At the Few York meeting* of the Society I gave some account of a singular depression on the southwest slope of Mauna Loa, calling it a caldera. My information concerning it came primarily from descriptions of the topography given by Mr J. S. Emerson, of the Hawaiian Trigonometrical Survey, which form the basis of the official map of Hawaii published in 1901. Mr Emerson had read a paper on the subject before the Social Science Association of Honolulu in October, 1895, which was published in the American Journal of Science in December, 1902, under the title of “Some characteristics of Kau.” During the past summer (1905) I have visited the locality, and now proceed to describe the ascertained facts and to draw certain conclusions therefrom.
A caldera is conceived by Captain C. E. Dutton, who proposed the name, to be an immense depression “formed by the dropping . . .