Volume 14 Australasia - dana ward's homepage

822 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, andwhich 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 resiDCctively toaltitudes of 3,900 and 4,270 feet. But the eruptive masses in both islands are ofvery ancient date, and have been modified to great depths by weathering. Up toa height of 500 feet the hills are encircled by calcareous terraces slowy depositedby 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 byseveral hundred feet of deposits, then encrusted with coral reefs, and finallyelevated above the sea to a height of nearly 1,200 feet. At one time it appearsto have subsided to a depth of about 1,800 fathoms, so that, adding its presentheight, there must have been a subsequent upheaval of no less than 12,000 feet.*The groiip of islands stretching from Treasury in a south-easterly directioncontains 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 alsofurrowed by crevices whence escape sulphurous vapours. But on New Georgia,largest member of this cluster, nothing occurs except a range of quiescent orextinct 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 .supei'b cloud-capped moimtainsrising to heights of from 6,000 to 8,000 feet.San Cristobal (4,100 feet) is also of volcanic origin; but all traces .of activityhave disappeared, and the coast is now fringed bj' coralline headlands. Santa-Ana, at the southernmost point of the Archipelago, is, like Treasury, an ancientvolcano, which, after subsiding some 1,500 or 2,000 fathoms below the surface,was again upheaved with a calcareous depo.sit encrusting its primitive eruptiverocks.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 ofOngtong-Java or Candelaria, called also Lord Howe or Leueneuwa, is especiallydreaded by mariners, its oval circuit of reefs having a periphery of at least 120miles. The Solomons are also fringed in many places by barrier reefs, whichrise above the surface in deep waters. East of Yzabel one of these corallineramparts is repiorted to be considerably over 100 miles long ; New Georgia,Bougainville and Choiseul are similarly fringed with reefs, which render morethan half of their seaboards inaccessible to shipping. The straits flowing between* T/ie Solomon Islands, i^.102.