close
branching, form spongy masses of cylindrical shape, often somewhat
curved or spiral, and of a little less diameter than the wood cells
along which they lie. It was often noticed in a sliced thin section of
the silicifled wood that these spongy cylinders of iron oxide adhered
mostly to the same side of the wood cells which inclosed them. In other
cases, the walls of several wood cells appeared to be broken down in
the vicinity of the larger ocherous cylinders, as if by erosion,
through the agency of the organism, producing irregular cavities, now
tilled with clear quartz.
"Another
mode of growth of the fungus was well shown in many branching plants
which have insinuated themselves within the thin lamellae, which make
up the walls of the wood cells, and so have crossed over several cells
through and inside of their walls, but without entering the cells.
"The
mode of introduction of the fungus into the wood is clearly shown in
many thin veins of agate, which cross the sections and indicate cracks
in the trunk of the original tree. In these veins, as well as in the
erosion cavities referred to above, many fungus spores were observed
sprouting into mycelium, of which some of the branches were noticed
penetrating through the walls of the neighboring wood cells. From
these, as well as from other facts observed on the plant now living,
the following conclusions were drawn:
"1.
That the tree fell and was submerged in a shallow sheet of gently
running water, such as that which oozes through the cedar swamps of the
Atlantic coast down to the sea, at the present day.
"2.
The wood tissue of the tree was attacked by the water fungus
immediately after its fall, and this growth mainly progressed on the
lower side of the cells in the prostrate tree. After the decay and
loosening of the bark, the floating spores of the fungus evidently
made their entrance into the tree, through the cracks in its trunk.
"3.
The slowly moving current under the swamp brought by infiltration into
the wood cells a constant supply of water, charged with organic salts
of iron, etc. The coloration of the wood has been effected, not by
chemical or mechanical agency, but entirely by organic secretion and
deposit of ferric oxide, etc., by this interesting species of water
fungus.
" i. The
complete silicification of the wood finally ensued, with a deposit of
the chalcedonic and crystalline quartz, producing varieties of jasper,
banded chalcedony, ruin agate, etc.
"
In the silicifled wood from Barillas Springs, Texas, still more
delicate and complex forms of the same fungus were detected in a
perfect state of preservation."
Opal.—In
August, 1890, Mr. James Allen, a jeweler, of Tonkers, New York,
detected what proved to be fire opal in a heap of rocks thrown out in
digging a well, from a depth of 22 feet, on the farm of William Leasure, near Whelan, 20 miles southwest of Colfax, in Washington
