the big bang happened 13.8 billion years ago and it formed the universe its know as the big bang theory.
earth is around 4.5 billion years old and the atmosphere started to form.This layer is one of the first layers of the geologic timescale.
Cyanobacteria started to form and used photosynthesis and there was more oxygen in the world and this is when animals started to evolve and the ozone started to form.
then Pangea started to break apart because the tectonic plates or plate tectonics started to break apart also known as plate boundaires divergent and plate boundaires convergent is when two tectonic plates crash into each other.
with The law of superposition we can find fossil records of extincted animals or plants and a and a lot of a lot of Igneous,Metamorphic and Sedimentary rocks have been formed. Their is a lot of layers of rocks and they are all in the geologic timescale.