Under the
first name are comprised those which constitute the central point of many
active mouths of eruption, distributed almost regularly in all directions;
under the second, those lying at some little distance from one another,
forming, as it were, chimneys or vents along an extended fissure. Linear
volcanoes again admit of further subdivision, namely, those which rise like
separate conical islands from the bottom of the sea, being generally
parallel with a chain of primitive mountains, whose foot they appear to
indicate, and those volcanic chains which are elevated on the highest ridges
of these mountain chains, of which they form the summits.*
[footnote] *Leopold von Buch, 'Physikal. Beschreib. der Canarischen
Inseln', s. 326-407. I doubt if we can agree with the ingenious Charles
Darwin ('Geological Observations on Volcanic Islands', 1844, p. 127) in
regarding central volcanoes in general as volcanic chains of small extent on
parallel fissures. Friedrich Hoffman believes that in the group of the
Lipari Islands, which he has so admirably described, and in which two
eruption fissures intersect near Panaria, he has found an intermediate link
between the two principal modes in which volcanoes appear, namely, the
central volcanoes and volcanic chains of Von Buch (Poggendorf, 'Annalen der
Physik', bd.
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