SummaryPhysical analyses of 15 Orthic Podzols of south‐eastern Quebec, Canada, showed that the extent of the breakdown of the gravel, sand, and silt and the accumulation of clay was dependent on the porosity of the parent material and the type of rocks in the gravel. There was no clay accumulation in the B horizon when the results were expressed on a percentage weight per unit volume basis. The sand was fractionated into five grades. The specific gravity of the gravel was smaller than that of any sand fraction and that of the sand increased towards the finer fractions. The specific gravity of the gravel also increased down the profile; that of the sand did not. These changes were also related to the type of parent material.A value for each horizon, calculated as follows:was used as an index of weathering to show the degree of weathering intensit