124 W. H. Hobbs—Mineralogical Notes. 
6, T. 47 N., R. 26 W., and is on the same vein as that portion 
of the Jackson mine in which manganiferons iron ore has been 
found. Well-crystallized manganite has been found in the 
Jackson mine and has been described by Professor E. 8. Dana.* 
Barite.—The barite from the Lucy mine is fairly well erys- 
tallized but the tabular crystals are arranged radially to the b 
axis. They average from one to two centimeters in length in 
the direction of the macrodiagonal; the habit being lath-shaped 
in this direction with the base the tabular plane. The forms 
observed are ¢c, oP (001); m,2P (110); a2 Px (100); d, 
4Px (102); 6,2 Px (010); and S,4P2 (014)? Partienlarly 
in the zone of ¢ and @ precise measurements are of little value 
owing to the radial intergrowths of individuals, and hence the 
determination of dis only approximate. In the zone of cand 
6 the following measurements were made: 
Measured. Calculated. 
CiAcO eee 001A 010 90° 65 90° 207 
Cre Loe 001A 014 1A fae BD tS 222 
The prism is easily determined to be the fundamental one 
m by being found parallel to the second cleavage. 
The crystals appear pink but the color is only superficial and 
is probably due to manganese, as the barite is associated with 
an ore of manganese. Figure 3 shows the usual development 
of the crystals. | 
Mangamte.—The manganite from the Lucy mine is in quite 
simple crystals, those which are most intimately associated with 
the barite crystals being bounded simply by the fundamental 
prism and the base. The prism angle was measured by reflec- 
tion and found to be 80° 4’, the calculated value being 80° 20’. 
These crystals are of columnar habit, 5-8™™ long, and usually 
of later formation than the barite. Other specimens of the 
substance less intimately associated with barite show crystals 
of a slightly different habit, the obtuse prism angle being trun- 
cated by the macropinacoid which has a large development. 
Rounding of the edge a, m and of the basal plane indicate the 
occurrence of indeterminate macroprism and brachydome. 
Figures 4 and 5 represent the type of manganite crystals from 
this locality. | 
* System of Mineralogy, 6th Ed., pp. 248 and 249. 
