Cii.w. XXX [.J 
.rUAUUA : KAJLIDONGRI. 
681 
Judging from the examples of spessaitite-bearing rock partly altered 
to maii>rancse-ore, and of manganese-ore containing 
residual spessartite, so oiten seen m the parts ot 
the deposit north of the waist, it seems probable that the portion of the 
ore-body north of the waist has been formed, at least in part, by the 
chemical alteration and replacement of the manganese-silicate-rocks 
of the gondite series. 
In view of the apparent absence of spessartite and rhodonite in the 
part of the deposit south of the waist, we must conclude either (A) that 
the alteration and replacement processes were more complete here, so 
that no trace of these silicates is now left ; or, (B) and perhaps more 
probably, that this part of the deposit was not sufficiently metamor- 
phosed for the development of manganese silicates to take place. In 
the latter case the part of the deposit south of the waist probably con- 
sists partly of original fairly pure manganese-oxide sediments since 
compressed, and is partly a replacement deposit formed at the expense 
of the quartzites from materials brought either from the part of the de- 
posit north of the waist or from buried portions of the deposit. 
As evidence for B it may be mentioned — see also the sections, Plate 
19 — that in many parts of the deposit, especially south of the waist, the 
manganese-ores and quartzites are interbedded, suggesting that they were 
deposited as alternating layers of sand and manganese oxide. Only a 
portion of these manganese-oxide layers can be original, however; for 
1. The bands of ore and quartzite are not usually continuous for 
any distance, a band of ore giving place to quartzite and 
vice versa. 
2. Many examples can be found of the gradual replacement of the 
quartzites by manganese-ore, the change being first noticed 
in the appearance of spots of manganese-ore in the quartz- 
ite. 
3. Residual nodules of quartzite, like those seen at Balaghat, can 
be found in places in the manganese-ore bands — e.(j., in 
cross-cut 4 — , indicating that these bands have arisen by the 
replacement of an original quartzite band. 
Numerous fissures — probably formed during the folding of these 
rocks — have been filled with vein deposits, which contain such minerals 
as hoUandite, barjd^es, and arsenates. 
