Abstract: A succession of black sandstones and slates cropped out in the Shabaertu region, Ulanhot, Inner Mongolia was redivided and assigned to the Linxi Formation during the 1:50 000 regional geological survey in 2016-2018 according to lithology, palaeontology and sedimentary environments. The newly established Linxi Formation consists of black slates and siltstones intercalated with fine-grained sandstones characteristic of continental deposits. These strata were previously involved into the Lower Permian Suolun Formation (P₁s) in the 1:200 000 regional geological survey in 1965, and into the Middle Permian Zhesi Formation (P₂zs) in the 1:250 000 regional geological survey in 2008-2011. In this study, the upper continental fine-grained clastic rocks of the Zhesi Formation are redivided into the Upper Permian Linxi Formation. The redivision of these strata may be significant to the hydrocarbon exploration in the study area.