at change. The rim of the basin gave way, and
the great volume of water, freed from restraint, overwhelmed the forest
with earthy material, prostrating and burying it deep beneath the flood
of sand.

In time the woody structure disappeared, and was replaced by beautifully
stained opal and agate. Again, in the lapse of time the old forest bed
was once more lifted above its former level, forming a mesa, or plateau,
of considerable extent. During subsequent ages, the elements scarred and
furrowed the plateau, forming canyons, gulches, valleys, and buttes,
thus revealing in part this ancient forest. Could these dead trees but
talk, how interesting would be their story! We can read their history
but imperfectly by examining the mutilated breast of Mother Earth, in
and on which lie these mute stone trees, dead yet made more beautiful
through their transformation.

[Illustration: _Property of the American Museum of Natural History_
The Allosaurus (carnivorous dinosaur)]

This region is called the "Petrified Forest," or "Chalcedony Park." It
is about one hundred square miles in extent, and is visited annually by
thousands of people from all parts of the world. On account of its
strange geological character it is of special interest to the scientist.

Let us make a brief trip to this wonderful stone forest. We take light
hand-baggage and board a Santa Fe train. The railway passes near the
most interesting part of the forest, and we change cars before entering
Arizona in order to take this line. The railway officials have made a
station at Adamana, six miles from the edge of the forest, in order to
accommodate the travelling public. We leave the train here and procure a
team to carry us to the forest.

Unless informed of what is to be seen one is apt to be greatly
disappointed. One's idea of a forest is usually that of a timber-covered
area in which the trees stand erect, with outspreading branches; but we
look in vain for a standing tree, or even a stump that is erect.

All are branchless trunks, prostrate on the ground, many wholly or
partly buried; moreover, they are lying in all sorts of positions, some
entire and others broken into sections; some are massed closely
together; others lie apart; and millions of pieces of all sizes are
scattered around. At places we can travel a long distance by stepping
from one log to another.

But what is that pile of variegated disk-like objects looking like the
primitive Mexican ox-