Plate Tectonics is now a generally accepted geographical term used to describe the movement of the Earth's crust, forming the changes in continent shape that has created the familiar outline we know today.
The History of the Plate Tectonics Theory
The theory of plate tectonics is relatively recent. The first observation that lead to its development was in 1912, but it was not given any true attention until the 1960's. Alfred Wegener (1880-1930), having looked at the shapes of the continents and how the coastlines of many seem to line up, made a proposal that the continents had once been completely joined together to form a supercontinent. He called this Pangaea, but he did not have any geological evidence to prove this. As a result his theory was overlooked for many years and fell out of favour.