The study area comprises a stretch of hilly landforms on the right margin of the Paraíba do Sul river, approximately between São José dos Campos and Caçapava cities, known as São José dos Campos plateau. The Paraíba do Sul river upper-middle valley is located in Taubaté basin, a 220 km long continental taphrogenic basin in the E-NE trending Serra do Mar Rifts System, filled with Tertiary and Quaternary sediments of Taubaté group. The middle and upper fluvial - lacustrian rock sequences include mudrocks and claystones interbedded with, and capped by, sandstones and pebble layers.

Multispectral MSS/LANDSAT images helped to identify topographic levels and interfluves morphology in the SW section of Taubaté basin. Level summits (630 to 700 m) located along the NW slope of Serra do Mar are the best preserved areas of a Upper Tertiary planation surface identified as Neogene by Martonne and currently known as São José dos Campos plateau. Narrower and lower (610 to 630 m) interfluves are found downstream.

Detailed landform and materials survey indicate the regional extension of depressions and slope hollows and predominance of extensive latossolic covers which can be related to geochemical activity in São José dos Campos surface. Progressive lowering of interfluves from SW to NE points to ongoing degradation of the planation surface from Caçapava towards the SW extremity of Taubaté basin. These processes are probably linked to water-table lowering to a regional base-level associated to exposures of Precambrian rocks cutting Tertiary sediments near Caçapava. Predominance of solution processes reveal that São José dos Campos plateau evolution is related to geochemical processes and etchplanation rather than to mechanical morphogenesis as previously suggested.