1919.| The Sixth Indian Science Congress. elxxxix 
In addition, various occurrences of auriferous quartz lodes 
aéia’ ve been located, of which perhaps 
the most noteworthy i is — of Kundra- 
kocha close to the southern boundary of the gra 
erhaps, I should mention that the ankriny of all these 
mineral deposits is to occur in impregnated zones, lenticular 
veins and lenses pose itek to the lamination of the enclosing 
phyllites and schist 
In considering oh spatigigialatc: of these various ore-deposits 
a possible index to their source, we 
au to granite probably’ are  eAoatenasee with the presence of 
1 pg var y ather than 
Dahna two sets of igneous intrusives, viz. the 
ranites and granophyres, and the 
basic aoe constituting the Dalma Trap and the numer- 
ous dykes traversing both the Singhbhum granite and the 
Dharwar schists. At first sight it might seem that either 
of these sets of intrusives might equally well be regarded 
as the source of the mineral-bearing solutions. But, in view of 
our knowledge of such rocks elsewhere, we are compelled to 
attribute the pegmatites and the wolfram-quartz deposit to the 
acid magma, and the close association of the copper deposits 
and the magnetite-apatite-rocks with the Dharwar-granite 
boundary leaves little doubt that these minerals, as well as the 
associated uranium, must also have emanated from the granite. 
This leaves Pane! the argentiferous lead deposits and the gold 
deposits. will be seen from the account given above of the 
general ae of deposition in a typical case, we might expect 
lead, gold and silver to be deposited at a greater distance 
nearer to the Dalma Trap, so that the proximity of 
pera Ole cma a Dhadka to the Dalma Trap may have 
no genetic significan 
The suriferous veins of Singhbhum are widely distributed 
and seem to favo r by their sy wage et neither the acid nor 
i ew of the fact that i is 
Poararrars associated with ne gold, and the fact aves 8 vi- 
sions, W 
5 Fs a considered, we are brought to the oe 
that the deposition of the gold in the veins resulted fro 
1 Rec., G.S.I., XXXVIIL, p. 36 (1909) ; and XLIL, p. 75 (1912). 
2 Records, Geol. Surv. Ind., XX XI, p. 81 (1904). 
