Wegener’s theory was not based on mere speculation; it was grounded in a variety of compelling evidence. One of the most striking pieces of evidence was the jigsaw fit of the continents. Wegener observed that the coastlines of South America and Africa appeared to fit together like pieces of a puzzle. This observation suggested that the two continents were once joined. Although the fit was not perfect due to erosion and changes in sea level, the overall similarity was too significant to ignore.
Another critical piece of evidence came from fossil records. Wegener noted that identical fossil remains of plants and animals were found on continents that are now separated by vast oceans. For example, the fossilized remains of the freshwater reptile Mesosaurus were found in both South America and Africa. Similarly, the fossilized remains of the fern-like plant Glossopteris were discovered in South America, Africa, India, Antarctica, and Australia. These findings indicated that these continents were once connected, allowing for the migration of species across a single landmass.
Wegener also relied on geological evidence to support his theory. He observed that mountain ranges and rock formations on different continents shared striking similarities in terms of age, composition, and structure. For instance, the Appalachian Mountains in North America and the Caledonian Mountains in Europe exhibited similar geological features, suggesting that they were once part of the same mountain range. Additionally, the presence of ancient glacial deposits in regions that are now near the equator, such as India and Africa, indicated that these areas were once located closer to the South Pole.
Climatological evidence further bolstered Wegener’s theory. He argued that the distribution of ancient climate zones, as inferred from geological records, could only be explained if the continents had moved. For example, coal deposits, which form in warm, swampy environments, were found in Antarctica, suggesting that the continent was once located in a warmer climate zone. Similarly, evidence of glacial activity in regions that are now tropical indicated that these areas were once situated in colder latitudes.
Wegener’s theory was revolutionary, but it was not without its challenges. Despite the compelling evidence, the scientific community initially struggled to accept his ideas due to the lack of a plausible mechanism for how the continents could move. It wasn’t until later research on plate tectonics provided a mechanism for continental movement that Wegener’s theory gained widespread acceptance.