854 The American Naturalist. [September, 
to be orthorhombic. They are raven black and perfectly opaque even 
in the thinnest sections, They are easily soluble in hydrochloric acid 
and are not magnetic. An approximate analysis gave: FeO — 26; 
Mn,O,— 44; Sb,0,+ H,O = 30 Neotesite, also from the Sjégru- 
fvan, occurs in lamellar masses associated with tephroite, pyrrhoarsenite, 
and calcite. It resembles in appearance red orthoclase. It has a good 
cleavage, a hardness of 5-5.5. It is soluble in acids, leaving a residue 
of flocculent silica. Its composition : 
SiO, MnO FeO MgO H,O 
29.50 40.60 tr. 20.05 9.85 
corresponds to (MnMg),SiO,+H,O, £.«, to a hydrated tephroite. 
The author, however, does not regard it as a decomposed tephroite. 
Antlerite is a light green, massive mineral from the Antler Mine, Mo- 
have County, Arizona, which, according to Hillebrand, has a specific 
gravity of 3.93, and a composition as follows: CuO-2 67.91; ZnO— 
16.5; CaO —.o5; SO,— 20.77 ; H,O — 10.93, corresponding to 3 
Cu SO, 4- 7 Cu(OH),. Selen-tellurium, from El Plomo Mine, Teguci- 
galpa, Honduras, is nearer in composition to native selenium, accord- 
ing to Messrs. Dana and Wells," than any substance known. It is 
regarded as an isomorphous mixture of the two metals indicated by its 
name, in the proportions Se= 29.31, Te= 70.69. It occurs massive, has 
an indistinct columnar structure, and is blackish-gray in color. Its 
cleavage indicates hexagonal crystallization. Durdenite, a greenish- 
yellow mineral associated with native tellurium, is thought by the 
same authors to be a ferric tellurite corresponding to Fe,(FeO,),4- 
4 H,O, but differing from the ferric tellurite described by Hillebrandt 
under the name emmonsite, Hamlinite.—Messıs. Hidden and Pen- 
field ? describe a rhombohedral mineral occurring at Stoneham, Maine, 
in small crystals, associated with herderite, margarodite, and bertran- 
dite. The material available for study was so small that no chemical 
analysis of it was possible. The crystals are bounded by oR, R, and 
—2R, with oR predominating, @:c=1:1.135. The cleavage is per- 
fect, parallel to the base, and the lustre on this face is pearly, while 
on the rhombohedral faces it is vitreous and greasy. The double re- 
fraction is weak and positive. Hardness=4.5 ; Sp. Gr.—3.228. Blow- 
pipe tests prove the mineral to be a phosphate of beryllium and alum- 
inum containing fluorine. Phosphosiderite is a new mineral from 
10 Bull. U. S. Geol. Survey, No. 55, p. 48. 
11 Amer. Jour. Sci., July, 1890, p. 78. 
12 Amer. Jour. Sci., June, 1890, p. 511. 
