Regional stratigraphy of North America / Региональная стратиграфия Северной Америки

Stratigraphy lies at the heart of geology and we have set for ourselves the rather daunting task of describing, albeit in summary fonn, the regional stratigraphy of North America. Our purpose is to develop a stratigraphic framework against which to view the history of the continent and with which to test ideas about Earth mechanics. No such treatment can ever be complete, as ours is not, but we hope the attempt will provide the reader with at least a working summary of North American stratigraphy and geological history. Through all the changes in geological understanding that have marked the history of geology, one of the primary
goals of geological science has been the elucidation of the history of our planet. To that end, generations of geologists have measured, collected, analyzed, and theorized. It is our belief in writing this book that knowledge of the Earth can only come from careful analysis of the rocks themselves, that hypotheses and theories, though vital in the ordering of bservations, must always be constrained by the data. One of the most important, and difficult, parts of dealing with stratigraphy is organization of available data in the most natural fashion. To this end, we employ in this book a system which blends the best of both time- and stratumbounded units as stratigraphic subdivisions. The remainder of this chapter describes the fonnat of all subsequent discussions <...>