Bayshin Tsav

Geological and paleontological studies of this fossil site were conducted in the 1970s by a joint Mongolian-Russian expedition, classifying it under the Bayanshiree Formation (Shuvalov and Chkhikvadze, 1975). Elevation above sea level: 905 meters. Coverage area: 1.8 x 2.1 km. This site consists of numerous small gullies that form cliffs and minor outcrops in a vast, flat plain. It is renowned for its abundance of dinosaur fossils. The site is divided into five subsections (BTs-I, II, III, IV, and V). Bayshin Tsav-I extends from east to west, forming a southern-facing escarpment running west to east. Bayshin Tsav II and V are outcrops extending southward from the eastern end of Bayshin Tsav-I. Bayshin Tsav III and IV are lower escarpments and isolated small outcrops located southwest of the above-mentioned sections. These strata are rich in vertebrate fossil remains. Recent excavations have uncovered numerous complete skeletons, fossil clusters, and isolated bones of hadrosauroids (Ornithopoda, Dinosauria). Additionally, fossils of dromaeosaurids, ornithomimids, and therizinosaurs have been found here. The western part of Bayshin Tsav-I is notable for the discovery of dinosaur eggshells (Elongatoolithid type). The site is listed as an immovable historical and cultural heritage under state protection, officially designated by Mongolian Government Resolutions dated May 14, 2008 (No. 175) and January 8, 2020 (No. 13). Located in the territory of Khanbogd soum, Umnugovi Province, Bayshin Tsav is dated to the Late Cretaceous, specifically the Bayanshiree age (K2bs).