rived at by a comparison of the violence and
extent of volcanic and seismic phenomena within the period of history
with those of pre-historic periods.

At first sight we might be disposed to give to the question an
affirmative reply when we remember the eruptions of the last few years,
and add to these the volcanic outbursts and earthquake shocks which
history records. The cases of the earthquake and eruption in Japan of
November, 1891, where in one province alone two thousand people lost
their lives and many thousand houses were levelled[1]; that of Krakatoa,
in 1883; of Vesuvius, in 1872; and many others of recent date which
might be named, added to those which history records;--the recollection
of such cases might lead us to conclude that our epoch is one in which
the subterranean volcanic forces had broken out with extraordinary
energy over the earth's surface. Still, when we come to examine into
the cases of recorded eruptions--especially those of great violence--we
find that they are limited to very special districts; and even if we
extend our retrospect into the later centuries of our era, we shall find
that the exceptionally great eruptions have been confined to certain
permanently volcanic regions, such as the chain of the Andes, that of
the Aleutian, Kurile, Japanese, and Philippine and Sunda Islands, lying
for the most part along the remarkable volcanic girdle of the world to
which I have referred in a previous page. Add to these the cases of
Iceland and the volcanic islands of the Pacific, and we have almost the
whole of the very active volcanoes of the world.

Then for the purposes of our inquiry we have to ascertain how these
active vents of eruption compare, as regards the magnitude of their
operations, with those of the pre-historic and later Tertiary times. But
before entering into this question it maybe observed, in the first
place, that a large number of the vents of eruption, even along the
chain of the earth's volcanic girdle, are dormant or extinct. This
observation applies to many of the great cones and domes of the Andes,
including Chimborazo and other colossal mountains in Ecuador, Columbia,
Chili, Peru, and Mexico. The region between the eastern Rocky Mountains
and the western coast of North America was, as we have seen, one over
which volcanic eruptions took place on a vast scale in later Tertiary
times; but one in which only the after-effects of volcanic action are at
present in operation. W