460 ADAMS AND PRATT. 



studied by them. Between Isarog and the Pocdol Mountains the forma- 

 tion; consists of basalts, some andesites, and intermediate varieties. 

 Roth and von Drasche called these rocks dolerites. On the map accom- 

 panying this report the tnffs, breccias, and agglomerates are not differen- 

 tiated. 



Sedimentaries are found only in two small areas of this tlivision of the 

 Cordillera. Along the road between Pili and Baao and to the south of 

 the Paiiili River there are some exposures of limestone and marls. This 

 lQQ£|Jity is in the western foothills of Mount Iriga. It was seen by von 

 Drasche, who mapped it as younger coralline limestone. The beds are 

 nearly horizontal and rest upon andesites at some places, but the e)^pos- 

 ures are not good. In our report these limestones are mapped as Ter- 

 tiary. Some small outcrops of a similar nature were seen southeast of 

 Bato, but they are too small to be shown on a reconnaissance map. 



Some coal of poor quality was seen to the east of Mayon, in the barrio 

 of Salvacion which is in the jurisdiction of Libog. It occurs in a rem- 

 nant of the Tertiary formation. These sedimentaries overlie a greenish, 

 altered basalt found in the peninsula east of Libog and which is unlike 

 the typical basalts of Mayon. The Tertiaiy at this place probably is re- 

 lated to the larger area found in the Batan Island chain. 



The western limit of the central division of the cordillera is formed by 

 the ;alluvial and brackish water deposits of the Bicol Valley, except to the 

 sputh where the Tertiary is present on the border. The relation pf the 

 Tertiary sedimentaries to the rocks of this part of the cordillera was not 

 satisfactol-ily determined, but they seem to lie unconformably upon the 

 igneous rocks, and the basal beds contain conglomerates which appear 

 to , have been derived from the cordillera during an early stage of its 

 growth. 



The southern division of the cordillera which includes Bulusan Vol- 

 cano, is formed principally of basalts with which are associated some 

 afl.desites. Roth classified the rocks which he saw from the area as 

 dolerite. A large part is covered with tuffs, breccias, and agglomerates. 

 .I^rpbably much of the tuff is from Bulusan, but no doubt there are other 

 ppfints from which fragmental materials were enipted. There is a fairly 

 distinct range of smaller peaks Avhich lies west of Bulusan and includes 

 Gulungan and Bintican. On the continuation of this line there is an 

 area, of basalts with andesites, north of the entrance to Sorsogon Bay. 

 . No Tertiary sedimentaries were found south of Sorsogon Bay with the 

 ejfcjeption that east of Magallanes there is a bed of coal which has been 

 opened. The roof of the coal has the nature of an agglomerate and, in so 

 far as it was possible to determine, no extensive sedimentary beds are 

 associated with it. The coal is of poor quality, and although it attains 



