The Jurassic Period started 210 million years ago and ended
145 million years ago. It was was the height of the dinosaurs
existence on earth. Dinosaurs of all shapes and sizes roamed
the Earth, with lush vegetation nearly everywhere. Evergreens
were in abundance. Archaeopteryx, the first bird, appeared in
the late Jurassic Period along with a number of species of flying
reptiles called pterasaurs.
The oceans were home to many species of sharks, fishes and
aquatic reptiles. Though the arthropod trilobite had vanished
from the seas at the close of the Paleozoic, many species of
the cephlopod mollusk ammonite thrived during the Mesozoic, reaching
their peak during the Jurassic Period, for the dining pleasure
of the many carnivorous vertebrates of the sea.