A striking feature of the mountain belt around the Bighorn Basin is the reversal of the direction of overthrusting and the asymmetry of folding in transverse segments of the ranges. Not only do these segments of alternating southwest and northeast thrusting characterize the ranges, but the asymmetry of each continues in minor anticlines well into or completely across the adjoining basins. Five such transverse strips are described. Deformation was that of the Laramide foreland in which the pre-Cambrian rocks and structures, relatively thinly covered, were a more important determining factor than in the geosynclinal folding farther west. The greatest crustal shortening was northeast-southwest. In the basement complex there were two types of yielding: (1) horizontal shearing along two sets of near-vertical fractures, each at about 45° to the shortening, breaking the foreland in places into blocklike units; and (2) vertical movements giving ranges and basins with various individual departures from the general Rocky Mountain alignment. In the adjustment to space requirements under horizontal compression, transverse strips of the ranges and basins moved differently. The minor folds have a regional northwest-southeast trend more or less regardless of the trends of the main ranges and basins which were outlined earlier. This minor folding was relatively shallow; near the surface easiest relief was upward, and the folds were aligned normal to the greatest shortening. Although the basement deformation did not greatly influence the trend of these lesser folds, it did determine the direction of their asymmetry.