What is Catastrophic?

Catastrophism (proposed by French zoologist Georges Cuvier) is a geologic theory which states that Earth changed by sudden, violent processes. It states that the appearance of new fossils in each rock layer resulted from other species' moving into the area from elsewhere after each catastrophic event.

Its contrasting argument, uniformitarianism (proposed by English geologist Charles Lyell in the 1830s), states that Earth changes slowly over long periods of time by uniform processes such as erosion.