B. Silliman—Mineralogical Notes. 199 
the usual associates of silver ores the world over. All these 
lodes abound in eM matter, but there are no limestone 
beds in the vicinity ; and in the absence of any organic remains, 
we are ignorant of the orobatle geological horizon. 
“The Hamburg” mine has furnished the most numerous and, 
on the whole, the best specimens of sa The crystals 
ge-red—deeper than potassium 
to reddish-yellow and brown. They are always highly lus- 
trous. The size is small, the length being not over two milli- 
meters and usually less than one; and the diameter about half 
the length to equal dimensions. The hexagonal prisms are 
modified usually by one, sometimes by two planes on each term- 
inal edge, and occasionally the angles are replaced. These crys- 
tals are implanted singly and in crusts on a dark chocolate- 
colored siliceous gangue, with occasional obscure crystals of 
cerussite, and rarely a dark-colored cleavable lime-rock (impure 
calcite). 
The ‘Red Cloud” mine furnishes eR HER of a rich — 
red or flame-color, associated with beautiful orange-red wulfe- 
nite. At the depth of 280 feet, ‘neeied on the slope of. the 
vein, ga ovm takes the place ‘of vanadinite almost to its ex- 
clusion. The crystals of vanadinite at this mine are smaller 
and grouped in more confused masses than at the Hamburg 
oA “the Princess” mine, the re ale occurs in slender crys- 
tals of a brilliant red color almost identical with that of croco- 
ite, implanted upon white calcite. The habit of the species is 
unlike either of those before mentioned; the crystals are at 
least four diameters long and are very slightly modified. 
They are not over half a millimeter in diameter, but are very 
perfect in form, luster and color. They have, naturally enough, 
been mistaken for chromate of lea 
he genesis of the vanadates of these mines is obscure, 
single small specimen only of the galena has reached me. It 
forms the nucleus of a surrounding mass of amorphous angle- 
site, upon the outer surface of which appear obscure cru usts of 
vanadinite. Analyses of a series of samples selected on the 
spot, 2h a Sen examination might reveal the origin of the 
-vanadic 
Vulture i aliobriok, as I have called it, another and quite dis- 
tinet district in Arizona, has furnished, at a number of places, 
or ae ge with other rare species. This area embraces? the 
Jour. oo Series, VOL. XXII, No. 129.—SepremsBer, 1881 
