1919. The Sixth Indian Science Congress. elxxxiii 
increase in phosphorus should cease once the ground water- 
level (past as well as present) has been reached. 
B. Syngenetic igneous ore-deposits. 
Chromite Deposits. 
ale e, ar Savantvadi, the other chief group of 
deposits (those of Baluchistan) occurring in saxonites of cre- 
taceo ese, I have been enabled personally to study 
conve by shearing into talc-schist ore-bodies are 
usually in the form of bands, which, according to the evidence, 
are primary segregations drawn ne case 0 
serpentine, was also found. 
Further to the east, in Dhalbhum, where the Dharwars 
have suffered much. more intense metamorphism than near 
modified by more intense metamorphism. 
The possible chemical equations representing | the forma- 
tion of serpentine from olivine have been recently investigated 
by R. P. W. Graham,! in connection with the Quebec occur- 
to iron-bearin ntine by simple hydration and oxidation 
without gain or loss of silica or magnesia, e.g. for Mg: Fe 
=1:1;— 
But with Mg : Fe = >3: 1, the conversion of olivine into ser- 
pentine must be accompanied either by addition of silica or by 
1 Econ. Geol., Vol. XII. pp. 162-170 (1907). 
