Petrographic and chemical analyses were perfomed on eight rock samples from the Cabo Corrientes Peninsula. Based on these analses the existence of an oceanic basaltic association which is represented by basalts, spilitic basalts, spilites and komatiitic basalts was stablished; these rocks suffered an intens sodic metasomatism clearly shown in the chemical analyses and in the mineralogical assemblage. It is not clear if these metasomatism has been produced by deep ocean hydrothermal metamorfism as sugested by the presence of albitization and zeolites. It is concluded that the basaltic rocks of the Peninsula on both sides of the Utria fault and specially the ones to the west of it, is tectonically uplifted oceanic crust. A similar origin can be assumed for the rocks of other peninsulas which, like the Cabo Corrientes, are western apophyses of the Baudo Sarrania (i.e.) the peninsulas located North and South of Bahias Cupica and Solano. There is a great similarity with therocks of Gorgona Island.