Note: Volcanoes include many of the most conspicuous and
lofty mountains of the earth, as Mt. Vesuvius in Italy
(4,000 ft. high), Mt. Loa in Hawaii (14,000 ft.),
Cotopaxi in South America (nearly 20,000 ft.), which
are examples of active volcanoes. The crater of a
volcano is usually a pit-shaped cavity, often of great
size. The summit crater of Mt. Loa has a maximum length
of 13,000 ft., and a depth of nearly 800 feet. Beside
the chief crater, a volcano may have a number of
subordinate craters.