54 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [PaRT I : 
original manganiferous sediments. It is probable, as far as can be 
judged from the careful study of the specimens collected, that braun- 
ite, which is often the predominant mineral in these deposits, has been 
formed in both ways. At one locality in the Central Provinces, namely 
Kacharwahi in the Nagpur district, braunite crystals are found in 
abundance in an albite-rock that is probably intrusive in the ore-body. 
Hence we see that the Indian braunite has been formed in three distinct 
ways, as follows : — 
1. By crystallization from an igneous intrusive ; at Kacharwahi. 
2. By the metamorphism of manganiferous sediments ; in the Cen- 
tral Provinces, Central India (Jhabua), and Narukot. 
3. During the chemical alteration under the influence of waters — 
probably heated, and containing chemical reagents and solvents — of 
manganese silicates, sach as manganese garnets and manganese-pyroxenes, 
these silicates being contained (a) in the igneous rocks of the kodurite 
series in Vizagapatam, and ( o) in the metamorphic rocks of the gondite 
series in the Central Provinces, Central India, and possibly Narukot. 
There is no certain evidence of the occiirreiice of this mineral in 
any other areas in India, or in rocks of any other age, than those men- 
tioned above. It must be mentioned, however, that minute specks 
of a crystalline mineral sometimes showing octahedral faces are occa- 
sionally seen sparsely distributed in the ores of other areas, especially 
the Sandux Hills. This mineral may also be braunite, but has not 
been investigated, and is perhaps more likely to be magnetite. 
In view of the enormous quantities of this mineral that exist in 
India it might be thought that abundance of material would now 
be available for the convenient study of the crystallographic characters 
of this mineral. Such, however, is not the case, the mineral being 
only rarely found in measurable crystals. In the Vizagapatam deposits 
it usually occurs as specks and patches of irregular shape embedded 
in a matrix of psilomelane. In fact I have not obtained from this area 
a single specimen showing crystal faces. In the deposits of the Central 
Provinces, Jhabua, and Narukot, the mineral usually occurs in one of 
two forms. One of these is a finely granular aggregate in which all 
the grains are braunite pressed one against the other, but showing 
a tendency to a general octahedral shape. The other is a rock composed 
of a mixture of braunite and psilomelane, little granules of the braunite 
being set in a matrix of psDomelane. ( Plate i shows a photo- 
micrograph of a pohshed and etched slice of such ore.) The proportions 
