Daohugou Beds

The Daohugou Beds are a fossil-rich part of the Haifanggou Formation, also called the Jiulongshan Formation, near Daohugou village in Ningcheng County, Inner Mongolia, China, deposited in deltaic and lacustrine settings. The formation is dated to the Callovian-Oxfordian, roughly 165 to 160 million years ago in the Middle to Late Jurassic, though the age of the Daohugou Beds specifically has been debated, with proposals ranging from about 169 million years to as young as 122 million years; it consists mainly of coarse conglomerate with sandstone, mudstone, shale and thin coal layers, overlying the Beipiao Formation and underlying the Tiaojishan Formation. The beds are extraordinarily fossil-rich, with at least 760 described insect species making them one of the most diverse Jurassic insect-bearing deposits known, alongside vertebrate fossils including dinosaurs, pterosaurs, early mammals, amphibians and fish, and abundant plant remains.