Plate XV. 



Relations of Charnockite to Garnetiferous Leptynite* 



In the small hill range east of the railway station of Pallavaram, n miles south 

 of Madras, we have an example of the passage of ordinary charnockite into garnet- 

 iferous leptynite near its junction with the basic form, norite. The norite passes 

 as a narrow band through the charnockite mass, and the junctions on either side 

 are marked by ridges of the garnetiferous rock which is also slightly pyritous. 

 The mutual relations of these rocks in another precisely similar instance occurring 

 about a mile further east of the railway station are described on pp. 173 and 174. 

 The garnetiferous leptynite is described on p. 142. 



