Oahu is an example of a volcanic island

Oahu is an example of a volcanic island. Volcanoes which were active long ago have been worn down and cut into valleys and ridges and are now represented by the Koolau Range and the Waianae Mountains. Diamond Head, Punchbowl, and Koko Head are volcanoes which were active such a short time ago that their original. form has not been much changed.

The mountains reach a height sufficient to check the moistureladen trade winds, thus producing a fairly heavy rainfall on the windward side; but they are not high enough or continuous enough to prevent winds and rain from coming to the leeward side at Honolulu, Pearl Harbor, and Ewa. The valleys are broad enough to serve as fields for taro, and the small streams which run in most of them supply water enough for necessary irrigation. Near the seashore are groves of coconuts, and in the valleys and on the ridges at different elevations are the native trees and shrubs -- the hau, the ohia, the kukui, the koa,pandanus, and other species of plants suitable for food, for making of clothing, for the building of homes and canoes, for making cooking utensils and farming implements, and for use as medicine. On the island are more than four hundred kinds of native flowering plants. In the forests are birds which may be used for food and whose feathers are used for decoration. The coast is bordered by coral reefs, through which are passages at the mouths of the principal valleys. These passages permit the entrance of boats to safe landing places. The shallow waters at the mouths of streams make favorable sites for artificial fishponds; and the reefs themselves and the waters beyond furnish an abundant supply of sea food. On such an island as Oahu a fairly large number of people could live comfortably, either in villages or scattered about, and they could support themselves by hunting, agriculture, and fishing.

Most volcanic islands in the Pacific are well suited to human occupation; in olden times as well as to-day islands of this class, like Tahiti, Samoa, the Marquesas, Hawaii, Solomon Islands, Ponape, and Kusaie, were populated by a larger number of people in a more advanced stage of development than were the coral islands or the raised coral islands.