ILLUSTRATIONS 



Plate I 



, (Photographs by Pratt) 



Fig. 1. Binangonan limestone in Mount Bahay Panique (home of the bats) ; 

 looking southwest. 



2. Typically forest-covered slope in iron-ore region; Mount Mayapo. 



3. Balubad Falls over a face of bedded tuff; Balaong River. 



Plate II 



(Photographs by Charles Martin) 



Fig. 1. Granular magnetite in fibrous amphibole (tremolite?), hanging 

 wall Constancia ore body; natural size. 

 2. Specimen across wall of magnetite vein in limestone, Camaching; 

 natural size. 



Plate III 



(Photographs by Pratt) 



Fig. 1. Magnetite vei'n in limestone, Camaching. 



2. Inclusions of limestone in iron ore, Camaching. 



3. Small diabase (?) dike in diorite, Bayabas River; quartz filling 



along fractures. 



Plate IV 



(Photographs by Pratt) 



Fig. 1. Ore pit at Hison ore body. 



2. Ore face in pit at Montamorong. 



3. Large hematite bowlder in stream below ore body, Santa Inez. 



Plate V 



(Photographs by Pratt) 



Fig. 1. Filipino blast furnace in operation, Mayapo. 



2. Cast-iron plowshare and plowpoint produced by Filipinos in Bulacan. 



3. Iron smelter in forest, Camaching. 



Plate VI 



(Photographs by Pratt) 



Fig. 1. Charcoal burning; wood in place in kiln. 

 2. Charcoal burning; kiln at end of firing. 



MAP 



Geologic map of Bulacan iron-ore region. 



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