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Analysis of the distribution of coral taxa, principally genera and subgenera, in the Mississippian of the Western Interior Province of Canada and the conterminous United States permits recognition of a system of coral zones and subzones useful for correlating stratigraphic units throughout an area extending from the southwestern District of Mackenzie in the Northwest Territories of Canada to southern California in the United States. The zonation comprises six Oppel zones, four of which are divided into locally useful subzones. Coral Zone I corresponds approximately to the Kinderhookian Provincial Series and is divided into Subzones A, B, and C. Coral Zone II corresponds approximately to the Osagean Provincial Series and is divided into Subzones A and B. The Tournaisian Stage of western Europe is represented by Coral Zones I and II. Coral Zone III corresponds approximately to the lower and middle parts of the Meramecian Provincial Series and is divided into Subzones A, B, C, and D. Coral Zone IV corresponds approximately to the upper part of the Meramecian and is not divided. Coral Zone V corresponds approximately to the lower and middle parts of the Chesterian Provincial Series and is divided into Subzones A and B. Coral Zone VI corresponds approximately to the upper part of the Chesterian and is not divided. The Visean Stage of western Europe is represented by Coral Zones III and IV and Subzone VA. The lower part of the Namurian Stage of western Europe is represented by Coral Subzone VB and Zone VI. Deep-water and shallow-water coral biofacies are discussed and integrated into the zonation system. The coral zones are correlated with foraminifer and conodont zones, which provide the primary bases for establishing ranges of coral taxa. Forty-five coral genera and subgenera used in the zonation are diagnosed, discussed, and illustrated. Correlations of Mississippian formations in the Western United States and Western Canada are presented as examples of the utility of the coral zonation.

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PLATE 1. Columnar sections showing Madison Limestone-Amsden Formation contact relations in central and western Wyoming and south-cenrtral Montana.

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