Two major orogenic periods are distinguished in the Tertiary evolution of Calabria and Sicily in southern Italy. In the Oligo-Miocene phase the Sicilian promontory of north Africa moved toward the Apennines, causing formation of thrust wedges and ejection of plastic material This phase was followed by a series of readjustments accompanied by active sedimentation in the basins. In Pliocene-Quaternary time, deformation in the sedimentary mantle shaped the Calabro-Sicilian arc, whose various sections were subjected to differential dislocation.