308 The Philippine Journal of Science wis 



the axis trends north-northwest and south-southeast. Pusgo 

 Bay, lying between San Narciso Peninsula and the mainland, 

 is the largest coastal indentation. San Narciso Peninsula is 

 remarkably similar in form and contour to the larger parent 

 mass. 



OROGRAPHY 



The surface of Bondoc Peninsula rises from the seashore on 

 both sides to a generally high, but dissected, interior. Before 

 erosion became effective, the peninsula must have had a flattened, 

 arch-like cross section. Through erosion, however, a great deal 

 of the material of the former arch has been removed, the relative 

 proportion which remains varying locally. In the northern 

 part of the field, but little of the old surface is left — a ridge of 

 tilted beds dipping toward the sea along the lateral coasts rep- 

 resents the lower part of the sides of the arch, while the highest 

 elevations, farther inland, lie just below the former surface of 

 the crown portion. Farther south erosion is not so far advanced 

 and the larger part of the crown remains as a high interior 

 plateau, incised by deep canons. 



From San Narciso south along the eastern coast the coastal 

 ridge continues unbroken to the mouth of Vigo River, which cuts 

 through it between the peaks of Cambagaco (elevation, 300 

 meters) on the north and Dagmit (elevation, 350 meters) on 

 the south. South of Mount Dagmit, the ridge is continuous to 

 Bahay River, which like the Vigo empties into the sea through 

 a narrow steep-walled valley. South of Bahay River the crest 

 of the ridge is broken by the valleys of several small streams 

 which flow across it, and the elevation decreases ; although Mount 

 Maglihi, one of the southernmost peaks, is 390 meters high and 

 is mountainous in aspect. 



On the western coast, the marginal hills are lower (elevation, 

 from 100 to 200 meters), the chain contains no conspicuous 

 peaks, and the ridge is generally less prominent than the eastern 

 coastal ridge. 



In the central portion of the peninsula, the dissected plateau 

 is formed by Cudiapi Range (highest elevation, 443 meters) on 

 the north, with Balinsog Hill (elevation, 394 meters), Malum- 

 bang Plain (elevation, 250 to 270 meters), Mount Malasimbahan 

 (elevation, 360 meters), Mount Anuing (elevation, 350 meters), 

 Mount Banaba (elevation, 355 meters), and their environs mak- 

 ing up the southeastern portion. South of Cudiapi Range and 

 west of Mount Banaba, the high tableland persists across Pina- 

 malijuan Plain to the vicinity of Tala and Sili. On the north 

 this interior plateau drops abruptly to the low-lying valleys of 



