The site of spectacular fossils, including many dinosaur remains, was found in Liaoning Province, northeast China, near the village of Beipiaon. The site contained the first fossilized internal organs of dinosaurs and the first fossil of a dinosaur containing the remains of a mammal it might have eaten. This site has also yielded the remains of Confuciusornis, one of the oldest beaked bird; the feathered dinosaur Sinosauropteryx prima; the oldest modern bird, Liaoningornis; a dinosaur found in a sleeping position; a Protarchaeopteryx, which is a primitive bird perhaps older than Archaeopteryx lithographica; the earliest flower, placental mammal, and marsupial; and many other species of dinosaurs, mammals, insects, and plants. There are new findings every year.

The fossils found at the site were preserved in great detail because the prolific rock layer is from a lacustrine (lake) deposit that was covered with a fine volcanic ash. Paleontologists speculate that a brief catastrophe, such as a volcanic eruption, killed and quickly buried everything in the area. Thus, even impressions of soft body parts, such as feathers and organs, were preserved.