zone are chiefly clothed with lofty pines;
while those at a lower elevation are adorned with chestnuts, oaks,
beech, and holm.

_Successive obliteration of these cones._--The history of the eruptions
of Etna, imperfect and interrupted as it is, affords us, nevertheless,
much insight into the manner in which the whole mountain has
successively attained its present magnitude and internal structure. The
principal cone has more than once fallen in and been reproduced. In 1444
it was 320 feet high, and fell in after the earthquakes of 1537. In the
year 1693, when a violent earthquake shook the whole of Sicily, and
killed sixty thousand persons, the cone lost so much of its height, says
Boccone, that it could not be seen from several places in Valdemone,
from which it was before visible. The greater number of eruptions happen
either from the great crater, or from lateral openings in the desert
region. When hills are thrown up in the middle zone, and project beyond
the general level, they gradually lose their height during subsequent
eruptions; for when lava runs down from the upper parts of the mountain,
and encounters any of these hills, the stream is divided, and flows
round them so as to elevate the gently sloping grounds from which they
rise. In this manner a deduction is often made at once of twenty or
thirty feet, or even more, from their height. Thus, one of the minor
cones, called Monte Peluso, was diminished in altitude by a great lava
stream which encircled it in 1444; and another current has recently
taken the same course--yet this hill still remains four or five hundred
feet high.

There is a cone called Monte Nucilla near Nicolosi, round the base of
which several successive currents have flowed, and showers of ashes have
fallen, since the time of history, till at last, during an eruption in
1536, the surrounding plain was so raised, that the top of the cone
alone was left projecting above the general level. Monte Nero, situated
above the Grotta dell' Capre, was in 1766 almost submerged by a current:
and Monte Capreolo afforded, in the year 1669, a curious example of one
of the last stages of obliteration; for a lava stream, descending on a
high ridge which had been built up by the continued superposition of
successive lavas, flowed directly into the crater, and nearly filled it.
The lava, therefore, of each new lateral cone tends to detract from the
relative height of lower cones above their base: so that the fl