Stratigraphic Stand-Off at the 49th Parallel

The 49th Parallel divides the western Prairies between Canada and the United States, crossing the central part of the Williston basin and marking the International boundary that separates Saskatchewan from the States of Montana and North Dakota. Discoveries of oil in this area during the 1950s triggered widespread geological activity, and revealed significant differences of stratigraphical understanding on each side of the border. Problems seemed to arise from contrasts between ‘American' and ‘English' interpretations of stratigraphical method, particularly for the oil-producing zones of the Mississippian. This study analyzes the differing points of view, and presents historical reasons for them. Difficulties with stratigraphical method and nomenclature in the 1950s were quite real, becoming the subject in 1959 of a special AAPG-SEPM conference at Dallas. Had the delegates attending that meeting (including the present author) possessed a little more history, they would have known that an ‘American' or mineral-focused view of stratigraphy had originated in a German hard-rock mining terrane, principally through the teaching of Abraham Werner. From there, during the first years of the 19th century, it traveled via Scotland to the State of New York, where, from Amos Eaton's Rensselaer School at Troy, it spread to most of the newly-formed State geological surveys. Some years later, on the other hand, an ‘English' or ‘stratum-focused' view of stratified formations migrated across the Atlantic from the pastoral landscapes and gently inclined rock-formations of southern England, where mapping had tended to discount their mineral content in favor of their observable order and continuity.