ABSTRACT: The best exposures of the Menard Formation in the upper Mississippian outcrop belt around the Illinois Basin, including type sections of the formation and its named members, yielded the conodont fauna on which this study is based. Twenty-five species and twelve genera, including the new species Ozarkodina! Magnivarians, are recognized. Average abundance of conodonts is 11 specimens per kilogram of sample. The ranges of two stratigraphically important species have been extended: that of Kladognathus mehli (Rexroad) upward from the Glen Dean Limestone (Chester Series) and that of Cavusgnathus navicula (Hinde) downward from the Kinkaid Limestone (Chester Series). As a result, the stratigraphic position of the lower boundary of the Kladognathus-Cavusgnathus navicula Assemblage Zone has been shifted downward from the base of the Kinkaid Limestone to the base of the Menard Formation, and Kladognathus mehli has been excluded from the group of species defining the upper limit of the Gnathodus bilineatus-Kladognathus mehli Assemblage Zone. The Siberia Limestone of C.A. Malott, previously abandoned as a synonym of the Menard, represents only a small part of the Menard in its type area, and Malott's unit is recognized herein as the Siberia Limestone Member of the Menard Formation.

Rexroad, C. B., Nicoll, R. S. 1965, Conodonts from the Menard Formation (Chester Series) of the Illinois Basin: Indiana Geological Survey Bulletin 35, 28 p., 5 fig., 2 pl.

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Keywords: paleontology, Menard Limestone, Mississippian, conodont, Buffalo Wallow Group, fossil, Siberia Limestone Member, Tobinsport Formation

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