Oahu, comprising 598 square miles, and Maui, comprising 728 square miles, are two of the major islands of the Hawaiian group, about 58 miles apart, with Molokai lying between them. Both are volcanic doublets. Oahu is noted for its port of Honolulu, and Maui for its dormant eroded crater of Haleakala. Surrounding Oahu is a narrow coastal plain which emerged from the sea in Pleistocene time, and which, in places, reaches 6 miles in width. It consists of reef limestone and terrigenous deposits. Surrounding all but the east and west ends of Oahu is a fringing reef. Notably different from Oahu is Maui, which has only a few narrow strips of coastal plain, and these contain no reef limestone. The absence of emerged reefs on Maui is, however, not surprising in view of the relative paucity of living reef at the present time.
The shore lines described below were . . .