Plate XIII. 



Dyke of Charnockite series in Biotite-Gneiss. 



In the eastern part of Coorg the charnockite series, besides forming large 

 masses, occur as dykes which are generally garnetiferous. They cut through 

 biotite-gneiss approximately parallel to the foliation strike in a N.W.— S.E. 

 direction, and are often themselves slightly foliated. The rocks which form these 

 dykes are composed of the minerals which characterise the intermediate and basic 

 members of the charnockite series, and are granulitic in structure though com- 

 paratively fine-grained. The selvages of the dykes are more compact, more basic 

 and more hornblendic than their central portions. 



