Historical geology is the study of Earth's past, including its physical and biological evolution. There are various alternative terms that can be used to describe this particular branch of science, such as paleogeology, stratigraphy, and geohistory. Paleogeology is a term that more specifically refers to the study of the Earth's ancient past, while stratigraphy focuses on the study of rock layers and how they were formed. Geohistory is a broader term that encompasses all aspects of Earth's history, including its past climate, landforms, and ecosystems. Regardless of the term used, historical geology is an essential field of study for understanding the planet's past, present, and future.