Coral Reefs; Volcanic Islands; South American Geology

Coral Reefs, Volcanic Islands, South American Geology is a book by Charles Darwin. The editorial note says the books reprinted are in some respects more technical in their subjects and style than Darwin's Journal, and will never lose their value and interest for the originality of the observations they contain. The note adds that many parts of them are admirably adapted for giving an insight into problems regarding the structure and changes of the earth's surface.

The text says the scoriaceous fragments and the calcareous matter are associated in the most irregular manner, sometimes in obscure beds, but more generally as a confused breccia. Sir H. De la Beche has had some of the purest specimens analysed to discover whether they contained much magnesia, and only a small portion was found, such as is present in most limestones. The text describes Gouap (Eap of Chamisso) as a high island with a reef more than a mile distant in most parts from the shore, and two miles in one part.