356 The Philippine Journal of Science 1913 



Table XIV. — Composition of the gas from a gas seep on Malipa Creek. 



Per cent by 

 Constituent. volume. 



Hydrogen 0.7 



Methane 62.3 



Ethane 0.3 



Carbon dioxide 2.3 



Nitrogen 25.5 



Oxygen 7.2 



Carbon monoxide 2.0 



It will be noted that the gas contains an unusually large per- 

 centage of oxygen. Some of the oxygen may be due to contam- 

 ination of the sample by air, although care was exercised to 

 prevent contamination. Not all the oxygen can be due to the ad- 

 mixture of air, however, because the gas does not contain the 

 corresponding proportion of nitrogen. It is probable, therefore, 

 that the oxygen is an original constituent of the gas. 



Mr. E. J. Cooke, in 1906, drilled a well on the west bank of 

 Malipa Creek about 50 meters upstream from the gas vent. This 

 well is said to have reached a depth of 21 meters and to have 

 encountered a small quantity of oil. The top of the well is at 

 an elevation of 20 meters. 



PETROLEUM ON TANGOB CREEK 



Inflammable gas and traces of petroleum can be obtained on 

 the upper part of Tangob Creek by moving the stones and debris 

 which cover the Vigo shale in the bed of the creek. In this 

 vicinity Tangob Creek flows between Cambagaco Kidge on 

 the east and a hill of volcanic agglomerate on the west. The 

 outcrop of agglomerate is surrounded by Vigo shale, and the 

 gas and oil are encountered within a few meters of the igneous 

 rock. In the base of Cambagaco Ridge, Canguinsa sandstone 

 occurs, overlying the shale and dipping to the east-northeast 

 at an angle of about 20°. The lower part of the Canguinsa is 

 rich in fossils where Tangob Creek flows across it. The shale 

 at the point where the oil was observed is blue to black, and occurs 

 in thin beds dipping east-northeast at an angle of 65°. The 

 dip and strike of the shale are not constant, however, but vary 

 greatly in this region. The petroleum seep is about in line with 

 the axis of the Bato anticline, but the strata in which it occurs 

 are part of the confused structure in the eastern limb of the 

 Central anticline north of the Cabongahan. 



PETROLEUM AT BATO 



Petroleum has been found on the little creek just east of Bato 

 in the shale forming the western limb of the acute fold described 



