The geology of the Island of Barbados is interpreted as the manifestation of an early Tertiary submarine gravity slide. Recent geological and geophysical data from the sea floor of the western Atlantic indicates that the Barbados Ridge was similarly formed. It is proposed that the westward-drifting Atlantic sea floor under-thrusted and uplifted the Caribbean block, and formed the Puerto Rican trough and the associated negative gravity anomaly. In early Tertiary time, shallow-water marine and continental clastic sediments, present along the eastern border of the Caribbean block, slid downslope into an area of deep-water deposition. The Antillean volcanic arc appeared at about the same period. Continued westward drift of the sea floor uplifted the slide mass to form the ridge and island of Barbados.