ILLUSTRATIONS. 



Plate I. 



Sketch showing the geologic mapping of southeastern Luzon, by von Drasche. 



Plate II. 



Mayon Volcano, photographed from a distance of fifteen kilometers from its 

 summit. Legaspi in the foreground. 



Plate III. 



Part of the crater rim of Mayon. (Photograph by Martin.) 



Plate IV. 



Fig. 1. Portion of inner wall of the crater of Mayon. (Photograph by Martin.) 

 2. Looking up a gulch near the summit of Mayon. (Photograph by Brown.) 



Plate V. 



Fig. 1. Slope of Mayon showing lava beds. (Photograph by Brown.) 



2. Slope of Mayon showing detrital material. (Photograph by Martin.) 



Plate VI. 



Fig. 1. Pool of hot water with silicious sinter border. Tiui Hot Spring-s. (Pho- 

 tograph by Alga.) 

 2. Silicious terraces and pile of foreign materials with silicious cutting. 

 Tiui Hot Springs. ( Photograph bj' Alga. ) 



MAP. 



Geologic reconnaissance map of southeastern Luzon. 



TEXT FIGURES. 



Fig. 1. Index map showing physiographic regions of Luzon. 



2. Physiographic divisions of Southeastern Luzon. 



3. Sketch showing the lines of descent of volcanic materials from the slope 



of Mayon during the eruption of 1897. Taken from a map by Coronas. 



4. Sketch showing the approximate area in which ashes fell during the 



eruption of Mayon in 1897. Taken from a map by Coronas. 



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