Oahu is one of the newly annexed Hawaiian islands. It possesses the best harbor in the whole group, and is therefore the most important location for business, the chief city, Honolulu, containing 40,000 inhabitants and being situated about 2,100 miles southwesterly from San Francisco. The city is surrounded by an interesting group of extinct secondary volcanoes, resting on ancient basaltic flows and adjacent to a coral reef which girdles the whole island.
First discovered in the fourteenth century, the islands were rarely seen by civilized people before 1820, since which time visits of investigation have gradually become quite numerous. A multitude of allusions to volcanic or coralline formations are made in the writings of travelers, historians, and missionaries, such references being primarily to the existing active volcanoes on the island of Hawaii and sparingly to the phenomena on Oahu, all of which will be passed by in this sketch . . .