680 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [PaRT IV : 
been interpreted as well as possible and as a result it will be seen that 
while cross-cuts Nos. 3, 3A, and 7, indicate that the western edge of 
the ore ' bed ' is turned up, 4 and (5 indicate that it is turned down and 
presumably goes below the surface to some depth. Roth 3 and 4, how- 
ever, the only two cross-cuts illustrated that show the eastern side of 
the deposit, agree in showing that this edge is turned up and consetjuent- 
ly does not go to the deep. If only half a dozen cross-cuts had been 
made at regular intervals right across the deposit it would have been 
possible to estimate the quantity of ore in it with fair accuracy. Even 
now a rough estimate can be made. From cross-cuts 3 and 4 it is seen 
that a width of some 250 feet of the deposit measured along the folds 
of the ore-band lies within 50 feet of the surface. Taking the average 
thickness of the ore-band as 20 feet, of which 10 feet can be reckoned 
as merchantable ruanganese-ore, the remainder being quartzite and 
poor ore, the length of the deposit as 1,000 yards, the average specific 
gravity of the ore as 4, and assuming that cross cuts 3 and 4 fairly re- 
present the whole deposit, the total quantity of merchantable ore lying 
within 50 feet of the surface can be estimated as : — 
1,000 X 3 X 250 X 10 X 62 5 X4 «o7 non f ti • • 
=: 837,000 tons. llus is 
2240 
probably considerably above the mark ; for it is not likeh^ that 
cross-cuts 3 and 4 do fairly represent the whole deposit. 
The ' coutitry ' consists of silky, silvery, and often crinkled, phyllites 
(sometimes slates or schists), with usually a thick- 
Country . ^^^^ sandy rocks between them and the ore-band. 
These phyllites usually owe their characters to layers of sericitic mica ; 
but as they sometimes contain talc instead of sericite and at other times 
contain both minerals, and it is not possible to tell the character of any 
piece of the rock from merely looking at it, they have all been grouped 
together as sericitoid ^ phyllites. The sandy rocks between these and 
the ore-body are usually of some shade of lavender or lilac, and very 
friable. They have sometimes, where more argillaceous, assumed a 
slaty character, and in one place in cross-cut 3, where they have been 
subjected to intense pressure in some very sharp folds, have been 
converted into sericitoid phyllites, on the cleavage planes of which 
little prisms of piedmontite have developed where the pressure has been 
the most severe (see Plates 18 and 19). 
1 Meaning that the glistening mineral is like sericite, though not always actually 
sericite. 
