In this work, the particle size, the mineralogic composition and the roundness of the Paredão Vermelho, Ribeirão Claro and Saltinho soil series, from the Piracicaba, São Paulo, Brazil, were studied in their fine sand (250 - 105 m) and very fine sand (105 - 53 m) fractions. The material that forms these soils is very well selected. The mineralogic composition shows the presence of stable minerals as tourmaline, magnetite, ilmenite, staurolite and zircon. In the very fine sand fraction occurs rutile. The roundness is high in the studied material, what must be indicating that it was present in more of one sedimentation cycle. By the other hand, it is possible to conclude that these soils are formed from Botucatu Sandstone.