RECONNAISSANCE OF SOUTHEASTERN LUZON. 451 



were published in a press bulletin are incorporated in this paper. Cara- 

 muan Peninsula and most of the northern part of the cordillera, including 

 Mounts Labo and Cadig, are practically uninhabited and very little is 

 known of their interior geography. Only meager information was gained 

 concerning the geologic constitution. 



The new, accurate charts by the Coast and Geodetic Survey show many 

 modifications of the position and details of the coast as given on the old 

 maps. The geography of the interior is best known from the unpublished 

 maps by d'Almonte, which in places are only sketches. 



The economic geology of the area centers in the coal mines on Batan 

 Island, which have been studied by Smith, the Paracale-Mambulao min- 

 ing district, which is producing and has been the subject of several short 

 reports, the Nalasvetan mining camp which is new, the prospects on the 

 head of Ragay Gulf, and the Tayabas oil fields, where drilling is now in 

 progTess. On Catanduanes Island prospecting for gold is being carried 

 on and coal has also been found. Coal is likewise known to exist on 

 Rapu-Eapu Island and at a number of places on the mainland, but it is 

 not now being mined, except on Batan Island. 



PHYSIOGRAPHY. 



The dominant physiographic feature of southeastern Luzon js a chain 

 of volcanic peaks extending in a northwest-southeast direction and hei'c 

 named the Southeastern Cordillera.^ (See figs. 1 and 2). 



Caramuan Peninsula, and Catanduanes Island which seems to be 

 related to this peninsula, form a province which diverges from the central 

 portion of the cordillera. Farther south the Batan chain of small 

 islands, including San Mig-uel, Cacraray, Batan, and Eapu-Eapu Islands, 

 lies nearly parallel to the cordillera. The Eagay Coast Hills are on the 

 western flank of the chain of volcanic peaks. The northern and southern 

 parts of this province border the Southeastern Cordillera, but its central 

 portion is separated from the latter by the Bicol Valley. Bondoc Penin- 

 sula, or Tayabas Peninsula as it is sometimes called, and the isthmian 

 portions of Luzon to the north of it, are a continuation of the Eastern 

 Cordillera. 



Alabat Island is related to this region. Between the Eastern and 

 Southeastern Cordilleras and extending from Ragay Gulf to Basiad nnd 

 Calaxiag Bays, there is an area of slight relief which is here called the 



^ On the index map of the physiographic regions accompanying the report on 

 southwestern Luzon {loc. cit.) the Southeastern Cordillera was shown as ex- 

 tending into Caramuan Peninsula, and a southeastern volcanic region was 

 noted. This erroneous interpretation was based on the haehuring seen on 

 published maps. 



