W. C. Gussow's hypothesis that "saturation or bubble-point pressures, if sued with discretion and understanding, are one of the most accurate methods of dating the geologic time of final accumulation in a specific reservoir" needs to be considered in light of at least 10 assumptions: (1) that very little free gas is in the trap at the time of accumulation, (2) that no gas is lost from the saturated or unsaturated oil at any time after accumulation, (3) that no gas is gained by the oil and that no gas enters the trap after accumulation, (4) that no appreciable change in chemical or physical properties of the oil takes place through time or through changes in pressure and temperature in the reservoir after accumulation, (5) that the attitudes of the overlying rocks are dete minable for the time of accumulation, (6) that there is not a loss in rock record of the surface at the time of accumulation by later erosion which removes rock units below that surface, (7) that the accumulation of the oil takes place at the saturation pressure of the migrating and accumulating oil, (8) that the temperature at the time of accumulation is the same as the present reservoir temperature and need not be taken into consideration in the calculation, (9) that the potentiometric surface was near the land surface at the time of accumulation, and (10) that hydrostatic pressure was the only significant pressure acting on the oil in the reservoir at the time of accumulation.

The degree of reliability of this method is concluded to be low.