On Fossils Found In South America and Africa from the Mesozoic and Paleozoic Ages Remarkably Resembling Each Other

 This is one of the major pieces of evidence used by early 20th Century geologists, Eduard Suess and Alfred Wegener, in forming their theory that the two large southern hemisphere land masses were at one point connected (the mechanism being the earth's relatively fluid interior allowing for land to slide across the mantle due to ice ages, earthquakes, etc.). And it must have been convincing in that what they submitted is now considered common knowledge and certainly a step up from previous theories, one of which actually included the lost continent of Atlantis (as a land-bridge), I shit you not.