River could be readily washed by hydraulic methods for which power
pumps would be required. Between the peridotite outcrop and Little
Missouri River is a large area of bottom land which may prove to be
workable placer ground.
a small amount of prospecting was done on the property of the American
Diamond Mining Co., but Mr. Fuller states that the company reports the
finding of one stone.
The best information on the diamond-bearing peridotites of Pike County has been given by Hugh D. Miser.1 This report contains a carefully
prepared map of the known peridotite exposures, with sections and
detailed information concerning them. A good resume of the developments
in the diamond field during 1913 has been given by John T. Fuller.2
M. J. Cooney, of Oroville, Cal., reports the finding of a first quality
white diamond by John McGregor on the old placer grounds of the U. S.
Diamond Mining Co., at Cherokee, in December, 1913, and of several
other smaller stones of inferior quality in the same area. Mr. McGregor
states that the stone weighed 1| carats and is valued at $75 in the
Press reports 3
mention a diamond found by Ed. Bryan, a miner at Sawpit Flat, in Plumas
County, Cal. In a personal communication Mr. Bryan states that the
stone was very similar to a diamond found at the same locality several
years ago and known to be authentic. Both stones were found in old
hydraulic mining ground similar to the old placers of Butte County,
where a number of diamonds have been obtained. Through misplaced
confidence the stone was lost to Mr. Bryan before he could be positive
of its determination.
Frank E. Johnesse, of Boise, Idaho, reports the discovery of three
small fragments of diamond in the Rock Flat mine in Adams County,
Idaho. The largest of these fragments weighed a little less than
one-eighth of a carat. The diamonds were found during placer mining for
gold. Other possible gem minerals in the form of sapphire, garnets, and
zircon are also found in the clean ups. Robert N. Bell, State mine
inspector of Idaho, states that the rock formation of this area is
chiefly gneiss with a dike rock of basic composition which has
weathered to a soft yellowish earth in places. Mr. Johnesse is
installing a hydroelectric plant to treat the concentrates from placer
mining for the various minerals of value they may contain, such as
monazite, zircon, etc.
Messrs. Perry Bradford and R. L. Royse, of Centerton, Ind., have
furnished information concerning the finding of five diamonds during
1913 on Gold Creek and Highland Creek, in Morgan County. Two of these
were found by Hugh Marshall, two by Fred Doyle, and
areas of diamond-bearing peridotite in Arkansas: U. S. Qeol. Survey
Bull. 540, pp. 534-546,1914. 'Eng. and Min. Jour., Jan. 10,1914.
■Sacramento Union, Cal., Aug. 17,1913.