The fossil forest that was first brought to scientific attention is on
the northern slope of Amethyst Mountain, opposite the mouth of Soda
Butte Creek, 12 miles southeast of Camp Roosevelt. The following
account, by Dr. William H. Holmes, the discoverer of these fossil
forests, shows the impression first made by them:
As we ride up the trail that meanders the smooth river bottom [Lamar
River] we have but to turn our attention to the cliffs on the right
hand to discover a multitude of the bleached trunks of the ancient
forests. In the steeper middle portion of the mountain face, rows of
upright trunks stand out on the ledges like the columns of a ruined
temple. On the more gentle slopes farther down, but where it is still
too steep to support vegetation, save a few pines, the petrified
trunks fairly cover the surface, and were at first supposed by us to
be shattered remains of a recent forest.[2]
These trunks may easily be seen from the road along the Lamar River,
about a mile away. They stand upright—as Holmes has said, like the
pillars of some ruined temple—and a closer view shows that there is a
succession of these forests, one above another. In the foothills and
several hundred feet above the valley there is a perpendicular wall of
volcanic breccia, which in some places attains a height of nearly 100
feet. The fossil trunks may be seen in this wall in many places, all of
them standing upright, in the position in which they grew. Some of these
trunks, which are 2 to 4 feet in diameter and 20 to 40 feet high, are so
far weathered out of the rock as to appear just ready to fall: others
are only slightly exposed: niches mark the places from which others have
already fallen: and the foot of the cliff is piled high with fragments
of various sizes.
Above this cliff fossil trunks appear in great numbers and in regular
succession. As they are all perfectly silicified, they are more
resistant than the surrounding matrix and consequently stand above it.
Most of them are only a few inches above the surface, but occasionally
one rises as high as 5 or 6 feet. The largest trunk observed in the park
is found in this locality. It is a little over 10 feet in diameter, a
measurement that includes a part of the bark. It is very much broken
down, especially in the interior, probably having been so disintegrated
before it was fossilized. It projects about 6 feet above the surface.
At many places about Amethyst Mountain there are numerous fragments of
fossil wood and many hollow trunks. The material in which they had been
embedded has been eroded away, and they lie around in somewhat the same
attitudes that are shown by all the trunks in the Arizona fossil
forests, but there is little doubt that they were originally erect and
have simply fallen by their own weight because of the removal of the
material around them.
Many of the trunks here, as well as elsewhere in the park, had decayed
in the center before they were fossilized, and some of the hollow
interiors are filled with clusters and rosettes of beautiful crystals of
amethyst, which doubtless suggested the name given to the adjacent
mountain. Much of this finely preserved wood, as well as the trunks
containing the crystals of amethyst, was broken up and carried away by
collectors of minerals and curiosities before the Government control in
the park was made sufficiently rigid to insure proper protection.