18 PEOPLES OF THE PHILIPPINES 
Mindanao. Here it becomes submerged in the Pacific 
Ocean, although its progress can be followed in its 
peaks. These constitute the chain known as the Sangir 
Islands, which lead directly to the northern extremity of 
the great island of Celebes, whose greatest length the 
range again traverses. 
Another and more westerly cordillera can be traced 
through the greater part of Luzon. It dips into the sea 
somewhat sooner than the eastern, but rises once more 
to form the backbone of the Island of Negros, and again 
the western range of Mindanao. Here it submerges 
again to form the Sulu Islands, of which the chief are 
Basilan, Sulu or Jolo, and Tawi-Tawi. These are not 
very large, but they are well known as the center of 
Mohammedan influence in the Philippines. The general 
course of the chain of Sulu islands is southwestward, and 
they reach very nearly to the northeastern tip of the 
great island of Borneo, in which the same folding of 
the earth’s crust of which they are part can be traced 
for a long distance. 
The fourth of the arms which the Philippines reach 
out toward other parts of the East Indies is formed by 
the islands of Mindoro and Palawan. These stretch in 
a southwesterly direction from central Luzon to north- 
ern Borneo. Mindoro is very near Luzon, but the chan- 
nel separating the two is deep, and there is also deep 
water between it and Palawan. Mundoro appears there- 
fore to have been cut off from the remainder of the group 
for a considerable geological period. This fact is re- 
flected. in certain peculiarities of its animal and plant 
life. It is interesting that in its human history it has 
also always maintained a certain aloofness. 
Palawan or Paragua, although very narrow, extends 
some 250 miles, and is the third longest island in the 
Philippines. The history of its human occupation is 

