1140 MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [ PaRT IV : 
whilst the two peaks are due to lateritoid cappings of mixed manganese- 
and iron-ores. The outcrops of these ores have the usual lichen-covered 
laterite-like aspect. The numerous v/orkings in these two peaks indicate 
that there is a small thickness, 5-10 feet, of the lateritoid mixture of 
ores passing downwards into elates and quartzites, through a zone in 
which these two rocks are parily replaced by the ores. The slates (or 
phyllites) are now mostly represented by white soft clayey rocks retain- 
ing signs of slaty structure ; but in some cases the slates are fresh, then 
being grey to silvery grey in colour. The quartzites are white fine- 
grained, saccharoidal rocks. The replacement of these rocks by 
manganese- and iron-ores is very irregular ; in general a network of ores 
isolates patches of partly replaced or comparatively fresh rock ; 
but in places the ores expand into pockety masses of considerable 
size. 
The strike of the rocks as shown in these sections seems to be that of 
the ridge, namely NN.W., with a variable dip, usually fairly steep, 
to the east side. In two sections in the southern and more important 
of the two peaks thicknesses of replaced beds of 13 and 12 paces, 
respectively, are seen, and the thickness of the replaced rock does not 
seem to be anywhere 'greater than this. 
From the way in which the lateritoid outcrop passes downwards into 
the mixture of slate, quarrzite, and ores, it does not seem likely to 
me that this deposit will be found workable at a profit to a greater depth 
than about 50 feet ; but it is probable that the replacement ex- 
tends inwards for a greater distance than this, though in a very ir- 
regular manner. In the cuttings in the path on the way down 
the hill there are several sections showing bluish grey limestones and 
dolomites. These are seen under the microscope to contain an 
abundance of minute black specks that tend to show squarish though 
blurred outlines. Chemical tests show the rock to be somewhat 
manganiferous, so that it is probable that these specks are, at least 
partly, manganese oxide. It is not possible to say if they are original 
or secondary introductions. If the former be the case then they may 
be the source from which the manganese oxides replacing the rocks 
at the surface to form the manganese-ore deposit were derived. If 
the second be the case, then the manganese may have been introduced 
at the time ot formation of the manganese- and iron-ores on the top 
of the hill above. 
