Parallel slope retreat in humid climate

Three different statistical tests are applied to slopes on relatively uniform lithologies in northern Alabama. The tests applied are: Student's t, the correlation coefficient r, and analysis of variance. One hundred forty‐five slope measurements were available for study. The following conclusions are drawn for the study area: (1) streams in V‐shaped valleys are flanked by convex‐upward slopes; (2) slopes above pediments, valley strips, or floodplains are lower than the slopes above actively downcutting streams; and (3) slopes above pediments, valley strips, or floodplains retreat at essentially constant angles. All three statistical tests yield the same results.