Principles of Radiometric Dating Next Lesson What is Relative Dating? - Law of Superposition, Principles of Original Horizontality & Cross-Cutting Relationships - Law of Superposition, Principles of Original Horizontality & Cross-Cutting Relationships. What is Relative Dating? - Law of Superposition, Principles of Original Horizontality & Cross-Cutting Relationships. 6 principles of Relative Dating. is used by scientist to determine relative rock ages of sedimentary rock. The youngest rock layers are at the top of rock. Learn how inclusions and unconformities can tell us stories about the geologic past. Email Email is required. Studying for Earth Science I'm not interested in CLEP. Principles of Radiometric Dating. The regular order of the occurrence of fossils in rock layers was discovered around by William Smith. Relative Dating - Example 1