Conodont biostratigraphy of the Baoerhantu section in Darhan Mumingan Joint Banner, Inner Mongolia

Silurian and Devonian carbonate strata are widely distributed in the Bateaobao area, Darhan Mumingan Joint Banner, Inner Mongolia. Previouse studies are mainly fucused on corals, brachiopods, stromatoporoides and other benthic faunas. Many problems about the ages of Silurian and Devonian rocks and their correlations still remain to be solved. by the leading fossil groups such as conodonts. The conodont study clearly shows that the upper part of the Baorhantu section should be early Early Devonian, assignable to the Alugong Formation rather than the Xibiehe Formation. We have not found the records of the Wenlock and early Ludlow marine deposits and fossils in Bateaobao area. Silurian transgression in this area started during early Ludfordian. One conodont new species, Ozarkodina uncrispa sp. nov., is described in this paper.