The chemical composition of our soils with established origins shows that the highest content of sesquioxides and the lowest of silica is found in soils derived form diabase. The soils from SERIE DE SÃO BENTO sandstones have the lowest content in sesquioxides and the highest in silica (sand). Several molecular and leaching values are presented. The soils from diabase show no differential migration or elimination from profile between aluminum and fron oxides. In some soils this fenomenon was found. The losses of silica and bases are produced in weathering of rocks ami the residual material is poor in bases for next losses In the diabase decomposition the losses decrease from Na, K, Ca to Mg. Comparing soils form i lie Amazon Valley with those of São Paulo, the most contrasting feature is normal occurence of ground-water laterite, sesquioxide sheet and pisolitics in the tonner. occurence. This difference between the tropical and sub-tropical soils permits the hypothesis that the considered sub or Latossol implies in two kinds of pedological processes. In this State the sesquioxides are set free by weathering and stay in the profile as colloidal material In the Amazon soils the liberated sesquioxides are partially removed from the profile (and deposited as ground-water-laterite or sesquioxide sheet) or seggregated as pisolitic material into the profile.