chap, i.] PHYSICAL GEOGRAPHY. 9 



island in the world — owes its very existence to the same 

 intense volcanic activity which still occasionally devastates 

 its surface. 



The great island of Sumatra exhibits in proportion to 

 its extent a much smaller number of volcanoes, and a 

 considerable portion of it has probably a non-volcanic 

 origin. 



To the eastward, the long string of islands from Java, 

 passing by the north of Timor and away to Banda, are 

 probably all due to volcanic action. Timor itself consists 

 of ancient stratified rocks, but is said to have one volcano 

 near its centre. 



Going northward, Amboyna, a part of Bouru, and the 

 west end of Ceram, the north part of Gilolo, and all the 

 small islands around it, the northern extremity of Celebes, 

 and the islands of Siau and Sanguir, are wholly volcanic. 

 The Philippine Archipelago contains many active and 

 extinct volcanoes, and has probably been reduced to its 

 present fragmentary condition by subsidences attending 

 on volcanic action. 



All along this great line of volcanoes are to be found 

 more or less palpable signs of upheaval and depres- 

 sion of land. The range of islands south of Sumatra, a 

 part of the south coast of Java and of the islands east of 

 it, the west and east end of Timor, portions of all the 

 Moluccas, the Ke and Aru Islands, Waigiou, and the 



