GEOLOGIC RECONNAISSANCE OF SOUTHWESTERN LUZON. 81 



described is the massive limestone in which the gorge is cut. There 

 are no good exposures just to the east of this limestone, the slopes being 

 covered with a heavy talus; but the first rocks in place were found in 

 the river bank are dacites. The contacts in the section just described 

 are not plain. There has been severe dynamic action which has faulted 

 and brecciated some of the beds and all are more or less altered. 



Coal has long been reported from the hills east of the town of San 

 Mateo and to the south of the waterworks gorge. The beds are, how- 

 ever, too thin to warrant exploitation. Eecently some prospecting has 

 been done and the writer has been told that the coal occurs with some 

 arenaceous and argillaceous beds which are associated with the limestone. 



Limestone is found near Angat. Itier, according to a citation by 

 Von Drasche, mentions limestone on the banks of the Angat River, with 

 uplifted vertical strata and inclosing fossils. 



The occurrence of limestones near the springs at JSTorzagaray to the 

 south of Angat was noted briefly by Centeno, as was also an occurrence 

 to the east of San Miguel near the springs of Sibul. The latter locality 

 is just to the north of the area here under discussion. Both of these 

 limestones are probably continuations of those near Angat. 



McCaskey has described more fully the outcrops near Angat. His 

 localities are Mount Pecote, the banks of the Bayabas River between 

 Sampaloc and Bayabas, Bocol Hill to the south of the river and the 

 Baras-Bacal Hills to the north. He states that the conspicuous lime- 

 stones occur as massive beds overlying thin limestones, sandstones and 

 shales. Mount Puning, in the Baras-Bacal Hills, is a conical hill of 

 limestone through which the Santol Creek passes in a cave about 1.5 

 kilometers long. In the shales associated with the limestones McCaskey 

 found inferior thin beds of lignite, one at the barrio Sampaloc in the 

 shales exposed by the Bayabas River, another in upper Sapa Santol, and 

 a third in the Arroyo Laguio Malaqui near Norzagaray. The limestone 

 areas were described by McCaskey but not mapped and are shown ap- 

 proximately on the geologic map accompanying this report. 



Next in order may be mentioned the outcrops along the Mauban-Lucban 

 Eoad on the southeastern part of the map. The occurrence of limestone 

 in this section was suggested by the fact that Jagor and Roth described 

 limestone conglomerates and conglomerates containing limestone pebbles. 

 There is a massive limestone ^exposed in the river and near the road 

 about 9 kilometers west of Mauban. Other outcrops probably occur in 

 the section, since lime is burned from rock obtained to the east of Lucban. 

 The presidente of Sampaloc reported the occurrence of limestone at 

 several places which could not be located on the map because of deficient 

 geographic details. It may be noted here that he described an in- 

 termittent spring near Sampaloc which may prove interesting to anyone 

 having time to study it. There are a number of exposures of shales and 



