X. A. 4 Pratt: Petroleum and Residual Bitumens 243 



bitumen and fragments of clay-tuff has been discovered in the 

 edge of the town of Villaba itself. This deposit appears to be 

 of considerable extent laterally. To the south of Villaba at a 

 distance of about 3 kilometers there is a large outcrop of 

 bitumen-impregnated limestone, and east of this occurrence there 

 is another small outcrop of solid or semisolid bitumen. Finally, 

 viscous black bitumen has been found just inland from the barrio 

 of Tabubunga, 10 kilometers south of Villaba. Both petroleum 

 and solid bitumen are reported from other places in northwestern 

 Leyte, but these reports were not verified. Some of them appear 

 upon examination to be unreliable, but in view of the geology of 

 the region it will be surprising if other occurrences of petroleum 

 and bitumens derived from petroleum are not discovered. 



The principal known occurrences of petroleum and related 

 bitumens, therefore, are distributed over an area 8 kilometers 

 wide and 13 kilometers long. The peninsular portion of north- 

 western Leyte as far south as the barrio of Baliti is a geologic 

 unit and should be included in the area which may contain 

 petroleum, although surface indications of petroleum will prob- 

 ably not be encountered in the northern part of the peninsula, 

 because there erosion has not removed the cover of rocks over- 

 lying the petroleum-bearing formation as it has farther south. 



The vicinity of Villaba is shown on the accompanying map, 

 fig. 2, together with all of the known bitumen outcrops and 

 petroleum seepages. In fig. 1 northwestern Leyte is shown in 

 outline. Both these maps are based on Coast and Geodetic 

 Survey charts. The situations of the outcrops as shown on the 

 detailed map were obtained by compass surveys. 



PHYSIOGRAPHY 



Northwestern Leyte is of only moderate relief^ — rarely do the 

 elevations exceed 350 meters — but the valleys are deeply incised, 

 and the slopes are usually steep. The topography reflects 

 strongly the geologic structure — nearly flat-topped ridges and 

 hills in the extreme north where the strata are level or only 

 slightly inclined, and sharp points and knife-edged divides in 

 the steeply dipping shales farther south. A resistant limestone 

 near the top of the rock series withstands erosion, so that in 

 places it becomes a base upon which remain little groups or 

 rows of regular conical hills carved out of the softer overlying 

 sandstone. 



The rainfall is carried off by a number of small drainage 

 systems, so that within the petroleum region there are no large 

 streams. The headwaters of the river which reaches the sea 



