In South America the line is continued by the active volcanoes of
Ecuador, Bolivia and Chile, but at many intermediate points in the chain
of the Andes extinct volcanoes occur, which to a great extent fill up
the gaps in the series. A small offshoot to the westward passes through
the Galapagos Islands. The great band of volcanoes which stretches
through the American continent is second only in importance, and in the
activity of its vents, to the band which divides the Pacific from the
Indian Ocean.
The third volcanic band of the globe is that, already spoken of,
which traverses the Atlantic Ocean from north to south. This series of
volcanic mountains is much more broken and interrupted than the other
two, and a greater proportion of its vents are extinct. It attained its
condition of maximum activity during the distant period of the Miocene,
and now appears to be passing into a state of gradual extinction.
Beginning in the north with the volcanic rocks of Greenland and Bear
Island, we pass southwards, by way of Jan Mayen, Iceland and the Faroe
Islands, to the Hebrides and the north of Ireland. Thence, by way of
the Azores, the Canaries and the Cape de Verde Islands, with some active
vents, we pass to the ruined volcanoes of St. Paul, Fernando de Noronha,
Ascension, St. Helena, Trinidad and Tristan da Cunha. From this great
Atlantic band two branches proceed to the eastward, one through Central
Europe, where all the vents are now extinct, and the other through the
Mediterranean to Asia Minor, the great majority of the volcanoes along
the latter line being now extinct, though a few are still active.
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