No. 3. — The Coral Reefs of the Hawaiian Islands. By Alexander Agassiz. Before giving the results of ray observations on the Coral Reefs of the Sandwich Islands, it may be useful to recapitulate the salient points of the older theories of the formation of the coral reefs, from Chamisso's (1815-1818) to Darwin's (1842), as well as the modification of the lat-ter by Dana (1838-1842, 1849), and to enumerate briefly the objections which have been made to the general application of the theory of sub-sidence to the special cases examined by later investigators, from Agassiz (1851) to the present time. I need only refer to the earlier views of Forster, who imagined coral reefs to have been built up from the bottom of the ocean, a view which was naturally untenable after the observations of Quoy and Gaymard on the limits of depth at which corals apparently thrive, as well as the later observations of Ehrenberg on the coral reefs of the Red Sea. Darwin, it should be remembered, examined only the Great Chagos Bank, and based his speculations on the observations he made on this single group, supplementing the knowledge, however, by a most exhaust-ive analysis of the observations and descriptions of others, and a most thorough examination of the hydrographic charts which had any bearing on the subject. But no naturalist has had opportunities to make a personal examination of the conditions of growth of corals and of coral islands such as have been enjoyed by Dana, as geologist of the United States Exploring Expedition. His Report on Coral Reefs and Islands, published in 1849, contains a full account of his own observa-tions (1838-1842) on the Hawaiian Islands, the Society Islands, the Samoa and Viti groups, and his theories are based upon his own experi-ence, far wider than that of any other Vrriter on the subject. He has therefore drawn but little either from the descriptions of the voyagers of the early part of this century, or from the hydrographic charts, both of which form so essential a part in the Darwinian theory of coral reefs. An examination of the hydrographic charts of the coral reefs, while interesting, can lead to no so\md conclusion. Well as I know the Florida reefs and part of the Bahamas, as well as the majority of the West India coral reefs, I should hesitate to base any general conclusions VOL. XVII. — NO. 3.
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