and lower members including terrigenous clastic rocks belonging to alluvial fan and braided river sedimentation of intermittent muddy waters. The overall sedimentation across the Gaogou Formation, made up by floodplain and lacustrine conglomerates, sandstones and mudstones, indicate a dry subtropical or tropical climate during deposition. The geological horizon in which Baby Louie was found is interpreted as a flat and wide alluvial fan with subfacies-flowing microfacies. Examinations made to the δ13C levels in several eggshells from the Gaogou Formation suggest that herbivorous dinosaurs of the Gaogou Formation paleoecosystem feed mainly on C3 plants and C4 plants, which also indicates sub-humid or sub-arid climate settings. Moreover, numerous scattered amber remains of conifer origin indicate that Araucariaceae was largely present in the Northern Hemisphere of Asia during the Late Cretaceous, such as the paleoenvironments in which Beibeilong lived. The repeated presence of giant caenagnathids (such as the Bayan Shireh caenagnathid or Gigantoraptor) in fluvial-based sedimentation of geological formations suggests that these large oviraptorosaurs preferred mesic habitats (well-watered) habitats over xeric (desertic) ones. Nevertheless, geological evidence from volcanic rocks of the Xionger Mountain found at the Zhaoying Village (where outcrops of the Gaogou Formation are present) indicates that the Gaogou paleoecosystem underwent hostile climate changes, characterized by a drying tendency. Changes in the humidity and precipitation levels negatively altered the paleoflora as well as both river and flood plain paleoenvironments, forcing herbivorous organisms to migrate between the foot of the mountain and flood plains. When the precipitation levels rose, the water bodies and flood plains became repopulated. In addition, carbonate carbon/oxygen isotope analyses indicate that extended periods of climatic changes ultimately deteriorated the Gaogou Formation paleoecosystem as a whole, triggering the loss of foliage cover and by extend the extinction of the local herbivorous dinosaurs. Many of the fossilized eggs across this formation were likely unable to hatch due to the paleoenvironmental conditions. The Gaogou Formation is extremely abundant in fossilized eggs, mostly those of dinosaurs and turtles. Other remains include multiple invertebrate taxa comprising fresh water non-marine bivalves, gastropods, ostracods, and abundant insect ichnotaxa (fossilized traces left by insect activity). Additional vertebrate taxa found in this unit include the sauropod Baotianmansaurus, and the nanhsiungchelyid turtle Yuchelys. Taphonomy The preservation state of Baby Louie indicates that this embryo was lying outside its parent egg when it was buried, and its orientation which is inconsistent with that of the eggs suggests that an external