excavation was still continuing Xu, also a postdoctoral fellow at the American Museum of Natural History in New York, waxes enthusiastic about what has become one of Earth's most celebrated fossil beds. Discoveries there are casting light on life during the Mesozoic, specifically 130 million to 110 million years ago—a time distinguished by the diversification of dinosaurs, mammals, birds, and flowering plants. "Liaoning opens a window on the late Mesozoic that is more complete and more in ...