How islands appeared—and vanished—in Loudon’s account

Loudon describes two distinct ways land can appear, not one process at different speeds.

• Monte Nuovo illustrates a sudden volcanic change to an existing coast. In 1538, an eruption opened a gulf, expelled pumice, lava blocks and ash, and left a hill where a town and the Lucrine Lake had been. It is her example of land being rapidly reshaped, not of a coral island growing^[1][2].
• The newly risen island illustrates that volcanic land need not last. Loudon reports that a boat crew found it rising from the sea; the first island they examined then diminished daily and had disappeared by the following October^[3].
• Lagoon islands form gradually in her account. Generations of coral polyps add calcareous structures; the reefs then catch sand and earth, seeds arrive by ocean currents, and growing plants add more soil as they decay^[4][5].

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