THE MALAYAN ARCHIPELAGO. 119 



In conclusion, I must not forget to mention the very 

 important volcanic group of Laguna. Lying between the Zam- 

 bales-Paragua cordillera on the west and the main sierra on 

 the east, that portion of South Luzon, lying to the south of 

 Manila, was submerged during post-Eocene time, and then 

 effusive rocks got piled up at different periods, creating the 

 andesitic Majayjay and the basaltic Taal. On this account, a 

 portion of the sea became barred in, forming the Lake of Bay, 

 and the Bay of Manila on the north. The water of Bombon 

 should be considered as a crater-lake, in the middle of which 

 appears the central cone of Taal, which is constantly emitting 

 steam and vapours. Besides these two volcanoes, there are 

 Magniling and Sosoncambing, each having its own crater. The 

 andesitic Arayat, north of Manila, is an extinct crater, and the 

 cone of Halcon in Mindoro, is the second in height of all the 

 volcanoes of the Philippine Islands. 



