pee eae me Tet ee. 
J. L. Smith on new localities of Minerals, etc. 67 
laminz; but from careful examination of the process of decom- 
ition, there is no doubt that the interior of the mass will not 
differ materially in its composition from the analysis already 
given of the nickeliferous iron. Besides the minerals already 
mentioned, and which properly belong to the original mass, there 
is much oxyd of iron, rie gee some nickel arising from the 
ecomposition of the su 
Art. TX.—On a new locality of Tetrahedrite, Tennantite, and Na- 
crite, with some account of the Kellogg Mines of Arkansas; by 
Prof. J. LAWRENCE SMITH. 
A SHORT time since Prof. E. T. Cox of Indiana sent to me an 
antimonial copper ore containing silver, one fragment being the 
termination of a crystal having a number of small but beautiful 
aces, another was a minute crystal of a different form; in the 
hands of Prof. Cox a blowpipe analysis had given about five 
per cent of silver in some of the mineral. 
The crystalline fragments were first examined and they enabled 
me clearly to trace out tetrahedrite in one and tennantite in 
the other. The faces on the tetrahedrite were small but beauti- 
ful and very numerous; from the number on the fgment ex- 
amined there would not have been less than from 60 to 70 had 
the crystal been perfect : it corresponds very nearly to the diss 
figured in Dufrenoy’s Mineralogy, plate 124, fig. 441, which he 
speaks of as coming from Moschellandsberg, a locality that I am 
not able to discover. Good measurements were made on a few 
of the faces. 
P on P 70°; P on 5% 159° 30’; P on a? 144° 30’ 
Specific gravity of different specimens varied from 4°78 to 
5-08; the latter was the sp. grav. of the above crystal. The 
analysis of two specimens, No. 2 being a part of the crystal, 
gave 
Antimony, = - - 26°50 27°01 
Sulphur. - - 26°71 25°32 
Copper, - - + 36-40 33-20 
ime, ec es 1:89 82 
ma 4-20 6.10 
Silver, - - - 2°30 4°97 
Arsenic, -  —- 1-02 “61 
98:03 
The quantity of No. 2 analyzed did not exceed 800 milli- 
grams. 
