Stratigraphy is a branch of geology that focuses on studying and interpreting the layers of rocks (strata) found in the Earth's crust. It involves analyzing the order and relative position of these rock layers to understand the geological history of an area. Stratigraphy seeks to determine the age of rocks, the environments in which they formed, and the geological processes that have shaped the Earth over time. This field of study is crucial for understanding the history of the Earth, the evolution of life, and the formation of natural resources.