viii, a, 5 Pratt and Smith: Petroleum Resources 349 



sandstone appear to have been formed as a continuous deposition 

 in deep or quiet water. Parts of the formation, however, are 

 coarse grained and were probably laid down in shallow seas 

 similar to those which must have prevailed during the deposition 

 of the Malumbang series. The growth of coral in the limestones 

 in the Malumbang series indicates that the water was clear at 

 times toward the end of sedimentation. 



The Pleistocene and Recent deposits of volcanic tuff, which 

 are extensive in the neighboring territory of southwestern Luzon, 

 do not reach as far to the southeast as Bondoc Peninsula. Sub- 

 sequent to the Pliocene, apparently, the mass of Bondoc Pen- 

 insula has been above sea level, and subject to erosion which 

 has been very extensive and has removed great thicknesses of 

 strata. 



OCCURRENCE OF THE PETROLEUM 



The petroleum on Bondoc Peninsula appears as seepage from 

 the floors or sides of streams. At some places the oil rises 

 spontaneously and floats away on the surface of the water. 

 More commonly it appears only after the prospector has dis- 

 turbed the rocks at the bottom of the stream. Digging in the 

 shale of the Bacau stage where it has been freshly exposed by 

 stream erosion generally yields small quantities of petroleum. 

 The oil is invariably accompanied by inflammable gas, and in 

 a number of instances inflammable gas is encountered in the 

 absence of oil. At none of the seeps is there evidence of a large 

 flow of oil at the surface. To collect as much as a liter of oil 

 from any of the seeps involves a considerable amount of work 

 in turning over the rocks and stirring up the mud in the streams 

 along which the oil is found. The petroleum contains a large 

 proportion of volatile constituents, and all trace of oil is lost 

 soon after it appears on the surface. There is no discoloration 

 of the ground around the seeps, but a scum gathers on the water 

 and on stones or sticks in the water for a short distance down- 

 stream from an oil seep. The proximity of a seep is usually 

 manifested first by the odor of kerosene which is evolved rather 

 than by visible evidence of the petroleum. 



In all cases where oil has been found, it occurs in or near 

 the Bacau stage of the Vigo shale, more or less closely below 

 the Canguinsa sandstone in the stratigraphic column. The seep 

 on Malipa Creek, near Cabongahan, is at the lowest horizon in 

 the Vigo shale at which oil has been encountered. Here Vigo 

 shale some 250 meters thick intervenes between the oil seep and 



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