614 The American Naturalist. [July, 
Hills in Dakota for some six years past, the first accurate account of 
its occurrence and of its composition has but just been communicated 
by Mr. Headden.' The mineral together with tantalite is often pres- 
ent in the stream tin of the hills. It is also found imbedded in beryl 
at the Etta Mine and associated with other minerals at the various 
other mines in the district. Fourteen analyses of crystals obtained 
from the different localities are given. Some of these correspond with 
the formula 3R Cb,O, + 2R Ta,O,, with R = Fe, Mn, As the den- 
sity of the mineral becomes greater the proportion of tantalum to 
columbium increases, passing from 1:6 to 1 : 14; thus indicating 
that columbite and tantalite are isomorphous substances. Analyses 
follow: I. Turkey Creek, Col.; II. Yolo Mine, S. Dak.; III. Tanta- 
lite, associated with stream tin at the Grizzly Bear Gulch, S. Dak.; 
IV. Manganiferous columbite, from Advance Claim, 14 miles S. of 
Etta Mine. 
Cb,O, Ta,O, SnO, WO, FeO MnO CaO Sp. Gr. 
d ADAD 2274 ak CILIA TABQ). O40. Ok. 6.886 
II. 24.40 57.60 Al 14.46 2.55 .73 6.592 
Il. 3.57 82.23 32 12.67 1.83 8.200 
IV. 47.22 34.27 32 1.89 16.25 6.170 
Mr. Headden’s results are interesting as indicating the widespread 
occurrence of these two rare minerals in the Black Hills region, and 
his paper is valuable for the great number of analyses contained in it. 
Laspeyres’ has reexamined the saynite (of V. Kobell) from Grube 
Griineau, in Kirchen on the Sieg, in Germany, where the mineral 
occurs in crystals. He finds it to be a mixture of polydymite with 
other sulphides, as he declared it to be some time since. Ullmanite 
crystals from Siegen, in the same neighborhood, are described as con- 
sisting of cubes with striations parallel to the pyritoid edge, or of 
cubes, dodecahedrons and octahedrons combined with more complica- 
ted forms, among which are many parallel hemihedral ones. Its erys- 
tallization thus corresponds with that of the Sardinian Ullmanite 
described by Klein.’ A rare chance was also afforded Laspeyres for 
the study of the crystallization of wolfsbergite, from Wolfsberg, in the 
Harz. The new crystals obtained by him are tabular parallel to oP, 
1Amer. Jour. Sci., Feb., 1891, p. 89. 
*Zeits. f. Kryst, xix, 1891, p. 417. 
5Neus. Jahrb. f. Min. etc., 1883, i, p. 180 and 1887, ii, p. 169. 
