44 



HOLLAND: CHARNOCKITE SERIES. 



some intermediate temperature favours the production of garnet, 

 some temperature short of actual fusion but sufficiently high to prevent 

 amphibolization. If this be so, then we may have garnets produced 

 without dynamo-metamorphism, as in some cases they certainly are. 

 At the same time they may also be produced if the rocks are 

 crushed at high temperatures, which maybe high because of the 

 heat produced by the crushing or on account of the depth to which the 

 rock is accidentally buried at the time. In the instance exposed near 

 Pallavaram and illustrated in figs. 4 and 5, the charnockite has 

 been altered probably by the intrusion of the norite, which alone would 

 be sufficient to account for the high temperature accompanying 

 the crushing of the neighbouring charnockite. 



Quartz-felspar rocks associated with charnockite* 



Although, on account of the absence of hypersthene, these 



rocks would not, if found isolated, be recognised as members of the 



charnockite series, yet on account of the facts that they occur as 



veins in normal charnockite and are composed of the same blue 



quartz crowded with minute hair-like inclusions, 



Contemporaneous veins. t0 g et her with a beautifully microperthitic micro- 



cline (fig 3), they must be considered to be as 



Fig. 3.— Microperthitic inclusions in the felspar of No. g' 677. Positions of 

 extinction indicated by crosses. 



( 26 ) 



