Principles and Viewpoints in Formulating the Stratigraphic Classifications of the Pleistocene

The criticisms and views expressed in the recently circulated preliminary report of the Pleistocene committee of the American Commission on Stratigraphic Nomenclature on the present stratigraphic system of classification of the Quaternary suggest some lack of familiarity with the classic area of the Middle West. The multiple classification that the committee recommends, excellent as it may be for the older rocks, is not compatible with the nature of the glacial Pleistocene. The classification for the older rocks is the natural result of acquiring an understanding of them, just as the present classification of the glacial Pleistocene has evolved from decades of investigation. The classic area of the glacial Pleistocene comprises all of the type areas for the known glacial and interglacial stages of North America. So influential were the climates on most geologic processes, even in the depths of the ocean, that correlations with the glacial and interglacial stages of the Pleistocene are sought from all quarters. It is therefore important that the system of stratigraphic classification for the glacial Pleistocene shall be one that is naturally adapted to it rather than one that applies to marine strata. The non-glacial Pleistocene, however, may well be susceptible to the latter.