The discovery rate for the year 1940 in California declined. This followed and was accompanied by a decrease in geophysical work and exploratory drilling while geological employment remained approximately the same. Only one new oil field was discovered and there were a few areal and depth extensions of known fields. Several wildcat wells were completed as small producers in what, at present, appear to be noncommercial accumulations.

Drilling within fields increased California's production potential but additions to reserves has lagged behind withdrawals and lowering of estimates in fields under development. Faster drilling has accelerated the approach to a drilled-up status for California fields. An attempt is made to arrive at the cost and length of pay-out time for an average top allowable well as an indication of the optimum expectancy for operating capital put into development wells.

Methods of attack now being used on the California exploration problem are referred to briefly.