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The only rock of non-volcanic origin in these islands consists of granular limestone and clay slate forming the ridge of Mount St. Elias, which rises to a height of 1887 feet at the south-eastern side of the island of Thera, crossing the island from its outer margin nearly to the interior cliff, so that the volcanic materials have been piled up along its sides. The rocks of St.
From the extreme eastern bend of this belt at Banda, we pass onwards for 1,000 miles over a non-volcanic district to the volcanoes observed by Dampier, in 1699, on the north-eastern coast of New Guinea, and can there trace another volcanic belt through New Britain, New Ireland, and the Solomon Islands, to the eastern limits of the Archipelago.
In the same way beneath the ground in non-volcanic countries we may discover at a great depth in the older, much-changed rock a vast number of these crevices, varying from a few inches to a hundred feet or more in width, which have been filled with lavas, the rock once molten having afterward cooled.
Thus the North Atlantic, the coasts of which appear to have gone inland for a great distance in geologically recent times, is non-volcanic; while the Pacific coast, which for a long time has remained in its present position, has a singularly continuous line of craters near the shore extending from Alaska to Tierra del Fuego.
The flanks of this volcano are diversified by several fresh craters and lava-streams, while hot springs burst out with a hissing noise on its southern flank, showing that molten matter lies below at no very great depth. This island probably lies along the dividing line between the non-volcanic and volcanic region of the Mediterranean, and is consequently liable to intermittent eruptions.
The great island of Sumatra exhibits, in proportion to its extent, a much smaller number of volcanoes, and a considerable portion of it has probably a non-volcanic origin. To the eastward, the long string of islands from Java, passing by the north of Timor and away to Panda, are probably all due to volcanic action.
They, again, differ from the animals found in Borneo, Java, and Sumatra, which are mostly identical with those of Asia. "A striking contrast will also be found in the scenery of the islands of volcanic and non-volcanic origin. A volcanic belt passes from the north, through the Philippine Islands, down to the north end of Celebes.
Though on the first formation of the volcano, masses of non-volcanic rock may be torn from the chimney or pipe of the mountain, only slightly fused externally owing to the bad conducting power of most rocks, and hurled to a distance; and though at the beginning of a subsequent eruption the solid plug of rock which has cooled at the bottom of the crater, or, in fact, any part of the volcano, may be similarly blown up, the bulk of the solid particles of which the volcano itself is composed is derived from the lake of lava or molten rock which seethes at the orifice.
During the eruption a roar as of distant artillery could be heard in the middle of Java, fully 400 miles from the scene. The form of the islands prevents the existence of very large rivers; the largest are in Borneo, the only non-volcanic island in the archipelago which can boast of three navigable rivers each about 400 miles long.
With the great island of Borneo as a solid, non-volcanic central core, a line of volcanic islands extends from Chedooba off the coast of Pegu through Sumatra, Java, Sumbawa, Flores, and, reaching the Moluccas, stretches northwards through the Philippines into Japan and Kamtschatka.
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