e 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.

_Oceanic Islands._--By far the most extensive regions with sporadically
distributed volcanic vents, both active and extinct, are those which are
overspread by the waters of the ocean, where the vents emerge in the
form of islands. These are to be found in all the great oceans, the
Atlantic, the Pacific, and the Indian; but are especially numerous over
the central Pacific region. As Kotzebue and subsequently Darwin have
pointed out, all the islands of the Pacific are either coral-reefs or of
volcanic origin; and many of these rise from great depths; that is to
say, from depth