Chap. XV.] 
GONDITE SERIES : OKIGrN". 
309 
Provinces I the opinion was expressed, it is true with, considerable 
diffidence, that the manganese-bearing rocks of this area were intruded 
in the molten condition into the metamorphic schists, gneisses (and 
quartzites), with which the manganese-silicate-rocks are associated. This 
was written because it was then supposed that the manganese-garnets 
of Vizagapatam and the Central Provinces were the same and because 
in both areas the manganese-ores, at least in part, have been formed 
by the chemical alteration of the rocks containing these garnets. It 
was not then thought Ukely that there could be in one country, large 
though India is, two distinct series of rocks, each characterized by the pre- 
sence of manganese-bearing garnets. The evidence derived from the 
study of the Vizagapatam occurrences in the field as exposed in the mines 
was so unequivocal in pointing to their igneous origin, that it was attempt- 
ed to make the origin of the manganese-bearing rocks of the Central Pro- 
vinces, which then seemed much more open to opinion agree with that 
of the manganese-bearing rocks of Vizagapatam. Since then, however, 
I have been able to make a much more careful microscopic examination 
of the Central Provinces rocks with the resultant abandonment of the 
igneous theory and a return to the theory that had first suggested 
itself in the field, namely that the manganese-silicate-rocks of the Central 
Provinces are metamorphosed sediments^. 
Since it has been found possible to ascribe an igneous origin to these 
• , f rocks, even doubtfully, it will be as well to put for- 
P.vidence lor igneous ' _ •' ' tr 
oritrin of the gondite ward here what evidence there is for that theory. 
In the first place, as the result of a careful piece of 
mapping at Ramdongri in the Nagpur district, it was found that the mass 
of manganese-silicate-rock forming hill No. 5 forked at its eastern end. 
(See the map of this area, Plate 24.) Moreover, the thin band of rho- 
doniferous rock running east from the bank of the Kanhan river strikes 
straight towards the main mass of this hill and apparently disappears 
just before reaching it. This may be due either to faulting or to a sudden 
thinning out of the band. Assuming, in either case, that this thin band 
corresponds to the huge lenticular swelling (as seen in plan) forming the 
main mass of hill No. 5, it was thought that this sudden change in the 
width of the manganiferous band could be easily explained on the hy- 
1 Rec. G. S. 1; XXXIII. p. 97, (1906); and Trans. M!n. Oeol. Inst. Jnd., I, p. 91, 
{190()). 
2 This change of views has already been put forward in the discussion on my paper 
•Manganese in India' in the Trans. Min. Geol. Inst. Ind. I, pp. 228-231, (1907), and in 
Rec. O. 8. I., XXXV., p. 39, (1907). 
