Volcanic islands exist and generally abound in the ocean and greater
seas; every now and then we observe a new one forming as a small
island, which is apt to be washed away by the sea shortly after the
eruption ceases, the disappearance being speedy, for the reason that
the volcanic ashes of which these cones are composed drift away like
snow before the movement of the waves.

If the waters of the ocean and seas were drained away so that we could
inspect the portion of the earth's surface which they cover as readily
as we do the dry lands, the most conspicuous feature would be the
innumerable volcanic eminences which lie hidden in these watery
realms. Wherever the observer passed from the centres of the present
lands he would note within the limits of those fields only mountains,
much modified by river action; hills which the rivers had left in
scarfing away the strata; and dales which had been carved out by the
flowing waters. Near the shore lines of the vanished seas he would
begin to find mountains, hills, and vales occasionally commingled with
volcanic peaks, those structures built from the materials ejected from
the vents. Passing the coast line to the seaward, the hills and dales
would quickly disappear, and before long the mountains would vanish
from his way, and he would gradually enter on a region of vast rolling
plains beset by volcanic peaks, generally accumulated in long ranges,
somewhat after the manner of mountains, but differing from those
elevations not only in origin but in aspect, the volcanic set of peaks
being altogether made up of conical, cup-topped elevations.

A little consideration will show us that the fact of volcanoes being
in the limit to the sea floors and to a narrow fringe of shore next
certain ocean borders is reconcilable with the view as to their
formation which we have adopted. We have already noted the fact that