IX, A, 3 Edding field: Study of Bulacan Iron Ores 267 



yses show small amounts to be present in most of the ores. Tita- 

 nite and hairlike inclusions in the quartz which are probably 

 rutile are found in the walls, and ilmenite is also present in several 

 of the rocks of the district. 



Chlorite is very abundant. It is almost always associated with 

 magnetite, and is probably of secondary origin. 



Magnetite is found in small quantity in practically all the 

 silicified rock making up the capping of the district and also 

 in the andesite and in the crystallized limestones. It is also 

 found as small veinlets several millimeters wide in the crystallized 

 limestones. 



