On Craters of Denudation, with Observations on the Structure and Growth of Volcanic Cones

Abstract

I n the first edition of my ‘Principles of Geology’ published in 1830 (vol. i. ch. 30), I explained the grounds of my objection to the theory previously advanced by Baron von Buch to account for the origin of the Caldera of Palma, the Gulf of Santorin, and other bowl-shaped cavities of large dimensions, for which he proposed the name of “Craters of Elevation.’ I regarded the circular escarpments surrounding these vast cavities as the remnants of cones of eruption, the central parts of which had been destroyed, and I conceived that the removing cause had been chiefly, if not wholly, engulfment. In the second edition of my ‘Principles,’ published in 1832, or two years later, I discussed more particularly the origin of the single deep gorge, which in Palma, Barren Island, and other so-called elevation-craters, forms a breach in the circular range of cliffs, surrounding the central cavity. This ravine or narrow passage I attributed “to the action of the tide during the gradual emergence from the sea and upheaval of a volcanic island” (ch. 22. vol. i. p. 452), and I at the same time alluded to its analogy to the single passage leading into the lagoons of many annular coral islands of Atolls. Although I then distinctly announced this theory in regard to such narrow ravines, the idea had not occurred to me that the same denuding power of the waves and tides, which were thus appealed to as adequate to remove the rocks once filling such deep