Although frequently mentioned in geologic literature, the Bonfim Basin, commonly referred to simply as the "Caçapava Lignite", has been virtuaily unknown, until recently, from a geologic point of view. Among the interesting aspects still obscure are its age and origin. The present paper attempts to fill some of the existing gaps in knowledge as a result of the qualitative and quantitative palynological analysis of three representative samples of the lithologies in the basin. Fifty-seven species of palynomorphs and one scolecodont were identified. The palynological associations establish an Eocene age for the strata and indicate deposition under fresh-water conditions. This age, although not permitting definitive conclusions as to the origin of the basin, invalidates the correlation usually made with sediments of the upper part of the Tremembé Formation of the neighboring Taubaté Basin
