The document discusses evidence that supports the existence of ancient supercontinents. It describes geological studies in Africa that have found similarities in rock formations and drainage patterns across the continent, indicating the landmasses were once joined. Specifically, research on the African Rift Valley has uncovered matching volcanic rocks and river systems on either side of the rift that align with the theory of continental drift. Additionally, the same alkaline rock formations found in Africa are also seen in the boundaries of other ancient continents like Greenland and India, providing further evidence they were once attached as part of a supercontinent.