coring by the agency in control, except on lessees on their leases. Companies' activities and expenditures permit some "geology by inference."

Early development was by extension of onshore production. Laws hampered exploratory drilling in the absence of "drainage." By stretching the drainage concept, there was exploration, albeit unrewarding, of offshore folds traced up-plunge seaward, particularly in the Santa Barbara region. Belmont and West Newport Offshore were the only really new features of commercial value discovered before liberalization of State law in 1955. Subsequently, drilling has disproved two attractive structures in the Los Angeles basin but has discovered four oil and five gas fields in the band of folds and fault slices along the Santa Barbara coast. Are there other prospects in this band, in the Ventura basin Pliocene west of Rincon, or in the Miocene and Sespe west of Montalvo? Will Santa Monica Bay produ e where not crossed by shallow basement and will features in the Los Angeles basin on south to San Diego be attractive prospects? The answers to many of these questions are already locked in company files, and surely many are favorable.

North of Point Conception, geology by bottom samples and "inference" points up the following areas:

1) Santa Maria and Pismo basin extensions;
2) Tertiary basin between the Farallon granite ridge and the San Andreas;
3) San Andreas rift zone and land west-northwest of Point Arena;
4) Adjoining the basement rock area near the Klamath River;
5) Between Cape Blanco and the Olympic uplift where Pliocene and Miocene is established by samples and cores and structures by seismic surveys.

Test wells have been already drilled off northern California and others will be drilled off Oregon next summer.

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