The Principles of Stratigraphy (Document)

Stratigraphy is the study of rock layers (strata) and their relationships. Key principles include: 1. **Law of Superposition**: In undisturbed layers, older rocks lie beneath younger ones. 2. **Principle of Original Horizontality**: Layers are originally deposited horizontally. 3. **Principle of Lateral Continuity**: Layers extend in all directions until they thin out or encounter a barrier. 4. **Principle of Cross-Cutting Relationships**: If a rock or fault cuts through another, it must be younger. These principles help scientists understand Earth's history and the timing of geological events.