The East Texas Field has two outstanding features: its tremendous size and the simplicity of its geologic trap. The trap occurs where the truncated edge of the productive Woodbine sand crosses regional nosing on the west flank of the Sabine Uplift. Although this discussion is based principally on a single 75 mi (120.7 km) long east-west dip electric-log cross section, conclusions were derived from studies that made use of several regional cross sections and maps. These studies indicate that a major rise of the Sabine Uplift occurred after Buda deposition and before Woodbine deposition. A later major rise occurred during upper Woodbine and Eagle Ford deposition and the resulting erosion removed all Woodbine strata from the higher reaches of the Sabine Uplift.--Modified journal abstract.