Cretaceous Period, 145-65 million years BP. A large pair of Charonosaurus sp. hadrosaur eggs on matrix retaining evidence of the original leathery surface. 2.5 kg, 27cm (10 1/2"). Property of a North London gentleman; acquired on the UK art market before 2000. The hadrosaurs are known as the duck-billed dinosaurs, due to the similarity of their heads to those of modern ducks. In addition to the duck bill, Charonosaurus also had a large head crest. Dinosaur eggs are known from about 200 sites around the world, the majority in Asia and mostly in terrestrial (non-marine) rocks of Cretaceous Age. It may be that thick calcite eggshells evolved during the Cretaceous (145 to 66 million years ago"). Fine condition.