In Arizona, that land of mystic beauties and many wonders, lies a great
tract of land that, once upon a time, was covered with waters of the
sea. How many centuries ago the ocean waves sparkled and rippled over
what is now the desert, no one can definitely say. But from the nature
of the stratum is which great logs are embedded, and the fossilized
reptiles found, it is known that they were entombed during the Triassic
age, many millions of years ago.
Petrified logs are found over a wide area, more than a hundred square
miles being covered with varying amounts of the “stone” trees. This
fossilized “forest” is greater in area, more highly colored, and
contains more petrified wood than any like deposit in the world.
Many visitors who have heard of the “forest” drive through miles of the
Reservation and ask at the Museum where they can find the Petrified
Forest. Inquiry discloses that they expected to find an area of standing
trees, trunks merely turned to stone, branches and all. Perhaps they
have seen one or more such trunks in Yellowstone National Park and think
to find hundreds of them here. Yet, when they learn the story of these
fallen monarchs, and catch a glimpse of the dazzling beauties of agate
and carnelian, jasper and onyx, no signs of disappointment are seen. Let
the visitor but leave his car to view the logs, and step by step he is
led on by here a gleaming fragment of carnelian, and there the soft
sheen of jasper and topaz. It is like the carpet of Fairyland.
These trees did not grow where they lie, or even within many miles of
where they are found. They were carried from a long distance to this
region by flood waters, and after whirling and drifting around in the
inland sea then covering the land, they became waterlogged and finally
sank to the bottom, where some eddy or whirlpool carried them. Here they
lay for countless centuries, slowly being covered by silt and sand,
while yet other logs came to rest above them. Thousands of years elapsed
during this drifting and sinking into oblivion under the ooze of this
Triassic Sea. And then came Old Ocean, later on in the Mesozoic Age
submerging the entire region and adding its weight to the terrific
pressure already brought to bear on the burial place of the giants. This
pressure packed the sands to stone, and compressed the clays to shale.
Already the logs were impregnated with a strong solution of silica, with
iron and manganese also present, and the pressure forced it into every
fiber. Atom by atom the cells of the wood were dissolved and replaced by
the silica, which hardened, taking the exact shape of the cell it
destroyed. While the logs were probably partly petrified before the
influx of the ocean waters, a great many show that enormous pressure was
brought to bear while they were yet flexible.
Some logs recently brought to light by the summer floods, are mashed
almost flat, cross sections measuring eighteen inches one way and more
than five feet the other.
[Illustration: Courtesy National Park Service