144 Journ. of the Asiat. Soc. of Bengal. [May & June, 1915. | 
probably metamorphosed basalts and diabases in the form of 
lava flows, sills, etc., and very possibly some pyroclastic 
accumulations. The upper division is more varied and consists 
largely of rocks characterised by the presence of chlorite—such 
as greenstones and chlorite schists and less commonly mics 
chlorite schists and mica schists. Many of the greenstone 
e 
into chlorite schists. In places the micaceous members 
Apart from the undoubtedly igneous types and_ thes 
doubtful schistose types the system contains a number 
other types, the physical and chemical characters of which 
} a sedimentary origin for many of the ™ 
obscure highly schistose rocks associated with them. ae 
more closely the conglomerates of Mysore are studied, 
the less probable does their sedimentar at 10 
one of the subsequent gneisses or in both. Other cases which 
have not been closely studied may still be open to questi 
but on the whole we are fairly well satisfied that their orig 
ary. . 
e problem of the banded ferruginous quartzites presealt 
much greater difficulty, owing largely to the fact that the | 
contacts with other rocks are very obscure. Owing 0 Oy 
k : 
and generally also obscured by a talus of quart j 
