The controversial concepts of Edward Oscar Ulrich (1857–1944) dominated American stratigraphy during the first decades of this century. His U.S.G.S. mapping experience and extensive knowledge of the paleontology and stratigraphy of North America culminated in his masterwork: Revision of the Paleozoic Systems (1911) and several late papers (1916, 1920, 1924). The revision, which served as a guide to a generation of geologists, also contains Ulrich’s philosophy of correlation.
Application of his geological concepts to American stratigraphie successions led Ulrich to propose radical changes in existing classifications and correlations. Among his more controversial proposals were the creation of two new lower Paleozoic time stratigraphie units of systemic rank, the Ozarkian and the Canadian; a theory of oscillating troughs and barriers to explain the occurrence of the shelly carbonate and graptolitic shale facies in adjacent strike belts in the Appalachians; and the revision of the Croixan Series of the Upper Mississippi Valley. Each of these proposals was incorporated in various textbooks and correlation charts of the period.
However, as detailed stratigraphie studies in the Ozarks, the Upper Mississippi Valley, and in the Appalachians were completed, it was found that Ulrich’s concept of correlation was untenable and it was gradually replaced by one stressing facies relations. But, because of his authority, his disputative nature, and the tenacity with which he held his views, the development of American stratigraphy had been hampered.
Figures & Tables
Geologists and Ideas
An unusually coherent, well-written volume. Prepared for DNAG by the History of Geology Division of GSA. Spotlights events, ideas, and people, and sheds light on the history of North American geology as a whole. With its many intellectual jewels on the evolution of scientific concepts, this book will provide many happy hours of entertainment and instruction for anyone interested in the history of science, especially that of the earth sciences. Thirty-four papers are organized into four categories: (1) The Evolution of Significant Ideas; (2) Contributions of Individuals; (3) Contributions of Organized Groups; and (4) Application of Significant Ideas. Excellent as a course-book or for additional reading for classes related to the history of geology or general science.