Chap. XXX.] 
SANGM : CIIIK-V ADVATI. 
645 
by Major T. W. Collis Barry, I. M.S., of 10 of the best samples taken from 
10 different pits. The assays show the following limits and mean : — 
Limits. 
Mean. 
Manganese peroxide (MnOo)' ..... 
30-77—60 
86 
19-45— .-58 
■18 
31-6 
Ferric oxide ........ 
19-0 —30 
2 
Iron ......... 
13-3 -25 
3 
l()-8 
Siliceous residue ....... 
7 -31 
19-2 i 
It is seen from this that even the best ores are much too siliceous and 
low in manganese to be of any value, except possibly where a very silice- 
ous ferruginous manganese-ore might be desired. The quantity of ore 
available was also found to be very small, so that, as already mentioned, 
the Bombay Company, Limited, finally decided that the ore does not 
exist in paying quantities. 
Mr. Maclaren's specimens show that the ores both at Chile- Vadvati, 
and at Kelur immediately to the S.E., consist of pyrolusite and 
psilomelane, intimately associated with banded hmonitic jaspery quartz- 
ites, from which they have been formed by gradual replacement. Under 
the microscope this replacement is seen to take place by the gradual 
extension of a network of veins of manganese-oxide through the very 
fine-grained quartz mosaic. These veins gradually increase in thick- 
ness, reducing the enclosed areas of quartz to smaller and smaller dimen- 
sions, until the replacement may become complete. This stage is, how- 
ever, not usually reached and it is the residual quartz patches that 
account for the large siliceous residue returned in the assays given 
above. Vein-quartz is replaced in the same way (see Plate 13, fig. 3). 
The occurrence and mode of origin of these ores is in fact practically 
identical with that of the manganese-ores of the Jabalpur district, and 
consequently, as in the latter area, the ores — 
(1) are very irregular and patchy in their distribution, 
(2) occur only at or close to the surface, 'j 
(3) are of very variable quality, 
(4) are usually of too low grade to be used for export purposes. 
1 It is probable that the manganese was determined as peroxide. It does not neces- 
sarily follow that it was all present in this form in the ore. 
D 2 
