Wegener hypothesised that all of the modern day continents had previously been clumped together in one supercontinent called Pangea. He also hypothesised that the continents were slowly moving each year, but at such a slow rate we didn't notice that the continents are moving.
What did Wegener discover?
He discovered that fossils in the continents on the east of South America and the west of Africa were the same, or similar and used this to back up his theories. He also found similar animal fossils on each continent, which further proved his theory of continental drift.
What were Wegener's four theories?
Continental drift, Pangea, rock fossils and animal fossils/skeletons.