In 1830, Charles Lyell (effectively Charles Darwin's mentor) published his Principles of Geology as an attempt to explain past geological changes by mechanisms that can be studied in the present.

Lyell's frontispiece was the remains of the ancient Greek Temple of Serapus at Puzzuoli, near Naples in Italy. Known forces of land subsidence and earthquakes could account for its unusual appearance today. It had been built on land, and then subsided over a millennium, which allowed marine molluscs to leave the high water mark. The remains of the temple had then been raised up again in an earthquake in September 1438 to its present position. It was an example of how known forces and mechanisms could be used to explain past events. Continuity was essential, but the known forces could vary in their intensity over time.