Dinosaur egg fossil sampled for geochronology, Qinglongshan, Yunyang Basin, China. Credit: Dr Bi ZhaoA new dating method has been used by researchers to determine the age of fossilised dinosaur eggs embedded in rock at Qinglongshan in central China’s Yunyang Basin. “We show that these dinosaur eggs were deposited roughly 85 million years ago in the Late Cretaceous period,” says Dr Bi Zhao, a researcher at the Hubei Institute of Geosciences, China. Interior of Qinglongshan Dinosaur Egg Fossil Museum, China. Credit: Dr Bi ZhaoIt is the first reliably dated fossilised egg from Qinglongshan, where more than 3,000 semi-exposed, 3-dimensionally intact dinosaur eggs are spread across 3 sites.