Shishugou Formation

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The Shishugou Formation is a Late Jurassic geological formation in Xinjiang, China. It is part of the Qigu Group and sits in the northern Junggar Basin. The lower Wucaiwan Member is now considered the lowest part of the formation. The rocks are mainly red mudstone, with layers of sandstone, conglomerate, and occasional volcanic ash, and the formation is about 380 meters thick.

The site is famous for its diverse theropod dinosaurs and several well-preserved fossil “death pits” where many skeletons were buried together in shallow, mud-filled hollows created by trampling and volcanic ash. These pits help scientists understand how large dinosaurs interacted and how smaller species lived with them. Notable discoveries include the early tyrannosauroid Guanlong, small ceratosaurs like Limusaurus inextricabilis, and many other dinosaurs, crocodilians, pterosaurs, and early mammals.

Excavations began in 1928, led by Yang Zhongjian, yielding finds such as Tienshanosaurus. From the 1960s to the 1990s, more dinosaurs, including Mamenchisaurus and Sinraptor, were discovered. Since 2000, researchers James Clark and Xu Xing have led ongoing digs, uncovering hundreds of specimens that illuminate a burst of dinosaur evolution during this time. The area was once a marshy landscape with nearby volcanic activity, and today it features dry badlands along the edge of the Gobi Desert. The name Shishugou means “stone tree valley,” a nod to petrified wood found there, and the site has even been featured as a filming location for movies like Crouching Tiger, Hidden Dragon.