The South Boling field, Wharton County, Texas, on the south flank of the Boling piercement-type salt dome, was discovered in November, 1951, by the side-tracking of Michel T. Halbouty's Gary Estate No. 1-A, a dry hole. Four dry holes including the 1-A well were drilled in the area by the operator in the attempt to discover the field. After discovery, development proved the controlling structural feature to be a thrust fault associated with the Boling piercement-type salt dome. Some wells penetrated as much as 1,000 feet of overthrust Jackson (Eocene) shale before reaching the younger Frio (Oligocene) beds below the plane of the thrust fault. Ten productive Frio sands and one productive Marginulina sand have to date been established in the field. The significance of the th ust fault to Gulf Coast geological thinking and its expected effect on future exploration of piercement-type salt domes are discussed.