This is how the theory of plate tectonics was developed :
The Beginning
Eduard Suess (1831 - 1914) first tried to answer the basic question : How do mountain ranges form? He said the Earth was contracting due to differences and changes in temperature. He went on to explain origins of oceans, continents, and the similarities of fossils that were distributed on the continents.
Later On...
Not everyone accepted the theory of a "contracting Earth", so in 1912 Alfred Wegener (1880 - 1930) proposed continental drift. According to this idea, about 200 million years ago all the continents were connected in a supercontinent called Pangea. This broke apart into separate continents that continued moving. He used the puzzle-like fit of the continents today to back-up his theory.
