W. H. Hobbs—Mineralogical Notes. 125 
An analysis of this mineral has been made by Mr. Herman 
Schlundt, Assistant in Chemistry at the University of Wiscon- 
sin, with the results given below in column I. In column II 
is given the theoretical composition of manganite and in col- 
umn III the recalculated analysis with barium, calcium and 
magnesium, and hygroscopic water deducted. 
4, 5, 
——<f5 = Sage ACH Ge 
+ 
uf LT. TET. 
BP eee d eS oe 60°29 62°42 62°36 
H,O (Hygroscopic) - ---- 06 sen cee 
H,O (Combined) ....-.- 10°04 10:24 10°39 
BaCO, and CaCo, -.--- ‘58 ets ea 
RierC Opec. be os 2°98 ae Be 
O77 Calculated)... = -.-- 26°35 27°34 27°25 
MiGente oe oe 100°30 100°00 100°00 
A specimen of manganese ore from the Bonnie mine, Michi- 
gan, recently donated to the University of Wisconsin by John 
EK. Burton, Esq., of Milwaukee, is quite pure manganite. A 
portion of the specimen exhibits rounded orthorhombic crystals 
not unlike the Lucy mine crystals, but these are less perfect 
and altogether unsnited to measurement. 
3. Chloritoid from blocks on the South Shore of Michigamme 
Lake, Michigamme, Mich. 
This mineral is included in specimens of a phyllitic schist 
which were collected by Dr. Van Hise from blocks on the south 
shore of Michigamme lake, Michigamme, Michigan. The 
blocks are very abundant and are often as large as a good sized 
room. Professor Van Hise feels sure that the rock will be 
found 2m si¢w in the near vicinity of the blocks, probably in 
the bed of the Michigamme river. 
Thin sections of the rock show it to be largely made up of a 
colorless mica in fine scales, through the mass of which are dis- 
tributed large flakes of biotite. The latter are not arranged 
with reference to any particular direction, but sometimes assume 
