364 The American Naturalist. April, 
penetrates its mass. The composition of natrophilite, as determined 
by Mr. H. L. Wells, is: 
P.O, MnO FeO Na,O Li,0 MO Loss 
atig § 38:19" 3.06 16.79 19 43 81, 
essentially NaMnPO,. The new mineral is regarded as but another 
one of the very interesting substances produced by the alteration of 
spodumene and lithiophilite. The triphylite group as now known con- 
sists of triphylite Sextet lithiophilite (LiMmPO,), and natro- 
philite (NaMnPO,), sides many intermediate compounds.—— 
Rosenbuschite, nordenskjoldite, and melanocerite have been described by 
Brégger 6 from the syenite dykes in the vicinity of the Langesunds- 
fiord, in Southern Norway. The first mineral is found in radial groups 
composed of monoclinic fibres with cleavages parallel to oP, œ% Poo 
and 2Pæ. The axial,ratio is a: b: c = 1.1687: 1: .9775. f==101° 
47’. The acute bisectrix is 4. The obtuse bisectrix is inclined 36° to 
c in the acute angle f. Double refraction strong. The mineral is 
easily fusible, and is decomposed with strong hydrochloric acid. It 
is light orange gray in color, and is weakly pleochroic with C> B> 
A. Its specific gravity is 3.31 and hardness 5-6. In morphological 
properties and in composition it is apparently a zirconium gectoltte. 
siO, ZrO, TiO, Ti,O, Fe,O, La,O,. DIED: MnO CaO Na,O Los 
31-53 18.69 6.07 t.31 Se To 2.38 1.85 25.38 10.15 - 

Nordenskjoldite is a calcium-tin-borate with the composition se 
Sn (BO,),]: 
SnO, ZrO, CaO B,O, Loss 
53-75 -go 20.45 23.18 Lya 
It crystallizes rhombohedrally with a: ¢ = 1 : .8221, and is tabular in 
habit. It is sulphur yellow in color, is transparent, optically negative 
and strongly doubly refractive. Its hardness is 514-6 and Sp. Gr. 4.2. 
Melanocerite is also rhombohedral with a: ¢ = 1: 1.2554. It occurs 
in tabular crystals of a deep brown or black color. Their double 
refraction is negative, hardness 5-6, and specific gravity 4.129. 
Chemically the mineral is a complicated compound of the rare earths 
with silica, tantalum, boron, and fluorine.-——Cohenite is described 
by Weinschenck ” from the meteoric iron of Magura, Hungary. When 
dissolved in hydrochloric acid the meteor leaves a residue in which lit- 
tle prismatic tin white crystals are discovered. These turn brown when 
16 Geol. För. i. Stockholm Férh., IX., 1887, p. 247. Ref. Neues Jahrb. f. Min., ett., 
1889, II., p. 432. 
Ann. K. K. Naturh. Hofmus., Wien., IV., 1889, p. 94. 
