22 Dr. Genth’s Contributions to Mineralogy. 
The results of the analyses were: 
a <8 Mean. Contains oxygen. 
ree sc SSS 83°27 33:3L i 17°30 E750 
mina, 14:54 14:13 14°34 6°70 — 998 
Sesquinyd of iron, 10°71 10°95 10°83 ea ea 
Ox f iron, ; 4-20 7-20 1°60 
pa a cerium . ..1342 IS 11 13°42 1:94 
Oxy of of ‘didymiom, ; 2-76 2°64 270 «089; ie 
0-95 15 Spe 0°68 a 
tae 1-27 11°28 11-28 ey 
0-41 0-41 O11 
Potash, , P 1:33 1°33 1:22 
Water, - 3°01 8°01 2°68 sa 268 
In the Bisnite from Orange county, the ratio of oxygen of 
YO: R203 :S8iO:, is equal to 1:08: 1-8, which is = 5:4:9, 
corresponding with the formula: 5k,Si+4#5Si, the allanites of 
Reading and Bethlehem give very ig the ratio 1:1:2, corres- 
ponding with the formula k,S8i+# 
The slight variation in the Grange county allanites of which 
the ratio of oxygen was found to be = 5:4:9 may be owing 
to small impurities of this See I believe that, when pure, it 
has, like the two others, and like all allanites which have been ex- 
amined with regard to the state of ee ve the iron in them, 
the ratio 1:1: 2, or the constitution of garn The quality of 
water in the allanites, resulting in all ec Bailey from a change, 
beginning in the composition of this mineral, as Pie sug- 
gested by Prof. Rammelsberg, was found to vary from 1-19 
cent. to 3-01 per cent.; but if we take it into consideration, the 
composition of the Orange county allanite may be expressed by 
the formula 2(R,Si+#8i)+H; that of the allanites from Bethle- 
hem and Eckhardt’s Furnace by (&,Si+-#8i)--1. 
13. T'ungstates in North Carolina. 
Tungstates having been found only at two or three localities 
in the United States, it was interesting to find them in North Car- 
olina at two localities, viz: Dr. Cosby’s mine, near Pioneer Mills, 
Cabarrus county, (a, 'b and c,) and at the Washington mine, Da- 
vidson a (d). 
am occurs in irregular lamellar masses in brown hem- 
atite sed in a hydrate of the sesquioxyds of iro manga- 
nese, which appears to be a result of the deconspagial of spathie 
iron. It is associated with scheelite, tungstate of copper, - 
eis of te 
| se Scheie i is found i in white, yohowiai white and brownish : 
e masses. ‘The 
