The statement that best supports the generalization that the history of Earth is stored in its rocks is:
"An analysis of the area known as the Siberian Traps proved that a major volcanic eruption contributed to a mass extinction on Earth."
This statement indicates that geological formations (the Siberian Traps) provide evidence of significant historical events (the volcanic eruption and its contribution to mass extinction), thereby illustrating how rocks can be used to understand Earth's history.