Ages of the earth

A brother and sister travel back in time to several epochs in the Cenozoic Era and observe a variety of prehistoric mammals in their natural environment.

Aboard their Space-Time Shuttle, a brother and sister stop in the Permian Period to see prehistoric reptiles.

On their Space-Time Shuttle tour of the prehistoric world, a brother and sister land in the Jurassic Period where they see the largest and most ferocious land animals that have ever lived.

A brother and sister travel back in time to the late Devonian period where they observe the first amphibians.

As a brother and sister travel back in time to when the first living things were appearing on Earth, the reader learns about prehistoric life.