190 "^he Philippine Journal of Science 



1916 



of March 11, 1914, on the summit of Mount Amuyao, 2,700 

 meters' elevation, when the thermometer registered 7 .8 C. At 

 Bontoc, 945 meters' elevation, the temperature reaches this point 

 in January. 



As to the rainfall I can only say that at certain seasons (June 

 to October in Bontoc and Kalinga) it is at times excessive, but 

 the season differs in the several subprovinces. Again we find 

 the Polis Range the great dividing line. On the eastern and 

 southern side of this prominent topographic feature, in Ifugao, 

 for instance, the seasons correspond more nearly to those which 

 are found to obtain in the Cagayan Valley. 



HYDROGRAPHY 



The prominent features of the hydrography are the two prin- 

 cipal streams, the Abra, rising on the slopes of Mount Data, 

 flowing almost due north approximately to the town of Dolores, 

 where it turns west by south and cuts through the coast range 

 just south of Vigan, and the Chico which flows northeast and 

 finally reaches the sea by way of the Cagayan. Neither of these 

 streams is navigable in the area under discussion in this report. 

 The main drainage in this area, then, is along well-defined, and 

 doubtless structural, north and south lines with, of course, the 

 usual attendant tributaries, which are influenced by purely local 

 and minor topographic features. 



VEGETATION 



The region as a whole cannot be said to be a forest region. 

 There are areas, such as those on the slopes of the Polis Range, 

 which are fairly well-forested, chiefly with pine (Pinus insularis 

 Endl.). There are other parts of the territory clad only with 

 scattered timber, little of which is suited for anything but fuel, 

 as around Bontoc and Lubuagan, while in Ifugao, particularly 

 around Banaue, there is scarcely a stick of standing timber. 



There is, of course, to be noted the usual vertical differentiation 

 in the plant distribution quite constant throughout the Malayan 

 province — that is, tropical flora at the lower elevations ; from 760 

 to 1,830 meters, usually pine (not always, however) ; above this, 

 the so-called "mossy forest;" and finally on the highest points 

 only grass. The reader is referred to Merrill's ■ article on the 

 flora of Mount Pulog, the highest peak in Luzon, situated just 

 to the south of the country explored by me. What Merrill found 

 on that mountain, I think, is typical of northern Luzon. 



'This Journal, Sec. C (1910), 5, 287-370; 371-403. 



