CiiAr. XXXVI.] 
NAGPFR : KANDKI. 
867 
the shape of this sheet shown in figure 55 is roughly the original shape 
of the basin in which the sediments were deposited, or that this supposed 
shape has been produced by earth movements pinching this piece off 
from the remainder of the ore-layer. This sheet has been spoken of 
above as an ore-body, but it is of course not known how much of the 
sheet is manganese-silicate-rock and how much is merchantable man- 
ganese-ore. 
A very interesting feature of this deposit is the fact that almost 
. everywhere both the manganese-ores and the accom- 
Slickensides-gi-oovins. . ° , , , , 
panying granuhtic gneiss show a well marked parallel 
grooving. This is no doubt of the nature of slickensides, but real polished 
slickensides are rare and have been found only on loose pieces of 
manganese-ore in the talus-deposits. The grooves are sometimes as 
much as 4 inches deep, the sides of these grooves being then often 
scored by smaller grooves. The average direction of this grooving is 
about E. 30° S. at 30°, but it varies somewhat in different parts 
of the deposit. Thus in the North and East Hills it tends to point more 
to the south-east at a somewhat steeper angle, whilst in South Hill it 
is almost constantly to E. 25° S. at 25° to 30°, usually 28°. In South 
Hill, the sUckensides-grooving points right down the ore-deposit, giving 
the manganese-ore body a columnar structure, and this, together with 
the cross -jointing, greatly facilitates the extraction of the ore. Plate 
30 shows well the shckensiding in level 2. If we regard the 
mica-schists and included ore-body as an ' eye ' in the gneisseSj then 
we can suppose that these groovings, which roughly conform to the 
length of the eye, were formed by the same earth movements as formed 
the eye. 
One piece of manganese-ore was found with attached white material, 
, . , ,. , which under the microscope was found to be a rock 
An interesting rock. -'^ . 
composed of practically colourless garnet in a matrix 
of untwinned (probably orthoclase) felspar. The garnet is probably 
a pale variety of spessartite and has been largely replaced by manganese- 
ore. The rock is of interest as being probably an orthoclase-spessartite- 
rock and thus a felspathic member of the gondite series. 
In the portion of South Hill lying between the south-east end and the 
Nature and quality Summit A, the manganese-ore is, as far as exposed , 
of the ores. of uniformly good quality for the whole width 
of the band. It is a fine-grained crystalline ore varying from very 
hard to soft and composed apparently of braunite with a certain pro- 
IV s 
