1)58 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [PaRT IV : 
This indicates the ore to be composed of a mixture of braunite and psilo- 
melanc (or hollandite). Stated in the usual way the analysis is as 
follows : — 
Manganese 
Iron 
Silica 
Phos|)horus 
Moisture . 
50-78 
5-42 
5-45 
0- 09 
1- 32 
Piedmontite is very abundant in many of these limestones and in 
Piedniontitc and pied- Some places occurs in nodules up to 1 inch in 
niontite.gneiss. length. Sometimes it is uniforml)^ distributed 
through both pale-coloured limestones and gneisses in such abund- 
ance that the rock appears pink. In some specimens collected, pied- 
montite is found in a fine-grained rock composed of plagioclase, ortho- 
clase, and quartz, with a little mica, some spessartite, and abundance 
of apatite and sphene. Secondary calcite is being formed at the 
expense of the felspars, and this rock is taken as evidence that the 
piedmontite-bearing and other manganiterous limestones have been 
derived from original piedmontite -and spessartite-bearing gneisses, 
in the same way as the crystalline limestones of Class I of the Chhind- 
wara district (the pale-coloured crystalline limestones of the Nagpur 
district) are regarded as having been derived from original quartz- 
pyroxene-gneiss\ See also Part II, pages 300 — 303. 
Both ends of the outcrop of these limestones are obscured by allu- 
vium. The total length is about 1,400 yards and the breadth varies 
from 60 to perhaps 100 yards. The mineralization is irregular, but 
generally speaking, the black limestone, its silicified form the black chert, 
and the limestone containing lenticles of manganese-ore, occur about 
the middle of the thickness of limestones. 
Several small pits had been dug by Messieurs Jambon & Cie., at vari- 
ous points along the outcrop. They revealed either the black limestone, 
the black chert, or the manganese nodules. At 
about where the strike of the limestones changes 
from north-north-east to east-north-east, a large pit (shown in Plate 42) 
had been excavated. It was of irregular shape, some 45 paces long by 10 
broad, and showed an imevenly weathered surface of crystalline lime- 
stones, of which portions had been dissolved away leaving upstanding 
pillars and masses of limestone between. The banding of these limestones 
had also been brought out by the differential weathering, the bands 
containing accessory minerals, such as pyroxene and epidote, standing 
out as ridges, while the bands composed mostly of calcite were repre- 
sented by furrows or grooves between these ridges. This is well shown 
The workinijs. 
1 Fermor, Bee. Q. S. I. XXXIII, pp. 168—170. 
