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Egg size is constricted by upper limits to the thickness of shells, researchers say

File photo shows dinosaur eggs on display at a natural science museum in China. Researchers have said that egg size is constricted by upper limits to the thickness of shells, which have to allow oxygen through to the embryo

Dinosaur eggs found in Russia

The find was uncovered when a construction crew was blasting through a hillside to build a road near the region's border with former Soviet Georgia in the Caucasus Mountains. Geologists in Russia's volatile Chechnya region have discovered what they believe to be fossilised dinosaur eggs laid by one of the huge extinct reptiles that roamed the Earth more than 60 million years ago. Picture taken April 14, 2012. (Reuters)