Bugiin Tsav gives the feeling of stepping into the past 150 million years ago. It is possible to discover fossils of dinosaurs weighting up to 80 tons, comprising 20m in length and up to 4m of hight. Visitors will find remnants of mussel, indicat¬ing a bed of large freshwater lake or inland sea existing 200 million years ago. The petrified remnants of the ancient giants and water animals are found not only in Bugiin Tsav but also in Shinejinst soum's Green Tsav, around Bogd soum's Orog lake, Am river and Luu Yast.