In Douglas County1 there
are large masses of serpentine, one crossing Little River near Peel, 15
miles east of Roseburg, and another trending northeast and extending
from a point near Riddles on Myrtle Creek to Brushy Butte. There are
several smaller masses in the region between the two larger masses.
There is also a considerable body of serpentine forming Sexton
Mountain, northeast of Merlin and Hugo.
Several of the copper mines in the peridotite-serpentine area of Douglas County produce platiniferous ore.
In Grant and Baker counties of eastern Oregon serpentine, according to Lindgren,2
"forms large areas in the vicinity of Robinsonville and Bonanza, in the
eastern part of the Greenhorn Mountains, at Susanville, and in the
Strawberry Range south of Prairie and Canyon. The serpentine is an
altered form of gabbro, perhaps also peri-dotites." Pardee and Hewett3
state that dikes of dunite, porphyry, and pyroxenite are widely
distributed in the Sumpter region. Chro-mite and platinum have been
reported in the placer gravels of various streams in the Blue
Mountains and from the Spanish Gulch mining district, south of
Dayville, in the extreme eastern part of Grant County.
Press reports 4
in June stated that a blind lead, opened by a deep tunnel at the
Compton mines, Susanville, Grant County, carried 1.10 ounces of
platinum and $4.40 gold a ton.
It has been reported 5 that platinum has been discovered in the black sands of Buck Gulch, near Sumpter, Baker County.
Late
in 1916 T. W. Gruetter informed the Geological Survey that he was
instalhng a custom plant for the recovery of platinum from concentrates
at Kerby, Josephine County.
UTAH.
Recent developments at the horseshoe bend of Green
River, east of Vernal, Utah, indicate that the placer deposits may be
worked. The gravels at this place carry some platinum and gold, though
both metals are in very fine particles and are difficult to save.
Platinum has been detected in the gravels of Colorado River near Hite.
below the mouth of Green River. Several attempts to mine these deposits
on a large scale have not proved profitable, doubtless owing in part to
the great difficulty of obtaining supplies in this inaccessible place
and in part to the difficulty of saving platinum so finery divided and
in such small quantity.
WASHINGTON.
In
July, 1916, samples of placer concentrates were received by the
Geological Survey from a deposit near Riverside, Okanogan County,
Wash., which contain platinum in considerable proportion. Apparently
the platinum comes from a broad belt of chromite-bearing serpentine
that lies west of Okanogan River and extends from a point near
Oroville, Wash., to and beyond the Canadian boundary. Plati-
« Diller, J. S., U. S. Geol. Survey Geol. Atlas, Roseburg folio (No. 49), 1898.
2 Lindgren,
Waldemar, The gold belt of the Blue Mountains of Oregon: U. S. Geol.
Survey Twenty-second Ann. Kept., pt. 2, p. 589,1901.
3 Pardee,
J. T., and Hewett, D. F., Geology and mineral resources of the Sumpter
quadrangle, Oreg : Oregon Bur. Mines and Geology, vol. 1, No. 6, p.
38,1912.
• Eng. and Min. Jour., June 24,1916. Min. and Eng. World, June 17,1916.
