The Cretaceous period is the ninth and longest period in the Phanerozoic eon, lasting 80 million years from 145 to 65 million years ago (mya). It followed the Jurassic period, and is the third and last period of the Mesozoic era. After it came the Cainozoic era. The Cretaceous period has just two very long epochs:
The Lower Cretaceous at ~45 million years, is the longest epoch in the Phanerozoic eon.