What is catastrophism?
Theory that the geologic evidence is not as valid for uncovering Earth's history because it came from several catastrophic events.
Geologic principle the Earth's processes act in the same manner today as they have always throughout Earth's history.
Theory that Earth's rock layers formed in a global flood followed by the uplifting of rocks and mountain building over a short, violent period most likely in the recent past.
Theory that rocks form slowly over time through processes of volcanism, erosion, and sedimentation.