A reconnaissance seismograph survey was conducted during 1958 in the relatively unexplored north flank of the Delaware Basin in south central Lea County, N. Mex., using conventional methods. Data quality was fair. Interpretation was complicated by facies changes related to Permian reefing; sufficient control data to evaluate their effects were lacking. The seismic map showed about 450 feet of overall closure with fault along east flank; subsequent drilling checked the seismic map closely. The Lea field, discovered in 1960, covers about 2,280 acres and produces from three zones.