306 F. A, Genth—Contributions to Mineralogy. 
Cerro Colorado mine, Southern Arizona, under the impression 
that it contained a large amount of silver, and he was requested 
to acre we value of the ore, To the great 2 oe ae 
men, which he indly sae to m 
In its crystalline structure and Anes it has exactly the ap- 
pearance of specimens, furnished by the original merge! the 
Pewabic mine, Michigan. It is somewhat intermixed wit 
hornstone-like mineral. The analysis gave, after deducting 
9°52 per cent of hornstone, ete. : 
Copper, 88- s Aes! cent. 
Silver, a tra 
Arsenic, 11 46 ” 
From La Lagoona, a rancho on the road to Libertad, about 
35 miles from Saric, Sonora, where it is said to exist in con- 
siderable quantities, 
2. American Tellurium minerals.—The first rela of a 
tellurid in — country is due to Dr. C. T. Jackson (this 
Journ. [IT], vi, 188), who from some preliminary a 
supposed that from the Whitehall mine, Spotsylvania Co., 
som had been mistaken for molydenite, to be foliated ae 
ok short time afterward 2 mineral was discovered at @ 
gold mine in Fluvanna Co., Va., which much resembled that 
from the Whitehall mine. ” It was analyzed by Mr. Coleman 
Fisher, Jr. (this Journ. [IT], vii, 282), who recognized it as a 
“ telluret of bismuth,” containing a large percentage of 8é- 
lenium. 
In a cerask aes poten ee Journ, a (TTL x, 78), Dr. 
Jackson corrects his first statement and esult of an 
analysis, cowie ne Whitehall caine ts Es Geiecilynitte and 
not foliated telluri 
__In his paper he ai observed the ‘occurrence of yellow oxyd 
of bismuth, investing the nodules of the tellurium ore, which is 
not carbonate of bismuth, for it does not effervesce with acids. 
__In the year 1850, I discovered tetradymite in Davidson Co., 
N. Di. of which I published a description and analysis (this 
Journ, u ourn. [II], |, xvi, 81). I mention as associated with it a mineral, 
ey 
esulting : ts oxydation, containing tellwric acid. 
= ine my re ag to "Mineralogy (this Journ. it, a 
15), I show that the mineral from Fluvanna Co., Va. 
pase Pea Fisher, Jr., contains no appreciable quan 
& pure tertellurid tof bismut 
a 
