Mr. Andersen explains the law of superposition and the principle of original horizontality. He uses an animation to explain how rock layers can accumulate over time.
Law of Superposition
Grade Level Grades 6-12
Paul Anderson does a phenomenal job explaining the Law of Superposition and how intrusions and faults can alter our perception in distinguishing older layers from younger layers. This is a great video lesson; short, sweet and to the point with detailed explanations.