The need for cooperation between and integration of geology and geophysics in the search for petroleum is illustrated by application and analysis in the Kilgore Area, Gregg and Rusk Counties, Texas. Independent interpretations of geologic structure from regional geology and reflection seismograph survey are presented and evaluated. The geologic interpretation is revealed to be based on accurate data of insufficient density and distribution to reveal even sizeable structural features. The reflection seismograph interpretation of structure reveals both small and large features which are of doubtful validity due to questionable time-depth relationships over the area. An integrated interpretation utilizing the geological data to define velocity limitations for the seismic time-depth relationship is attempted and a theoretical corrected structural interpretation is presented. The following conclusions are reached:(1) Standard methods of exploration for petroleum often produce incorrect results; the limitations of geologic and reflection seismograph methods do not overlap; therefore, it is possible to utilize the maximum interpretation of geological data as a guide to the velocity variations which affect the seismic interpretation.(2) Lack of sufficient velocity information can be a serious handicap to utilization of the reflection seismograph method; therefore, every opportunity to obtain additional velocity information should be utilized.(3) The Kilgore Area illustrates that existing seismic interpretations of structure that are in disagreement with known geologic data may often be recomputed for a correct interpretation at a small extra cost.