I HE PHILIPPINE ISLANDS 259 



largely contributed to their formation and shaping, as is testified, 

 not only by the existence of active volcanoes, but by the still 

 larger number of mountains which show evidences of former 

 igneous activity, the traces of its effects on the surrounding 

 country, and the abundance of thermal springs which are found 

 in different localities, in which tbe temperature of the water 

 ranges from 180° Fahrenheit to the boiling point. Although sit- 

 uated in a region peculiarly adapted to the growth of corals, they 

 do not exist to any great extent on the coasts of the Philippines. 

 Occasional traces, sometimes amounting to a fringing reef, are 

 met with in favorable places along the west coast of Luzon and 

 some of the other islands of the group. This scarcity of coral 

 formation may be accounted for by the presence of volcanic fires 

 and the occasional deluges of hot water emanating from their 

 outlets, which prevent the growth of the polyps. All the islands 

 are generally hilly and mountainous, but none of the summits 

 much exceed 8,000 feet, in height. The loftiest peaks are, per- 

 haps, Apo and Malindang, in Mindanao ; Halcon, in Mindoro, 

 and Mayon, in Luzon. The latter is an active volcano, which 

 has been the scene of several disastrous eruptions within the past 

 hundred years. 



As a consequence of these subterraneous forces, earthquakes 

 are frequent and violent. An English writer says : 



"The destructive ravages and changes produced by earthquakes are 

 nowhere more remarkable than in the Philippines. They have over- 

 turned mountains; they have filled up valleys; they have desolated ex- 

 tensive plains ; they have opened passages for the sea into the interior 

 and from lakes into the sea.". 



That this is not an exaggeration is proved by historical rec- 

 ords, which contain many accounts of such disasters since the 

 Spaniards first occupied the territory, and proofs that they have 

 produced great geographical changes. 



" In that of 1627 one of the most elevated of the mountains of Cagayan 

 disappeared. In 1675 in the island of Mindanao a passage was opened 

 to the sea and a vast plain was emerged." 



The more recent of these convulsions occurred in 1863 and 

 1880, both of which caused great destruction of property. In 

 the former the loss of life was greater, but the more massive 

 buildings in the old city of Manila suffered more during the 

 latter, the cathedral and many other edifices being completely 

 wrecked. 



