The study area is located in Serra dos Órgãos "steps" (Serra do Mar) that are the Bonito River Basin interstreams divides. The scarped sierras, steps, very dissected hills and carved valleys compartments, characterize the landforms.

The regional climate is the mesothermic rainy tropical one. In relation to the basin, the climatic conditions are affected by the elevation (averages upper than 900 m) and the slope position and vegetal cover as well.

Soil profiles with umbric epipedons were analysed in toposequences in the upper and middle slope, elevated valleys and valley floor formed from elluviums, colluviums and alluviums.

The upper slope soil profiles formed from elluviums present B cambic horizon characteristics. And in relation to the middle and down slope soil profiles, there are two situations. The first is about a pedogenesis developed from colluviums with B cambic and B oxic horizons characteristics being the former ones located in the upper sections of the middle slope and the last ones in down sections of it. And the second situation is about pedogenic colluviums with incipient pedogenesis. In some cases analysed for these two situations, these soil profiles are on paleosoils with umbric epipedons.

The soil profiles formed from alluviums are situated in two sections: elevated valleys and valley floor. The former ones have characteristics that correspond to Alluvial Soils and soil with B cambic horizon from fluvial terraces; the second ones have gley horizon characteristics.

The main characteristics of these umbric epipedons in soil profiles from elluviums, colluviums, and alluviums are: considerable depth (reaching 145 cm in some cases); 7.5 YR dominant hue, with values and cromas between 3 and 2; high organic carbon values (upper than 6.0 in average for soils in the slope and upper than 3.0 for soils in the valley) and organic matter content (reaching about 16.0) tending to decrease in depth; base saturation values under than 50%; and pH values under than 4.5 for the majority of the analysed horizons.

The present topographic position of these soils and most recent transported materials and their physical and chemical characterization as well are important to the explanation of the present and recent slope process action and the landform evolution in these areas.