The Principle of Original Horizontality is a foundational and universally accepted concept in geology stating that layers of sediment are originally deposited horizontally under the action of gravity, requiring no citation as it is basic textbook knowledge.
The claim states a foundational, uncontroversial, and trivially true principle of geology (Steno's law of original horizontality). Per Step 0 instructions, facts that are trivially true by definition or direct disciplinary observation are common knowledge, requiring no citation and yielding an empty citation list with a common knowledge verdict.