Late Carboniferous and Early Permian brachiopod faunas are described from the Xiaohaizi section of the Bachu area and the Shishichang section of the Kalpin area, the Tarim Basin, NW China. Biostratigraphic studies of brachiopods and associated microfossils indicate that the Xiaohaizi Formation is Moscovian (Late Carboniferous) and the Shishichang Formation is Kasimovian-Gzhelian (Late Carboniferous), whereas the Nanza and Kankarin Formations are Asselian to early Artinskian (Early Permian). Two new species proposed from the Nanza Formation are Kutorginella tarimensis and Phricodothyris? bachuensis.
Chen, Z., & Shi, G. R. (2002). Late Carboniferous to Early Permian brachiopod faunas from the Bachu and Kalpin areas, Tarim Basin, NW China. Alcheringa, 25, 293-326. https://doi.org/10.1080/03115510108527805