ILLUSTRATIONS 



Plate I 



Panorama from Mount Amuyao to the southwest. (Photograph by Smith.) 



Plate II 



Fig. 1. Malaya Range across Abra Valley from near Cervantes. (Photo- 

 graph by Martin.) 

 2. Abra River between Tinglayan and Lubuagan. (Photograph by 

 Smith.) 



Plate III 



Fig. 1. Rice terraces at Lubuagan ; three crops are obtained each year here. 

 (Photograph by Smith.) 

 2. Topography in the region of extrusive rocks; looking southeast 

 from near Tadian. In the middle distance is an old volcanic 

 plug. (Photograph by Smith.) 



Plate IV 



Fig. 1. Limestone at Sagada. (Photograph by Smith.) 



2. Nearer view of Sagada limestone, showing weathered forms. (Pho- 

 tograph by Martin.) 



Plate V 



Fig. 1. Shale beds in trail to Lubuagan. (Photograph by Smith.) 

 2. Terraces at Salinas salt spring. (Photograph by Martin.) 



TEXT figures 



Fig. 1. Outline map of northern Luzon, showing region traversed. 



2. Generalized geologic section across northern Luzon, from Tagudin 



to the eastern coast. 



3. Sketch of the vicinity of Bontoc. 



4. Sketch showing slide near Sagada. 



5. Profile of box canon at kilometer 6, south of Bontoc. 



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