LOWER MISSISSIPPIAN CONODONT BIOSTRATIGRAPHY AND THE TOURNAISIAN-VISÉAN BOUNDARY AT ARROW CANYON, NEVADA

Analysis of the conodont biostratigraphy of the Monte Cristo Group (Lower Mississippian) of the Arrow Canyon Range in southeastern Nevada permits a correlation with the Tournaisian-Viséan boundary in Belgium. Eotaphrus burlingtonensis is restricted to the upper Tournaisian anchoralis Zone in the Belgian sequence. The species dominates samples as high as the upper Bullion Limestone and is interpreted not to range into Viséan equivalents at Arrow Canyon. The lowest occurrence of Hindeodus penescitulus, in samples of the upper Bullion above the highest E. burlingtonensis, is unknown below the Viséan in Belgium and the North American midcontinent. Therefore, the Tournaisian-Viséan boundary correlates just below the Arrowhead Formation in the interval above E. burlingtonensis and below H. penescitulus. The overlying Yellowpine Limestone has the Viséan conodonts Cavusgnathus and Taphrognathus.