Velocity solutions from 165 airgun-sonobuoy reflection/refraction stations on the continental margin of southernmost South America are presented in 10 seismic structure sections. Also included are an isopach map of Cretaceous and Tertiary sediments (seismic velocities generally less than 4.2 km/sec) in the Magellan, Malvinas, Falkland Plateau, and Falkland Trough basins, and three north-south single-channel seismic reflection traverses of the Falkland Plateau, Falkland Trough, and North Scotia Ridge. The Falkland Trough is a silver of oceanic crust between the Falkland Plateau and the North Scotia Ridge. The acoustic basement and deep sedimentary layers of the plateau extend beneath the trough and then are subducted beneath the northern flank of the ridge. Movement of the ridge and the plateau toward each other has apparently resulted in the deformation and uplift of the overlying sediments to form the northern flank of the ridge.