Some Characteristics of Mature Soils in Michigan*

Soil profiles from a number of localities, in the Great Lakes region of the United States have been described, and theories regarding their development have been presented by several different investigators. Along with detailed descriptions, in several instances, chemical and physical analyses by separate soil horizons also have been published. Therefore this region no longer constitutes a virgin field for soil study. In this paper, the authors are presenting some analyses not hitherto published, but otherwise are merely hopeful that their article may contain some new ideas. The term mature applied to soils does not have a very precise meaning, since the term is purely relative in time signification and the standards, or criteria, for determining degrees of maturity have not been specifically defined or certainly not generally agreed upon. Profiles, differing markedly in visible aspect and in the chemical end physical nature of the separate horizons, are so numerous that when we attempt to catalog them, the vaguely defined classes, young, mature and old prove inadequate. Perhaps a classification based upon the characteristics of the profiles themselves, as opposed to one based upon origin or causes, might be more useful. The following classification of the profiles of the Michigan region is presented as an illustration of the first kind of classification.