|Dinosaur eggs! Geology's best-kept secrets are being uncovered at a rapid rate. Dinosaur nests, eggs, and the embryos inside them shed light on everything from animal growth to family life. Dinosaur eggs and nests have been found at 199 sites around the world. Most date from the Cretaceous period, 146 million to 65 million years ago.
Those egg-shaped rocks in your backyard arent likely to be dinosaur eggs, though. A quick look at the map shows that sites known to contain eggs are concentrated in only a few places around the world, with the richest deposits found in China, Mongolia, Argentina, India, and the Great Plains of North America.