260 The Philipinne Journal of Science 1915 



upturned edges of the Vigo shale. A pit about 2 meters deep was 

 dug at J, and enough petroleum was encountered to make possible 

 the collection of a 1-liter sample. Gas escaped from the floor 

 of the pit with a slight rushing sound and moved small pieces 

 of debris around which it flowed. The shale in the pit walls 

 is dark in color and is impregnated with petroleum, although 

 the flow of petroleum came from bedding planes and joints. 

 Dark gray sandstone occurs in the shale, but while it has a 

 strong petroliferous odor, it is not impregnated with petroleum. 

 About 500 meters to the east of the seepage at J the Canguinsa 

 rocks are encountered overlying the Vigo, but directly south 

 of the seep the Vigo is exposed over a greater distance. The 

 seepages at both I and J, therefore, come from beds which are 

 well below the top of the Vigo shale. If the igneous rock at 

 I is not intrusive, then the one seepage must be in the very 

 base of the Vigo. 



The petroleum at J is very fluid and has an odor of light 

 oils. It is olive-green by reflected light and reddish brown by 

 transmitted light. The results of fractional distillation appear 

 in Table V under the discussion of the character of the petro- 

 leum and bitumens. Apparently the petroleum at H and I is 

 of the same character as that at J. 



At the point marked K there is a small outcrop of semisolid, 

 black bitumen filling a pocket in loose limestone and clay. There 

 are no good outcrops in the immediate vicinity, but it is prob- 

 able that Vigo shale is the underlying rock. The outcrop is 

 too small to afford any idea of the character of the bitumen 

 or of the manner of its occurrence. 



At L and M, near the towTi of Villaba, there is an apparently 

 extensive deposit of solid bitumen mixed with fragments of 

 Canguinsa clay-tuff. This material is encountered just beneath 

 the surface and has been opened by shallow pits at two places 

 about 300 meters apart. About 100 tons of the mixture have 

 been mined from these openings, one of which reached a depth 

 of 5 meters continuously in the bituminous material. The bitu- 

 men in this deposit is like that in the region of the E, F, and G 

 outcrops in character, but within a few meters of the openings 

 there are also domes or chimneys of brecciated, hardened clay- 

 tuff cemented with viscous bitumen like the material in the out- 

 crops at D. Outcrops L and M appear to be in the upper part 

 of the Canguinsa clay-tuff, which in this vicinity dips at low 

 angles to the south. 



At the point marked N on the map in fig. 2 is the deposit of 

 bituminous limestone already mentioned. At this place porous 



