490 



AUSTEALASIA. 



for the highest volcanoes and vastest cauldrons of seething lavas are found in 

 Hawaii, the largest member of the group, at its south-eastern extremity. The other 

 islands are also studded with cones and craters ; but here the fiery energy is much 

 weaker, or is reduced to a few thermal springs. In the extreme north-west the 

 long-extinct craters have been obliterated, and the heights are now clothed with 

 an exuberant vegetation. Here also the coral reefs are far more numerous than off 

 the coast of Hawaii, where the noxious gases prevent the development of coral 

 life. 



In the island of Hawaii the southern volcano of Mauna-Loa, or the " Great 

 Mountain," rises to a height of 13,760 feet, or about 3,000 feet above the vege- 



Fig. 220.— Hawaiian Islands. 



Scale 1 : 6,500.000 



160° 



West br b'-eenwicln 



Depths 



table zone. The crater, or rather group of craters, collectively named the Mokua- 

 veoveo, open on the very summit of the mountain, so as to form a symmetrical 

 cavity disposed in the direction from north to south. In the centre lies the vast 

 primitive crater, which has a mean diameter of about 2,200 yards and a depth of 

 over 1,000 feet. Mounds of scoriae, some in ignition, some extinct, rise from the 

 bottom of this pit, north and south of which two semicircular terraces over 400 

 feet high represent two halves of a crater inscribed, so to say, on the periphery 

 of the central opening. Vast lava streains have been discharged from the very 

 rim of Mauna-Loa, as in 1880, when about 2,200,000,000 cubic feet of burning 

 matter flowed down the slopes of the mountain. But the molten lavas mostly 

 escape from openings far below the upper cone. Thus in 1855 such a stream over- 



