132 B. Silliman—Mineralogical Notes 
yellow covered with druses of small crystals of anglesite, 
which are quite colorless, brilliant and transparent. The 
masses are banded like agates. Its density is 6:08, and its pyro- 
gnostic characters are those of anglesite. It contains on an 
average of mining samples about 55 ozs. of silver to the ton of 
2,000 Ibs., which is materially less silver than is found in the 
unchanged galena. The “bullion” (silver lead) of this mine 
as sent to market contains about 120 ounces of silver to the 
net ton. My informant for these economical facts is Mr. F. F. 
Thomas, a graduate in Arts and Science at Yale, who is in 
charge of the smelting works at these mines.* 
10. Platinum and Iridosmine—Since the publication (this 
Jour., v, 384) of my note on the crystalline sands of the Chero- 
kee gold washings in Butte county, California, I have obtained, 
through the kindness of Mr. G. A. Treadwell, who at my - 
to be new (this Jour. IT, 246), which he described as occurring 
among sands from California, in 1858, was not successful. 
Mr. Glass, the resident manager, informs me that the plati- 
num and its associate minerals are quite abundant at Cherokee, 
but as the quicksilver does not amalgamate them they have no 
means of escape from the mechanical force of the stream which 
washes away much the larger part, thus entailing a loss which 
there is no means now known to prevent. 
fornia by Blake and others, among especially the sands of the 
gon. But I believe this is the first notice of their being found 
in the older deep placers now so extensively worked by the 
hydraulic process. : 
The “' Black Sands” of the Cherokee dee placer washings I 
find to be composed chiefly of chromites. The magnet selects 
a sparingly a few crystals and masses of magnetite, some of 
them being also strongly magnetic. An occasional mass © 
The co pact anglesite from ny 
m 
i described by Prof. Brush in this Journal, 
qi, v, Cerro Gordo mineral. 
m) 
421) is not distinguishable from the 
