The Story of NACSN

The North American Commission on Stratigraphic Nomenclature, charged with the goal of promoting common standards in stratigraphic nomenclature and practice throughout North America, celebrated its 70th anniversary in December, 2016. Originally named the American Commission on Stratigraphic Nomenclature, the Commission was later expanded to include representatives from the major geological organizations in Canada and Mexico, with the goal of promoting uniformity in stratigraphic nomenclature throughout North America.

The roots of this organization go back to the 1930s, when a small group of geologists, concerned with the lack of uniformity in stratigraphic terminology and application of stratigraphic principles in different regions and professional sectors across the nation, set up a self-appointed Committee on Stratigraphic Nomenclature, and began the task of formulating guidelines that would be both useful and consistent. The resulting "Classification and Nomenclature of Rock Units," were published in the Bulletin of the Geological Society of America in 1933 (G.H. Ashley et al., vol. 44, pp. 423-459).

In 1941, R.C. Moore proposed that representatives from the Association of American State Geologists, American Association of Petroleum Geologists, Geological Society of America, U.S. Geological Survey and Geological Survey of Canada should form a permanent body to oversee standard stratigraphic practices. Following World War II, Moore revived discussion among the same groups, and In 1946, the American Commission on Stratigraphic Nomenclature became a reality with Moore as inaugural chairman and M.G. Cheney as vice-chairman. The Commission was later expanded to include representatives from other major geological organizations in Canada and Mexico, and changed its name to reflect its present pan-continental scope.

The Commission is a member society of the American Geosciences Institute.



The purposes of the Commission are to

  • develop statements of stratigraphic principles
  • recommend procedures applicable to classification and nomenclature of stratigraphic and related units
  • review problems in classifying and naming stratigraphic and related units
  • formulate expressions of judgment on these matters.



Representatives serve three years, with staggered terms.

Chairman and Vice-Chairman are elected from within the Commission membership, and each serves one year. 

Most members of the Commission are representatives of the fields of paleontology, biostratigraphy and stratigraphy. 

The present-day Commission is comprised of: