Cretaceous Period (Cretaceous Period)

the last era of the Middle Generation. It is now between 135 million and 65 million years old and lasts about 60 million years. It is named because the formation is rich in chalk. Chalk is a type of limestone, mainly composed of square stone, the particles are uniform and small, can be crushed by hand. The term Cretaceous was created in 1822 by the French geologist Jean Baptiste Julien d'Omalius d'Halloy. The formation of the cretaceous period is called the Cretaceous system. The representative symbol is "K". During the Cretaceous period, the ancient continents of the south continued to disintegreate, the ancient continents of the north continued to rise, the climate begred and seasonal changes were obvious. At the beginning of this period, the bee plant appeared, and then gradually developed. Chrysanthemum and dinosaurs, pterfish, dragons, snake-necked dragons and so on from the prosperity gradually tend to extinction, mammals and birds become a new group of animals.