The Cretaceous World 145–65 million years ago

During the Cretaceous period, sea levels were higher than at any other time in terrestrial history, flooding the continental margins and creating vast, warm shallow seas teeming with marine life. Their skeletal remains became the signature deposits of chalk and marine limestone that characterize the Cretaceous, and from which its name (‘chalk-bearing’) derives. The period began with two great landmasses, Laurasia and Gondwanaland, separated by the Tethys Ocean. During the Cretaceous, continental drift saw these landmasses shear into the present-day continents. India was still joined to Antarctica, as was Australia to begin with, but Africa and South America were beginning to split, as were Europe and North America, while the future constituents of South and Central Asia formed a gigantic archipelago. The climate was warm and humid; dinosaurs dominated both land and sea, and the first flowering plants had appeared.