The Jurassic was a geologic period that lasted from about 213 million years ago to about 144 million years ago. This was a golden age when the dinosaurs rule the land. Many of the dinosaurs grew to an enormous size. The first true bird, Archaeopteryx, evolved and many kinds of crocodile developed. During this period, vegetation was greener and more lust. Conifers were common in the Jurassic Period.