differential erosion

(geology) Rapid erosion of one area of the earth's surface relative to another.

The selective erosion of surfaces, so that softer rocks, such as clays and shales, or lines of weakness, such as joints and faults, are eroded more rapidly than resistant, competent, and unjointed materials. In coastal areas, headlands tend to be made of igneous, metamorphic, or the more resistant sedimentary rocks, such as sandstone or limestone, while weaker strata form bays. Swanage Bay, Dorset, provides an excellent example. In granite uplands, areas of close jointing form basins. See also tors.