PETRIFIED LOGS OF TRIASSIC AGE
A large majority of the fossil trees in Petrified Forest National Monument represent a pine-like species belonging to a group now extinct in the northern hemisphere. Some individuals of this type have diameters as great as ten feet and heights of more than 200 feet. Four or five other varieties of tree occur but they are less common and rather inconspicuous.
The process by which these trees were changed to stone took place a very long time after they were buried beneath sands and silts. At a time probably millions of years later, waters bearing in solution the mineral silica passed through the rocks of this region. Particle by particle wood was decayed, and almost simultaneously it was replaced by silica. The brilliant colors found in much of it are due to small quantities of iron and manganese which were introduced in a similar manner.
The wicked-looking upper jaw of a phytosaur—relative of the crocodile—has been discovered buried in one of the colorful mounds of mud out in the Petrified Forest. In nearby deposits are found still other fossils including ferns preserved in delicate detail and clamlike shells. These, together with the petrified logs of evergreen trees, make the picture very much alive and real to one whose imagination allows him to review these fascinating early pages in history.
DINOSAUR TRACKS
(WINGATE-KAYENTA; JURASSIC PERIOD)
Dinosaur means “terrible lizard.” Everyone has heard this name and attaches to it at least a vague conception of a creature of peculiar shape and tremendous size. In the dim far-away past these giant reptiles lived, developed and died in many parts of this country, but to most of us, they are only fantastic creatures in literature—not live or moving animals.
DINOSAUR TRACKS. PAINTED DESERT
The reality of the dinosaur should become apparent to those who travel through the Painted Desert region of Arizona. In that country the grey and red hills of clay, the cliffs of sand and the many brightly colored layers of hardened mud represent a part of the ancient landscape in which lived the “terrible lizards.” Furthermore, life definitely inserts itself into this picture when a person sees in the rocks the very three-toed tracks left by the dinosaur. Who can deny the story of life when he can place his fingers in the foot impressions and measure the strides of these animals—many of them—both large and small? Such is the privilege of those who visit the Painted Desert just south of Tuba City.