Seven profiles, representing different locations, were used for this study on particle size distribution. In every profile studied, the weight of sand decreased with depth, whereas that of clay and silt increased. The variation in the amount of sand at different depths, however, was not equal for all size fractions. Coarse sand (> 0.147 mm) decreased with depth, but fine sand (< 0.147 mm) increased as far as the accumulation horizon of clay and silt. The total decrease in the amount of sand with depth is thus equivalent to the difference resulting from the reduction in weight of coarse sand (> 0.147 mm) plus the increase in fine sand (< 0,147 mm). The increase of fine particles such as clay, silt and fine sand with depths is attributed to mechanical migration with the gravity water.