SYNOPSIS OP PART n. 
Ixxix 
weathering may have extended in the past depends on the level of 
ground water in past times. The conclusion arrived at is that 
the alteration of the rocks of the kodurite series with formation of 
oxidized ores may be guessed as having extended to a maximum depth 
of 500 feet. 
[CHAPTER XVI.] 
The Mang-aniferous Rocks of the Dharwar Facies, including the 
Gondite Series. 
Towards the end of the Archaean era there seems to have been a 
time during which a vast succession of sediments — clays, sandstones, 
limestones, etc., — was deposited, accompanied by the extrusion of basic 
lava flows. These rocks have been smce subjected to metamorphism as 
the result of tectonic movements, with the production of slates, phyllites, 
mica-schists, quartzites, crystalline limestones, complex gneisses, and 
hornblende-schists, the degree of metamorphism being different in 
different areas. At different times the following names have been 
proposed for the rocks of the different areas : — 
Name cf series. 
Year. 
Locality; 
Cham pane r .... 
1869 
Gujarat. 
Aravalli .... 
1877 
Raj pu tana. 
ChilpiGhat . . . . 
1885 
Central Provinces. 
Dbarwar .... 
1886 
Dharwar, Bellary, and Mysore. 
Since it is almost certam that these different series are roughly 
contemporaneous it is desirable to use one name for the whole of them. 
For this purp( se Dharwar is chosen because it is the best kiiown ; and 
it is to be noted that the Dharwars of India are probably equivalent 
to the Huronians of America. Where the Dharwars have been subjected 
to more severe metamorphism than usual they have been rendered 
so crystalline that they can be separated from the remainder of the 
crystalhne complex with difficulty only, and in the Nagpur-Balaghat 
portion of the Central Provinces are referred to as a portion of the 
metamorphic and crystalline complex. 
It is supposed that during the deposition of the Dharwar sediments 
manganese oxides were sometimes deposited chemically from solution. 
7 
