IX, A, 3 



Dalburg and Pratt: Iron Ores of Bulacan 



209 



ment of older igneous, including both surface and deep-seated 

 types of undetermined age, Miocene sediments were laid down. 

 The base of this series and the rocks upon which it lies are 

 cut by dikes or small intrusions. In the upper part of the series 

 andesites are found which, although fragmental, appear likewise 



T?-^ 



Older rjra velb . I Recenf 



-4J/uiL'UrDL0 -jOrp^ J 



^/7<r/ ^rcfy<s:/s:0 - 300m. SF/eJ^shcene 



-Sha/<? anc/ -^onc/sZ-one SO/JiA or /■>\ 



^h£/e:__ ^00m._ \ M/oce^e 



/^ r7cTe<s}T<2 ; mass/i/e | 



Ond aa^/omeraf/c. \ P//o(ene(? ) 



^/jcdes, <3on c/s-/on e, fa/^.->j 

 and c/ash'c rocAs:o//erna/rn^ 

 ded^: 600 -ZOOOm. 



Miocene 



Limeslone_ ._ _/^ ;S0_ rn._ 



Infras/ves. dikes, silkefc 



I//? d///eren // d/-ed 

 errasive (7/7c/ /nfras/i/e. 



Or on iJ-e. 



Miocene or 

 Ollqoc^ne ^/-^ 



rPre-M/ocene 



Fig. 2. Stratigraphic column for the Bulacan iron-ore region. 



to be intrusive, but are probably later than the intrusions in the 

 basal beds. Overlying the Miocene beds unconformably are 

 bedded tuffs, clays, sands, and gravels which are believed to 

 belong to the Pleistocene, and upon these in turn are recent 

 deposits including older gravels and modern alluvium. 



