Planet Earth was formed during the Precambrian Time, which leads to Cambrian Period, where Igneous, Sedimentary, and Metamorphic Rocks were discovered, along with the Ozone Layer that allowed enough sunlight for life on Earth.
300 Million Years Ago...
The Paleozoic Era changed Earth into one supercontinent. They found fossils and kept track of them in the fossil record. The law of Superposition helped date each fossil found in rock.
23 Million Years Ago - Present Day ...
During the Mesozoic Era, huge reptiles, dinosaurs, shook the Earth for about 140 million years until the Earth's atmosphere changed and killed the dinosaurs.
The plate tectonics moved and caused the supercontinent to split, causing Pangea.
During the Cenozoic Era, scientist discovered a way to keep geological time into chronical units, using the Geological Timescale. They were able to trace back how Earth originated, when there was an explosion called the Big Bang Theory.
Scientist noticed that the ocean floor has different patterns because convergent and divergent plate boundaries push and pull against each other.