Mineralogy and Petrography. 169 
Alf. Gerhard ' calls attention to the fact that most of the rocks 
described as soda-granites are really ordinary granites in which 
the proportion of sodium is little greater than is usually found in 
granites. The Ulfserud (Sweden) rock, however, appears really 
to contain a plagioclase approaching very near to albite in com- 
position. 
MINERALOGICAL NEws.—Dihydro-thenardite is the name given 
by Markownikow’ to a substance found ina thin colorless bed on 
the shore of Lake Gori, in the Gouvernement Tiflis, Russia. In com- 
position it is a sodium sulphate differing from thenardite and mira- 
bilite in appearance and its content of water. An analysis 
yielded 16.15 per cent. of water, corresponding to the formula 
Na, SO, + 2 H,O. It crystallizes in the monoclinic system.—Laist 
and Norton! report the occurrence of a new antimonide from near 
Mytilene, Asia Minor. The new mineral resembles silver in color 
and lustre. It is massive and brittle. Its hardness is 4.-5. and its 
specific gravity 8.812. Upon analysis it yielded: Cu = 73.37 
per cent., Sb = 26.86 per cent., corresponding to Cu,, Sb, (breit- 
hauptite = Ni Sb, dyscrasite = Ag, Sb- Ag, Sb.)— A Barium 
manganite from near Austinville, Wythe county, Virginia, accord- 
ing to Mr. Walker,’ is of the following composition : 
Mod: RO BO SiO, (FeO. ALO) 
68.86 7.51 14.42 5.08 1,98 2.23 
It is found imbedded in psilomelane and ferruginous clay in the 
form of “radiating fine fibrous needles.” Its color is brownish- 
black. Hardness = 1.5. Sp. Gr. = 3.27. It differs from var- 
vicite (Mn, O, + H, O) and lepidophzite (Cu Mn, O + 9 H, O) 
m ey E: 
ROSENBUSCH’S “ MASSIGE GESTEINE.”—The second portion of 
Professor Rosenbusch’s Massige Gesteine? fully sustains the good im- 
pression produced by the first part. This concluding portion of 
1 Ib., 1887, ii., p. 267. : 
* Jour. d. russ. phys.-chem. Gesells. 1887 [I], p. 252; Ref. Ber. d. 
deutsch. chem. Gesells., 1887, p. 546. 
s oon aon Jour., X., Jan. 1886, p. 60. 
ie 
* Neues Jahrb. f. Min., ete., 1888, i., p. 65. 
: Amer, Jour. Sci., Jan. 1888, p. ol. 
ent ikroskopische Physiographie der Massigen Gesteine, 2 Abt. Stutt- 
ê American Naturalist, Feb. 1887, p. 172. 
