associated
with the coarse granite, chiefly in irregular masses or streaks, with
or without miarolitic cavities, and is the source of the topaz. The
coarse granite weathers out in rounded bowlders or flat floors. The
products of weathering are angular gravelly to coarse sandy soil
becoming finer with more extended weathering. Quartz and feldspar
grains are the principal constituents of this soil.
Two
groups of topaz deposits were examined, one about 8 miles west of
Mason, between Streeter and Grit, and the other about 8 miles west of
north of Mason or 4 miles west of south of Katemcy. In the first group
the topaz prospects of C. J. Worlie, half a mile east of Streeter, and
J. W. Bishop, 2 miles northeast of Streeter, were visited. Other
prospects were reported on the land of Dan Blick-enbach, 2\ miles
northeast of Streeter, and on Alexander Smart's place near Grit. In the
second group the prospects of Sam Await, Lee McGehee, and D. E. Amarine
were visited.
The
Worlie prospect is about a quarter of a mile east of the house in the
wash of a dry stream. All of the work has been done within a distance
of 200 feet along stream channel or within 50 feet from it. Several
small pits and diggings 1 to 3 feet deep have been made in sand,
gravel, and alluvium among large bowlders, and one pit 6 feet deep and
15 feet long was made in rock. The country rock is coarse red granite
with porphyritic texture in places. Locally there are pegmatitic phases
around miarolitic cavities. Some of the granite is friable and partly
decomposed, but much of it has weathered out into large spheroidal
bowlders, or is exposed in hard flat ledges or floors. The prospect
pits were dug through the drift to the granite floors where all
depressions and crevices were carefully cleaned out. The pit in the
solid rock opened irregular miarolitic cavities in the granite. The
minerals of value lining these cavities had been removed, but some of
the matrix was left in contact with the granite. The matrix contained
much biotite in thin flat scales ranging from small size to more than 1
inch across, a little graphic granite with red feldspar, some albite in
the form of clevelandite, gray microcline and pale amazon stone in
stout crystals, muscovite, and colorless and smoky quartz crystals.
Topaz is reported to have been found in these pockets also. The best
topaz crystals were found loose in the gravel and sand beds. Most of
these were partly broken and the edges were rounded by attrition, but
beneath the roughened surface most of the crystals were of fine
transparent quality. A few crystals were found which had not been badly
disfigured by abrasion and would serve as fine cabinet specimens Many
of the topaz crystals were tinted pale bluish or bluish green and a few
were rather strongly colored.
Several
prospects were opened on the land of J. W. Bishop. The one examined is
about a quarter of a mile northeast of the house in a low rocky hill.
The work consists of a crescent-shaped open cut 40 feet long and 4 to
10 feet deep and of another small pit about 40 yards to the southwest.
The country rock is coarse porphyritic red granite which outcrops in
large rounded bowlders and ledges The open cut was blasted out of an
outcrop of hard granite following a pegmatitic vein. This vein was
irregular in shape and carried miarolitic cavities or pockets, in which
the topaz was found. A portion of such a pocket was left exposed in one
end of the cut. It measured about 2 feet wide and 1-1/2 feet high; the
length was not exposed. It is reported
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