The boundary between the Jurassic and the Cretaceous in Brazil is not well defined. During this time, the geological history of the Brazilian continental marginal basins is related to the initial stages of the separation of the Brazilian and African plates: the continental or pre-rift (Donjoaniano stage) and the lacustrine or rift phase (Bahiano stage). The lack of marine fossils does not allow an exact correlation with the standard stratigraphic column but the study of fresh water ostracodes, polen and fishes, common to Brazil and West Africa basins, suggest lhe boundary Jurassic-Cretaceous in the upper part of the Donjoaniano stage during the deposition of the Sergi-Serraria Missão Velha sandstone.Resumo indisponível.