238 The Philippine Journal of Science 1922 
has been stated, the valleys vary from youthful in the igneous 
areas to mature in areas of less-resistant rocks. 
Vegetation, with its subduing effect, conceals the rocks more 
or less, and the shape of the outcrops cannot be determined. It 
seems definite, however, that the larger masses of limestone are 
in the interior and southern sections of Samar; that most of the 
igneous formations are in the center of the island and at the 
northwestern corner; that shales and marls, more or less flat, 
are common; and that the general strike of the peaks is slightly 
west of north. 
PHYSIOGRAPHY AND CLIMATE 
The rainfall is somewhat heavier on the east coast of Samar 
than elsewhere on the island, the annual fall there being more 
than 8,500 millimeters. This precipitation is exceeded only by 
the rainfall in the Benguet district, and at Iba, Zambales. The 
mean annual rainfall for the entire province is slightly more 
than 3,200 millimeters, with about 1,900 millimeters between 
November and February. Therefore, of all the provinces and 
subprovinces in the Archipelago, Samar ranks third in the 
amount of rainfall.® 
Since there is no marked dry season on this island, erosion 
is taking place all the time and is checked only by the vege- 
tation. The result on the topography of Samar as a whole is 
such that it is difficult to say whether or not a central cordillera 
exists. It is my opinion that there is no marked “backbone.” 
Instead, erosion (and one must not forget wave action) due to 
great amounts of rain, together with structural features, has 
cut the mountains, which formerly were more continuous, into 
ridges and hills. There is no great difference between the 
amount of rainfall on the east and west coasts. This is in 
marked contrast to the other large islands of the Archipelago, es- 
pecially those that have a definite cordillera, and this fact, alone, 
seems to indicate the nonexistence of a central mountain system 
that would act as a barrier to rain-laden winds. The only area 
of more-marked difference in the amount of rainfall is a small 
district around Calbayog, where the annual average is less than 
2,500 millimeters, while Catbalogan, about 38 kilometers south- 
east, has a much greater average. This is perhaps explained 
by the fact that the igneous area and the higher peaks near 
Calbayog protect the city from the northeast monsoons. It can 
* Coronas, Rev. José, S. J., The climate and weather of the Philippines, 
1903 to 1918, Census of the Philippine Islands 1 (1918) 342-408. 
