Dinosaur Mountain - Triassic Arizona
The base of the mountain represents the animals and plants of the Chinle
Formation, which was laid down about 225 million years ago, during the late
Triassic of Arizona. These rocks today comprise the colorful Painted Desert
and Petrified Forest of Arizona.
This meat-eating dinosaur is perhaps the best known from the Chinle
Formation. At this time, dinosaurs were relatively small and by no means the
largest animals in the fauna. Living at the dawn of the age of dinosaurs,
Coelophysis was typical for its small size. The skeleton of
Coelophysis suggests a swift creature with good eyesight with hands well
adapted to seizing and tearing prey. Members of Coelophysis may have
Little is known of this bizarre reptile. Juveniles had three-pronged
teeth and adults one-pronged-teeth, which may indicate a change of diet from
youth to maturity, perhaps from insects to fish. The neck grew faster than
the body, but in spite of its length, the neck was not greatly flexible and
its true function is unknown.