The Principles of Physical Geology

The principles of physical geology are foundational ideas that explain how Earth’s materials and processes work. They include the law of uniformitarianism, which states that Earth's processes happen gradually and have been consistent over time; the principle of superposition, meaning younger rocks are found above older ones; and the principle of original horizontality, indicating sediments are deposited flat before they are disturbed. These principles help scientists interpret Earth's history, understand rock formations, and predict natural events, by analyzing rock layers, minerals, and geological features in a systematic way rooted in observation and reasoning.