1686 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [ PaRT IV : 
still remain,'\but are kaolinized and separated by a black network of 
manganese oxide. Outside the black border the rock is quite unblack- 
ened. With the advent of further supplies of manganiferous solutions to 
this patch this outer border would gradually increase inwards in thickness, 
leaving a smaller and smaller central core of kaolinized rock, imtil the whole 
patch had been converted into ore (probably pyrolusite, but possibly psilo- 
melane). On the opposite side of the same cutting as that illustrated in 
Fig. 2, Plate 54. and only 10 paces further a^ong the strike {i.e., towards 
the observer as one looks at the plate), the comparatively large area 
of white rock illustrated in Plate 54 is reduced to that shewn in Figure 86, 
in which kaoUnized felspar-rock, with the felspar grains in an ochreous 
matrix, is surrounded on both sides by rock, composed of yellow ochre 
containing streaks and spots of soft black ore, the whole maintaining 
Fig. 86.— Felspar-rock undergoiag replacemeut by mangancscore and ochre. 
the general southerly dip. The junction between the two rocks is as 
before marked by a 1-inch zone of soft black manganese-ore. 
