Chap. XIV.] dharwar series : secondary ores. 
287 
the manganese-ores occurring in these areas, the following are 
considered to be primary ores : — (1) certainly those situated near 
Localities for the ^^^^ 0^ Chilpi Ghat series in the Balaghat 
primary ores. district of the Central Provinces, (2) probably a 
part of those of Sivarajpur in the Panch Mahals, and (3) possibly 
some of those of the Sandur Hills^ although the available evidence 
is against this. Since the Dharwar rocks have 
Formation of out- , ° i . ji c i 
crop or recent sccon- been exposed at the suriace, other ores nave 
dary ores (lateritoid been formed by the concentration of the usually 
small quantities of manganese contained in some 
of the Dharwar rocks, such as the ferruginous members of the 
series. Such ores can be termed secondary ores ; or as there is another, 
and much more important group of secondary ores, formed in all pro- 
bability in depth in the Central Provinces and Jhabua, and considered 
on page 293, it will be better to refer to those formed on the surface as 
outcrop secondary ores, or alluding to their probable time of formation, 
recent secondary ores, whilst the ones formed in depth can be known as 
the deep or Archcean secondary ores. 
The most important occurrences of outcrop secondary ores are in 
the Sandur Hills and Mysore, practically all the ores of both areas 
in all probability coming under this heading. The source of the 
manganese was probably partly original phyllites and partly ferrugi- 
nous quartzites. Amongst the outcrop secondary ores are those of 
Localities for out- Jabalpur, which have probably been entirely 
crop secondary ores, derived from the small quantities of manganese 
contained in the hematite of the hematitic jaspers by superficial 
alteration and concentration accompanied by the replacement of 
whatever rocks happened to be at the outcrop. Other outcrop 
secondary ores are those of Dharwar, a portion of those of the Panch 
Mahals, in both of which the manganese may ha,ve been concentrated 
from limonitic jaspers ; and a portion, and possibly the whole, of 
those of Goa, North Kanara, and Singhbhum. In the last case the 
immediate source cannot at present be referred to ferruginous rocks 
containing a small quantity of manganese, because such rocks have 
not yet been found in the immediate neighbourhood of the manganese- 
ore deposits. The outcrops of nearly all these ores have a laterite- 
like or lateritoid aspect, and in Belgaum, Goa, and Jabalpur, manga- 
nese-ores are also found in what seems to be true laterite resting on 
rocks of Dharwar age. The distinction between the lateritoid ores 
and those in true laterite seems, however, artificial ; because the field 
