The main argument of the article by William M. Davis “The Geographical Cycle” is that the geographical cycle, ideally, “is the sequence in the developmental changes of land-forms is, in its own way, as systematic as the sequence of changes found in the more evident development of organic forms” (485). However, “the geographical cycle may be subdivided into parts of unequal duration, each of which will be characterized by the strength and variety of relief, and the rate of change, as well as by the amount of change that has been accomplished since the initiation of the cycle” (487).
Davis begins with classifying the varied forms of lands as the functions of three variable quantities – structure, process and time. He further classifies the structure into “two great structural groups: first, the group of horizontal structures that includes plains, plateau, and their derivatives and, second, the group of disordered structures that includes mountains and their derivatives;” again, “classifies the (destructive) process into the chemical actions of water and air and the mechanical action of wind, heat, and cold;” and claims “timeas the governing factor for both”.
Time is certainly an important geographical element, for where the forces of uplift or deformation have lately (as the Earth views time) initiated a cycle of change, the destructive processes can have accomplished but little work and the land-form is “young;” where more time has elapsed, the surface will have been more thoroughly carved, and the form thus becomes ” mature ;” and where so much time has passed that the originally uplifted surface is worn down to a lowland of small relief, standing but little above sea-level, the form deserves to be called “old” (485).
This is where David claims the geographic cycle is similar to biological cycle; the larva, the pupa, and the imago of an insect; or the acorn, the full-grown oak, and the fallen old trunk, …, representing the young mountain block, the maturely carved mountain-peaks and valleys, and the old mountain peneplain, as representing the different stages in the life-history of a single geographic group (485).
In the end, he concludes saying that “as far as the forms of lands are concerned, no methods can equal the value of one in which explanation is made an essential feature along with observation” (504).