Weekly expositor. (Brockway Centre, Mich.) 1882-1894, 1890-10-31
a NATURAL BRIDGE OF AGATE.
some of the Wonderful Things I'm Chalco-
dony Park, Arizona.


Among the Great American wonders
Is the silicihed forest known as Chalce-
dony Park, situated eight miles south
of Corrizio, station on the Atlantic
and Pacific railroad, in Apache Coun-
ty, Arizona. The country formation is
sandstone on volcanic ash, and the
trees are exposed in gnlches and basins
where the water has worn the sand
stone away. or are buried beneath tho
sandstone, their ends protuding from
between the formations. The locality
was noticed in 1858 by the Pacific rail-
roads exploring survey. The jasper
and agate generally replaced the cell
walls and iibers, and the transparent
quartz filled the cells and interstces,
especially where the structure was
broken down by decay. These cell
centers and cavities produced condi-
tons favorable not only for the deposit
ton of silica as quartz. but also for
the formation Of the drusy crystalline
cavities of quartz and amethyst that so
increase the beauty of the material.
There is every evidence TO show that
the trees grew beside some inland sea.
After falling they became water-logged,
and during decomposition the cell
structure of the wood was entirely re-
placed by the silica from the sandstone
in the walls surrounding this great
inland sea. Maj. John w. Powell, who
has visited all these regions, says:
THE wood consisted of logs water
rolled before burial, aud are now
gradually weatherinG out of their ma
trix. The inclosing rock is sandstone
and cretaceous shale of the series
known as Jura-trias. and lying immedi-
ately above the Chinarump. Agatized
wood containing much semi-opai has
been formed in California (and possibly
in Arizona) under volcanic deposits, but
the wood in question is not associated
with volcanic material; its matriX is
sedimentary."
The red and yellow coloring matter
is derived from the oxide of iron in the
sandstone, which is red, and the black
may be due to partial carbonization or
to oxide of manganese. The bark in
nearly every case has been decayed be-
fore silicification. and even part of the
other layers of the tree is often gone
but the difference between the oxidation
on the surface and inside is that the
surface to the depth of half an inch is
so altered and changed that it has the
appearance of bark, and is generally
supposed to be such.
There is every indication that the
deposit is of considerable depth. Over
the entire area trees lie scattered in
all conceivable positions and in frag-
ments of all sizes, the broken sections
sometimes resembling Il pile of cart
wheels. A tree 100 feet in length is
often found split into as many sections
of almost uniform length, presenting
the appearance of having been sawn
asunder for shingle-bocks by some
prehistoric forester or broken into
countless fragments. ranging from the
size of small pebble to that of a fair.
sized bowlder, also fractured into per
feet shaped cubes as il cut by lapid-
arv. These multiplied fractures are
the result of alternate heat and cold,
produced by atmospheric changes act
ing on the water.in the assures of the
tree.
A phenomenon perhaps unparalleled
and the most remarkable feature of the
park is n natural bridge formed by .
tree of agatized wood spanning n canon
40 feet in width. In addition to the
span fully fifty feet of the tree rest on
one side, making it visible for length
of over 100 feet. Both ends of the
tree are imbedded in the sandstone.
1t averages l-2 feet in diameter. 4
feet ut the thickeSt part, and 3 ut the
smallest. Where the bark does not
adhere the characteristic colorS OF
jasper and agate arc seen. Although
the wood is beautiful to the naked eve
a microscope is needed to reveal its
greatest charms; not only does the
glass enhance the brilliancy of its
colors, but it renders visible the struc.
turc. which has been perfectly pre-
served even to the forms of minute cells,
auu Is more pcautlrui now than before
the transformation.
DR.. p ii. Dudley examined micro
scopically some sections of this wood
and found that part of it, at least, be-
longs to the genus Araucaria, one
species of which. Araucaria excelsa, the
Norfolk Island pine of the South Paci-
tic Ocean. according to the same author
ity, grows to height of 100 10 200
feet. Other portions we're found to- re-
semble our red cedar, Juniperus Vir-
giniana, when grown in the extreme
South. The cell structure of some of
the wood indicates growth in mild.
uniform climate. the annual rings be-
ing marked by only one. two, three, or
more slightly smaller hcXagonal or
rounded. not tabular cells. us is usual
ly the case. The name of 'Chinarump'
has been suggested for this material By
Maj. John w. Powell this being the
Indian name for the substance. These
trees. according to one of the Indian
myths, were believed to be the bolts of
the arrows used by their god. II has
been extensively used by them in
making spear and arrow points.