Mesozoic era

Dinosaurs appeared about  220,000,000 years ago and they died out about 65,000,000 years ago. The time between that is the Mesozoic era. But its hard to understand  when we say it like this. Therefore, paleontologists and geologists divided them into named periods. 

They are, 

• Triassic ( named according to the fact that the rocks of that time were identified as three separate sequences in Germany).
• Jurassic (named after the Jura mountains, on the borders of France and Switzerland, when they were first studied).
• Cretaceous( named after the Latin for chalk , the most prominent rock type formed at the time in Southern England).

These too are divided into stages. Stages are divided into zones but they are too small to be of any importance here.

Given above is a chart of Mesozoic periods and stages from the encyclopedia of dinosaurs by Dougal Dixon.