Although there is no clear answer to this question, paleontologists know that a revolution in life occurred during this time period. This took place as many types of modern flora and fauna made their first appearances. Some scientists theorize that it was the development, and eventual dominance, of a new group of plants, the
By the Cretaceous period, continental drift had moved the continents to nearly familiar positions: 1) North America, 2) Eurasia, 3) South America, 4) Africa, 5) the Indian subcontinent, 6) Antarctica, and 7) Australia (map based on a U.S. Geological Survey illustration).