Relative dating superposition
The bottom layer because it logically had to be laid down first must be older.The layers on top could only be laid down on top of the bottom layer so must be younger.
Relative dating does not provide actual numerical dates for the rocks.
The geological events in Earth's history are a series of processes that have changed the structure of Earth’s crust.
Geologists use scales to date these geological events and to measure the age of the Earth.
Fossils are important for working out the relative ages of sedimentary rocks.
Throughout the history of life, different organisms have appeared, flourished and become extinct.