In the Hawaiian Archipelago (or Sandwich Island group), we find Mauna Loa, according to Wilkes, 12,900 feet in height, which does not present any cone of volcanic scoriæ (resembling, in this particular, the volcanoes of the Eifel), but has emitted streams of lava. The lava basin of Killauea, 13,000 feet in its greatest, by 4800 in its smallest diameter, is not a _solfatara_, but a true lateral vent on the flank of the powerful Mauna Loa itself, exactly resembling the less elevated sheet of lava of Arak. Mauna Kea is 180 feet higher than Mauna Loa, but is extinct. Tafoa and Amangura, in the Tonga group, are still in eruption, the last discharge of lava having occurred in July, 1847. The volcano of Tanna was in full eruption during Capt. Cook's Voyage of Discovery in 1774, as was also the volcano of Ambrym, west of Malicollo in the archipelago of the New Hebrides. At the south point of New Caledonia, lies Matthew's Rock, a small smoking rocky island. The volcano of Santa Cruz, N.N.W. of Tina Kora, with periodical eruptions occasionally occurring at intervals of 10 minutes, had been already noticed as a volcano by Mendana, so far back as 1595. In the Salomon Archipelago, there is found the volcano of Sesarga, while others are said to be in full activity in the Marianas or Ladrones, just like those of Guguan, Pagon, and El Volcan Grande de Asuncion, which appear to have broken forth along a line that follows the meridian. In New Britannia, three conical mountains were observed vomiting streams of lava, by Tasman, Carteret, and Labillardière. There are two volcanoes in full activity on the north-east coast of New Guinea, opposite Admiralty Islands, which themselves are so rich in obsidian. In New Zealand, numerous regions abound in basaltic and trachytic rocks. Of active volcanoes there are Puhia-i-Wakati (the volcano of White Island), and the lofty cone of Tongariro (5816 feet). To the absence of centres of volcanic agency in New Caledonia, where sedimentary formations and seams of coal have recently been discovered, is ascribed the vast development of coral reefs. Dana was the first to ascend the Peak of Tafua, in the Island of Upolu, one of the Samoa group, not to be confounded with the still active volcano of Tafoa, south of Amangura, in the Tonga Archipelago. Dana found in it a crater overgrown with thick forest. So, too, on the isolated Vaihu or Easter Island group, there is found a range of conical mountains with craters, but inactive.