[1] For an interesting account of this range of volcanic islands see Kingsley's _At Last_. The grandest volcanic peak is that of Guadeloupe, rising to a height of 5000 feet above the ocean, amidst a group of fourteen extinct craters. But the most active vent of the range is the Souffrière of St. Vincent. In the eruption of 1812 this mountain sent forth clouds of pumice, scoriæ and ashes, some of which were carried by an upper counter current to Barbados, one hundred miles to the eastward, covering the surface with volcanic dust to a depth of several inches. [2] An excellent, and perhaps the most recent, map of this kind is that given by Professor Prestwich in his _Geology_, vol. i. p. 216. One on a larger scale is that by Keith Johnston in his _Physical Atlas_. [3] _Memoir on the Physical Geology and Geography of Arabia Petræa, Palestine_, etc., published for the Committee of the Palestine Exploration Fund (1886), p. 113, etc. [4] This mountain was ascended in 1837 by Mr. Taylor Thomson, who found the summit covered with sulphur, and from a cone fumes at a high temperature issued forth, but there was no eruption.--_Journ. Roy. Geographical Soc._, vol. viii. p. 109. [5] Humboldt, _Atlas der Kleineren Schriften_ (1853). [6] Ascended by Whymper June 29, 1880. He found the elevation to be 16,515 feet. [7] The arrangement of the volcanoes of Peru and Bolivia is also suggestive of a double line of fissure, while those of Chili suggest one single line. The volcanoes of Arequipa, in the southern part of Peru, are dealt with by Dr. F. H. Hatch, in his inaugural dissertation, _Ueber die Gesteine der Vulcan-Gruppe von Arequipa_ (Wien, 1886). The volcanoes rise to great elevations, having their summits capped by snow. The volcano of Charchani, lying to the north of Arequipa, reaches an elevation of 18,382 Parisian feet. That of Pichupichu reaches a height of 17,355 Par. feet. The central cone of Misti has been variously estimated to range from 17,240 to 19,000 Par. feet. The rocks of which the mountains are composed consist of varieties of andesite. [8] D. Forbes, "On the Geology of Bolivia and Southern Peru," _Quarterly Journal of the Geological Society_, vol. xvii. p. 22 (1861). [9] Darwin, _Structure and Distribution of Coral Reefs_, second edition, p. 186. [10] Erman, _Reise um die Welt_. [11] Milne, "Cruise amongst the Kurile Islands," _Geol. Mag._, New Ser. (August 1879). [12] See Daubeny, _Volcanoes_, Map I. [13] Sir A. Geikie has connected as a line of volcanic vents those of Sicily, Italy, Central France, the N. E. of Ireland, the Inner Hebrides and Iceland, of which the central vents are extinct or dormant, the extremities active. CHAPTER IV. MID-OCEAN VOLCANIC ISLANDS.