The influence of the Geological Society of America Bulletin on the development of quantitative geomorphology is demonstrated by three papers: Horton (1945), Mackin (1948), and Strahler (1952a), all published in the Bulletin. Horton (1945) advocated a move from qualitative to quantitative approaches in the study of landforms. He proposed quantitative tools and techniques by which we could analyze the landscapes around us. His paper not only stimulated statistical and mathematical approaches to geomorphic research and description but raised fundamental questions such as the randomness or determinism of surface processes. Mackin's (1948) paper was influential in the development of quantitative geomorphology because it prompted the work of Leopold and many others on the hydraulic geometry of river channels. In that paper, he also proposed several concepts fundamental to the dynamic geomorphology system of Strahler. Strahler's (1952a) paper set forth some guiding principles underlying quantitative methods of investigating landforms. He advocated the use of statistical techniques in landscape analyses of all geomorphic processes. In that paper, Strahler also integrated Mackin's (1948) concept of system and that of a dynamic equilibrium into a new "dynamic" geomorphology. These three papers were fundamental in the origin and growth of quantitative, process-oriented geomorphology.
Future trends lie in the fields of environmental geomorphology, global and planetary studies, and morpho-tectonics with accent on applied problems and cooperation with other disciplines.