Chap. XXXIX. 
GANJAM : BOIRANI. 
1035 
r Psilomelano in which the limonitic material is small in extent. 
fi" Psilomelane, mostly nodular or botryoidal and containing but a wmall 
amount of limonite. 
(>" Psiloiuohmo gradually passing downwards into: — 
Soft limonitic rock of unknown thickness, spotted and latched with soft 
black manganese oxide. 
To judge from specimens collected there can be no doubt whatever that 
the ore is the result of the replacement of felspar-rock or of felspar- 
quartz-rock by manganese oxide, and that the underlying limonitic 
rock is the result of replacement of quartzite by iron oxide. It seems 
a fair deduction to suppose that the replacing manganese has come 
from the overlying koduritC; which at some time or other has been 
subjected to the action of waters that brought silica in solution and 
removed, in some places completely, all the original constituents of the 
rock. 
The ore itself is psilomelane, very seldom free from felspathic or 
limonitic patches. It is either nodular, cellular, or botryoidal in 
shape. About 20 tons of ore had been collected, and a sample of this 
was analysed by Messrs. J. and H. S. Pattinson with the following 
result : — 
Sample No. A. 19. 
Manganese peroxide . . . . . .41-65 
Manganese protoxide ...... 2-72 
Ferric oxide ....... 28-14 
Baryta 0-05 
Silica (combined) 6-75 
Silica (free) 3-50 
Phosphoric oxide ....... 1 -635 
Arsenic oxide . ....... 0-050 
Water (combined) ....... 6-50 
Moisture at 100° C 2-55 
This is equivalent to : — 
Manganese ........ 28-44 
Iron 19-70 
Silica . 10-25 
Phosphorus 0-712 
It will be seen from the above that the ore is quite unmarketable 
further, considering its origin, it is not probable that the ore con- 
tinues to any great depth, while the thickness of the ore-layer is 3^ feet 
