322 



The Philippine Journal of Science 



1913 



A final section obtained at the village of Cubcub (outside the 

 area mapped), about 15 kilometers northwest of San Narciso, 

 is shown in Table XII. 



Table XII. — Geologic section on Guinhalinan River in the vicinity of 



Cubcub, Peris. 



Formation. 



Description. 



Approx- 

 imate 

 thickness. 





Upper limestone; coralline; isolated patches only; 



summit of Mount Bogas. 

 Cudiapi sandstone; bedded, calcareous, fossilif- 



erous; toward base, clayey. 



Meters. 

 10 



80 



Canguinsa sandstone 



Gray, sandy clay, massive and fossiliferous. 

 Tinaplaca Creek. 



/Brown coarse-grained sandstone; traces of in- 

 flammable gas. Tinalpaca Creek. 



Thin-bedded shale with occasional sandstone beds; 

 Tinaplaca Creek, Pigsaan Creek and Guinhal- 

 inan River at Cubcub. Extensive exposure at 

 Cubcub; in upper part, sandstone beds 10 centi- 

 meters to 1 meter thick with blue to gray, fine- 

 l grained, thin-bedded shale and brown, sandy 

 shale; farther down in series fewer sandstone 

 beds, more sandy shale in thin beds alternating 

 with shale of finer grain. Strata lie inclined at 

 an angle of 30° and show subordinate buckling in 

 lower part of series; thickness in continuous ex- 

 posure, 250 meters; Indicated additional thick- 



\ ness, 3S0 meters; base not exposed. 



100 

 3 



600+ 







Alluvium and travertine. — Recent alluvium is found along 

 the valleys of Pagsanhan, Vigo, Mulanay, and Ayoni Rivers. 

 It occurs near the mouth of the Pagsanhan, but on the other 

 rivers it is most extensive along the middle courses above the 

 gaps through which these rivers enter the sea. The material 

 consists of clay and sand with subordinate quantities of sand- 

 stone and limestone gravel. Fresh-water shells and occasionally 

 pieces of wood partly carbonized are found in the alluvium. The 

 river terraces usually rise less than 6 meters above the level of 

 the stream. 



Travertine is also deposited by running water throughout 

 Bondoc Peninsula and is of more general distribution than 

 alluvium, although as a geologic formation it is subordinate. 

 The salts of calcium which are deposited as travertine are leached 

 from the limestone and calcareous sandstone strata, usually by 

 surface waters. Deposits from springs are exceptional. As is 



