What was Charles Lyell's experiment?

Charles Lyell is primarily known for his work in geology rather than a specific experiment. His influential book, "Principles of Geology," published in the 1830s, emphasized the uniformitarian principle, which suggests that the geological processes observed in the present have been consistent over time. Rather than conducting experiments, Lyell used extensive field observations and comparisons of geological formations to argue against the then-dominant cataclysmic theories of Earth's history. His work laid the foundation for modern geology and significantly influenced Charles Darwin's thinking on evolution.