Cretaceous(?) basement rocks, the Puerto Plata Basement Complex (PPBC), consist of an association mostly of dismembered, variably sheared masses of rock interpreted as the remnants of an ophiolite suite. The PPBC is overlain by two units of apparently similar faunal age, neither of which was observed to overlie the other, and hence their age relations are unclear. One is the Paleocene-Early Eocene Imbert Formation consisting mostly of off-white crystal tuffs, vari-colored cherts, and sandy to pebbly turbiditic sedimentary rocks. The other unit consists of sedimentary serpentinite conglomerates and algal-limestone build-ups or patch reefs of the early(?) Paleogene shallow-water La Isla Formation. The Imbert Formation is believed to be older than La Isla. In the Late Eocene through Oligocene, a marine transgression and inner shelf(?) deposition is indicated by basal conglomerates and terrigenous sands and shales of the Luperon Formation. Miocene uplift, deformation, and change in sedimentation is interpreted as the onset of sinistral strike-slip motion and separation of northern Hispaniola from Cuba. Major regional uplift and erosion have occurred again since the Early Pliocene as the result of oblique convergence of Hispaniola with the easternmost tip of the Bahamas Bank by motion along the Oriente fault. -from Authors