The Cretaceous, or Cretaceous Period, refers to an interval of geologic time in the Mesozoic Era spanning from approximately 144 million to 66 million years ago. It was during this time period that dinosaurs developed, flourished, and became extinct, and flowering plants and modern insects first made their appearance. It is often divided into Early and Late Cretaceous Epochs. The Cretaceous was preceded by the Jurassic Period and followed by the Tertiary period.

The Cretaceous was a time of great change in the earth's landmass as continents separated and migrated on the globe's surface. At the start of the Cretaceous, South America and Africa were still connected and Antarctica was attached to Australia. North America had broken from Africa but was still attached to Western Europe. India was drifting northward toward the Eurasian continent. By the end of the Cretaceous, South America had split from Africa and moved west, and...