322 AUSTEALASIA. 



central part of the island, is the only cone which still ejects vapours and ashes. 

 The upraised cones scattered over Bougainville Strait are also composed of lavas, 

 but appear to have long been extinct. 



Choiseul, which forms the south-eastern continuation of Bougainville, and 

 which rests on the same submarine bank, presents a greater expanse of lowlands, 

 former marine and coralline beds. 



Yzabel and Malaita (Malanta), in the northern division of the Solomon group, 

 also consist of igneous ranges whose culminating crests rise respectively to 

 altitudes of 3,900 and 4,270 feet. But the eruptive masses in both islands are of 

 very ancient date, and have been modified to great depths by weathering. Up to 

 a height of 500 feet the hills are encircled by calcareous terraces slowy deposited 

 by the surrounding marine waters. 



The southern chain of the Solomons, running parallel with the northern, 

 begins with Treasury (Mono) Island, lying some 60 miles south of Bougainville. 

 Guppy describes this island as an anciently submerged volcanic peak covered by 

 several hundred feet of deposits, then encrusted with coral reefs, and finally 

 elevated above the sea to a height of nearly 1,200 feet. At one time it appears 

 to have subsided to a depth of about 1,800 fathoms, so that, adding its present 

 height, there must have been a subsequent upheaval of no less than 12,000 feet.* 



The group of islands stretching from Treasury in a south-easterly direction 

 contains some not yet entirely extinct cones. Vela la Velha (Vella Lavella), 

 3,000 feet high, has some fumeroles and a solfatara. Narovo, or Eddystone, is also 

 furrowed by crevices whence escape sulphurous vapours. But on New Georgia, 

 largest member of this cluster, nothing occurs except a range of quiescent or 

 extinct crests. When the Spaniards first reached these waters, the islet of Savo, 

 (Sesarga) at the north end of Guadalcanar, was in full eruption. Guadalcanar, 

 largest of the southern Solomons, is covered with superb cloud-capped mountains 

 rising to heights of from 6,000 to 8,000 feet. 



San Cristobal (4,100 feet) is also of volcanic origin; but all traces of activity 

 have disappeared, and the coast is now fringed by coralline headlands. Santa- 

 Ana, at the southernmost point of the Archipelago, is, like Treasury, an ancient 

 volcano, which, after subsiding some 1,500 or 2,000 fathoms below the surface, 

 was again upheaved with a calcareous deposit encrusting its primitive eruptive 

 rocks. 



Atolls and low islets are scattered over the Pacific to the east of the Solomons, 

 forming an irregular chain of extensive surf -beaten reefs. Here the atoll of 

 Ongtong-Java or Candelaria, called also Lord Howe or Leueneuwa, is especially 

 dreaded by mariners, its oval circuit of reefs having a periphery of at least 120 

 miles. The Solomons are also fringed in many places by barrier reefs, which 

 rise above the surface in deep waters. East of Yzabel one of these coralline 

 ramparts is reported to be considerably over 100 miles long ; New Georgia, 

 Bougainville and Choiseul are similarly fringed with reefs, which render more 

 than half of their seaboards inaccessible to shipping. The straits flowing between 



* The Solomon Islands, p. 102. 



