From the Devils Gate limestone, Pilot shale, and Pinyon Peak limestone of the eastern Great Basin, the writers have obtained 54 species of 28 conodont genera. Species of the genus Palmatolepis can be used in refined Devonian correlation and classification with the standard stages based on ammonoid genera in Europe. Three distinct assemblage zones, designated A, B, and C, are classified as Upper Manticoceras, uppermost Manticoceras or Lower Cheiloceras and Upper Cheiloceras or Lower Platyclymenia, respectively.
The upper part of the Devils Gate can be correlated with the lower and middle Pilot and the upper Pinyon Peak. Zone A, present in these formations, can be correlated with zone II of the Houy formation in Texas, the Independence shale and its equivalents in Iowa and Illinois, the Olentangy shale of Ohio, and the lower part of the Perrysburg formation and its equivalents in western New York and northern Pennsylvania.
Zones B and C, present in the middle-lower and middle part of the Pilot and upper part of the Devils Gate and Pinyon Peak, can be correlated with zone III of the Texas Houy formation, the Grassy Creek shale and its equivalents in Illinois and Iowa, and other sections in the mid-continent and eastern United States including the Huron member of the Ohio shale of Ohio and Kentucky and the middle and upper part of the Perrysburg formation in New York and Pennsylvania.