Geology and Mineralogy. 2738 
He obtained Si 53°65 Al 2-25 Fe 2-48 Mg 16-00 Oa 23:05 =100, with 2°57 
p. ¢. of hypovanadie acid. 
16. On Sellaite, a new native fluorid, by Dr. Struver, Atti della 
R. Accad. di Torino, iv, 1868, 35.—This mineral was etected on a 
specimen of anhydrite from Sito duli in the State of Maggiore, 
in nse: On the anhydrite there were also crystalline sul- 
r, dolomite, and rare twins of albite. It is tetragonal in crys- 
tallization, with I on 1 (oP on P)=123° 30’, and 77 on 7-3 (or 
a Po P3) =161° 34’, Cleavage parallel to I and 7-¢ perfect. 
aes: °G. aa 972 at 24° C. Fracture conchoidal. Luster vitreous. 
Colorless. Transparent. Powder white. 
t is insoluble in water; also in acids, except concentrated sul- 
phuric, which causes an evolution of fluohydric acid, Small frag- 
nts melt in the flame of a candle with intumescence. From the 
sianty of its reactions to those of fluorite, the author concludes 
improbable that the mineral is a monofluorid of magnesium, 
which contains 38°71 of magnesia and 61°29 of fluorine. In treat- 
ing a small fragment of it with concentrated sulphuric acid, he 
obtained for the proportion of magnesium 39°64 p.c. The small 
amount of the mineral in hand prevented his making a complet 
analysis. The species is named after the distinguished cegatsllog: 
a QuUINTINO SELLA. 
mbrosite.—C. U, Suzparp describes under this name, in 
The Rural Carolinian, Feb., 1870, p. 311, a resin resembling amber, 
sinks slowly in water; an ts into a clear liquid at 460° F., 
after softening at a much lower temperature. I c 
yellowish-white light and pleasant odor, and tabi no a behind. 
The name is made from the two words am 
18. On the Guanape Island Guano and its mi “ik by Yr 
and veins in the Guanape Guano, havin ae 5, G.=2°3, and 
resembling a little the red Cheshire rock-salt, but rhombic ‘detendl 
of cubic in cleavage, is called Guanapite the author. He foun on 
it to consist of sulphate of potash 67°75, sulphate of ammont 
27°88, oxalate shoe ammonia 3°75=99°38. It "loses ammonia slightly 
on exposure e air. 
Another sibetaane from the Guano is named Guanowalite. It 
contains gona of potash 40°20, oxalate of ammonia 29°57, water 
0°46 =100°23, It occurs as pseudomorphs of a bird’s egg, hav- 
lea 
color; somewhat pegs luster; feeble Easilebeane + para ss be- 
- 2 — i When heated it swells up, blackens, gl 
tially fuse off ¢ copious fumes of ammonia, and leaves 
whits ieeitne 6 of "oulphate of potash. 
