re
two very striking exceptions, which we must now proceed to notice.

In the very centre of the continent formed by Europe and Asia, the
largest unbroken land-mass of the globe, there rises from the great
central plateau the remarkable volcanoes of the Thian Shan Range. The
existence of these volcanoes, of which only obscure traditional accounts
had reached Europe before the year 1858, appears to be completely
established by the researches of recent Russian and Swedish travelers.
Three volcanic vents appear to exist in this region, and other volcanic
phenomena have been stated to occur in the great plateau of Central
Asia, but the existence of the latter appears to rest on very doubtful
evidence. The only accounts which we have of the eruptions of these
Thian Shan volcanoes are contained in Chinese histories and treatises on
geography.

The second exceptionally situated volcanic group is that of the Hawaiian
Islands. While the Thian Shan volcanoes rise in the centre of the
largest unbroken land-mass, and stand on the edge of the loftiest and
greatest plateau in the world, the volcanoes of the Hawaiian Islands
rise in the northern centre of the largest ocean and from almost the
greatest depths in that ocean. All round the Hawaiian Islands the
sea has a depth of from 2,000 to 3,000 fathoms, and the island-group
culminates in several volcanic cones, which rise to the height of nearly
14,000 feet above the sea-level. The volcanoes of the Hawaiian Islands
are unsurpassed in height and bulk by those of any other part of the
globe.

With the exception of the two isolated groups of the Thian Shan and
the Hawaiian Islands, nearly all the active volcanoes of the globe are
situated near the limits which separate the great land-and-water-masses
of the globe--that is to say, they occur either on the parts of
continents not far removed from their coast-lines, or on islands in
the ocean not very far distant from the shores. The fact of the general
proximity of volcanoes to the sea is one which has frequently been
pointed out by geographers, and may now be regarded as being thoroughly
established.

VOLCANOES PARALLEL TO MOUNTAIN CHAINS

Many of the grandest mountain-chains have bands of volcanoes
lying parallel to them. This is strikingly exhibited by the great
mountain-masses which lie on the western side of the American continent.
The Rocky Mountains and the Andes consist of folded and crumpled masses
of altered strata wh