Abstract: A large number of Apus fossils were discovered in Upper Karamay Formation and Baijiantan Formation (outcrop) in Kararnay area. Xinjiang in 1964. According to symbiotic fish fossil, insect fossil and plant fossil, they were separately nominated Kararnay (Late Middle Triassic) and Baijiantan (F.arly Late Triassic) Apus fossil assem­blages. These fossil assemblages were discovered in successions in south πiargin of Junttgar Basin, Tarim Basin, Tur pan Basin and Ordos Basin, and offered a new clue to correlation and classification of the Triassic. Inferred from sedimen­tary lithofacies characteristics. the Apus could be a type of hydrobios in fresh water-brackish water living in clean, transparent, warm and still shallow water area enriched with organic matters, which can be used as facies f咽sils of shallow lake.water-filled swamp.oxbow lake and river-delta environments.

Key words: Triassic, Kararnay Formation, Baijiantan Formation, Apus fossil, Facies fossil