250 The Philippine Journal of Scierice isis 



Tayabas. They form smooth white faces, which are numerous 

 along the western coast. They are encountered both above and 

 below the calcareous sandstone, while the coralline limestones 

 are usually above the sandstone. The chalky limestone appears 

 to contain very fine tuff in some exposures. 



South of Villaba and east of Baliti the Malumbang series has 

 been impregnated with bitumen. The bituminous limestone 

 and bituminous sandstone so formed outcrop at the head of a 

 caiion near the summit of the hills. It is probable that the 

 cafion marks a fault, since Vigo shale is exposed in the wall 

 opposite the bitumen-impregnated face. Here the Malumbang 

 series is at least 50 meters thick and is clearly conformable 

 over the Canguinsa, both formations dipping at low angles to the 

 south. The lower beds are calcareous sandstone (lower lime- 

 stone missing) , while the upper part of the series is fragmental, 

 coralline limestone. Elsewhere in Leyte, especially on the 

 northern part of the peninsula, the Malumbang series is much 

 thicker and may attain a maximum of 200 meters. 



In distribution the Malumbang may be said to be confined to 

 the tops of the hills along the coast in the southern part of the 

 region, extending inland farther north until it is intact across 

 the north end of the peninsula. It is especially heavy on the 

 northeastern coast of the peninsula. 



CANGUINSA CLAY-TUFF 



The Canguinsa as it occurs in Tayabas is a light gray, light 

 brown, or light blue, massive clay-tuff, or clayey tuff -sandstone, 

 both of which, although soft, are dense and tough as a result 

 of their close, fine-grained texture. The rock is imperfectly 

 bedded at places ; elsewhere it is massive. It is usually slightly 

 calcareous and contains numerous small fossils (Table I). It 

 breaks with a subconchoidal fracture and weathers into frag- 

 ments with concave faces, which are smooth and greasy to the 

 touch and emit a faint odor of bitumen. At places toward its 

 base the Canguinsa becomes fissile and takes on something of 

 the character of the Vigo shale. 



This description applies perfectly to the Canguinsa in Leyte, 

 where it is in every respect similar to the Tayabas occurrences. 

 A fact which escaped mention in the report on the Tayabas field, 

 however, is that the Canguinsa contains a large proportion of 

 volcanic tuff of varying fineness. In places it is a clay-tuff; at 

 other places, a tuff-sandstone. The individual grains of tuff are 

 sharp fragments of glass, calcic feldspar, and subordinate 

 quartz. 



