by tectonic uplift) supplied with dust from terrestrial areas Paleobiota The Xiaowa Formation encompasses several biostratigraphic zones. The Protrachyceras costulatum ammonoid zone of the upper Zhuganpo Formation continues into the first few meters of the Xiaowa Formation's lower member. However, the rest of the lower member (including the Guanling biota) belongs to the Trachyceras multituberculatum ammonoid zone. This unit has also been called the Austrotrachyceras triadicum zone, and is likely equivalent to the T. aon or T. aonoides zone of the western Tethys (Europe). The middle member of the Xiaowa Formation belongs to the Sirenites cf. senticosus ammonoid zone. Bivalves Brachiopods Cephalopods Conodonts Echinoderms Fish Reptiles References Geologic formations of China Triassic System of Asia Triassic China Carnian Stage Paleontology in Guizhou