Progradation of the northern Gulf of Mexico slope differentially loaded a stretching allochthonous salt sheet at least 80 km long. Loading segmented the landward margin of the allochthon into smaller salt structures: (1) irregular, rootless salt massifs separated by ovoid intrasalt basins; (2) rootless salt stocks within a linear basin; and (3) isolated remnant salt rollers overlying a discontinuity marking the level from which the allochthon was displaced. During partitioning, salt migrated basinward to feed the leading edge of the allochthon. Most salt structures on the upper continental slope are thought to have formed by segmentation of much larger allochthonous sheets.