Relative dating evaluate geologic time
Historical geologists are scientists who study the Earth's past.They study clues left on the Earth to learn two main things: the order in which events happened on Earth, and how long it took for those events to happen.Seriation uses the assumption that once a tool was developed, its use would become more widespread.Stratigraphy uses the assumption that higher layers or strata were laid down after lower layers.
Although no absolute methods were available to establish actual dates, Lyell needed to assign very old dates to the strata to make them consistent with the long eons of time that would be necessary to meet the new uniformitarianism theory developed by James Hutton and himself.It means that we can use present-day processes to interpret the past. The laws of nature say that sea animals must live in the sea.That law has never changed, so the rock must have formed near the sea.These exceptional lengths of time seem unbelievable, but they are exactly the spans of times that scientists use to describe the Earth. When did the giant Rocky Mountains form and when did dinosaurs walk the Earth?To answer these questions, you have to think about times that were millions or billions of years ago.