Answer:
A Continental drift theory
Explanation:
The continental drift theory was popularized by Alfred Wegener at the beginning of the past century (early 1900s). He stated that continents are land masses that float on magma, and they are continuously moving and drifting over the magma oceans that lie underneath. Wegener believed that all continents were once part of one single large continent called Pangea and that they started drifting away millions of years ago until they reached their current position. He also stated that the continents are still moving, but the movement is very slow and we can only notice it during earthquakes and tremors.
This theory has been updated and replaced by the study of plate tectonics.