Mesozoic

Plesiosaurs are large marine reptiles from the Mesozoic Era.

Paleozoic rocks make up the eastern part of the Andean Mountains in Peru, while the western range is formed of Mesozoic beds, volcanic ashes and lava of comparatively recent date.

The whole history of the earth is divided into five eras, with corresponding rock-systems. These are: 1. Archæan or Eozoic¹ era, embodied in the Laurentian system; 2. Palæozoic² era, embodied in the Palæozoic or Primary system; 3. Mesozoic³ era, recorded in the Secondary system; 4. Cenozoic,⁴ recorded in the Tertiary and Quaternary systems; and, 5. The Psychozoic era, or era of Mind, recorded in the recent system.

The Mesozoic landscape of southeastern Utah can tell us much about the past, and it's one of the most intriguing and beautiful landscapes on Earth.