The four soil profiles studied occur on a toposequence. The less weathered soils, a Lithosol-argilite-shale substratum phase (TP-12) and a Red-Yellow Podzolic Soil Piracicaba variation (TP-13) are located on the lower part of the toposequence. Both soils are derived from the same kind of parent material, a siltstone of the Corumbataí formation. The more weathered soils, an Ortho Dark Red Latosol (TP-17) and a Latosol Roxo (TP-18) are located on the upper part of the toposequence. The parent material of the latter is igneous basic rock while the former had some contribution of igneous basic rock. According to the weathering mean data obtained, the intensity of weathering is the following: TP-12 < TP-13 < TP-17 < TP-18. There is an increase in the kaolinite content from 31.5% (TP-12) to 74.5% (TP-17) with intermediate values of 52.0% (TP-13) and 70.0% (TP-18) in the coarse clay of B horizon. Although the profile TP-18 is slightly less kaolinitic than the TP-17, it is somewhat more weathered, considering it contains 9.2% of gibbsite versus 3.7% in the TP-17. In the profiles TP-12 and TP-17, besides kaolinite, vermiculite, montmorillanite, allophane, mica but not gibbsite were found. In the profiles TP-17 and TP-18, besides kaolinite, allophane, gibbsite, mica, vermiculite but not mont-morillonite were found.