The Cretaceous Period

The Cretaceous Period lasted from about 145 to 66 million years ago. It was the last period when dinosaurs roamed the Earth. T. Rex, Triceratops, and many other famous dinosaurs lived during this time. It ended with the famous asteroid impact.

The Last Dinosaurs

The Cretaceous was the longest period of the Mesozoic Era. It lasted about 79 million years. Many famous dinosaurs lived during this time, including T. Rex, Triceratops, and Velociraptor. Flowering plants appeared and spread everywhere. Bees and butterflies evolved to pollinate these new flowers.

The End of an Era

The Cretaceous ended with one of the most dramatic events in Earth's history. A giant asteroid, about 6 miles wide, slammed into what is now Mexico. The impact caused fires, tsunamis, and blocked out the sun. About 75 percent of all species went extinct, including all non-bird dinosaurs.

Fun Facts

• Flowers first became common during the Cretaceous Period.
• The Cretaceous gets its name from the Latin word for "chalk" because of chalk deposits from that time.
• Sea levels were so high that much of North America was covered by a shallow sea.

Did You Know?

During the Cretaceous Period, a shallow sea called the Western Interior Seaway split North America in half from the Gulf of Mexico to the Arctic Ocean. T. Rex lived on the western shore!