Consequently, Darwin found evidence that supported Lyell's hypothesis. After docking on the western coast of South America, Darwin traveled up the heights of the Andes Mountains. There, Darwin found seashells near the summit, an area well above sea level. Based on Lyell's research, Darwin hypothesized that the summit of the mountains must have been near the ocean floor during a historic period, one that would have been radically prior to the assumed origins of life on earth.
At this point, Darwin began to ponder the idea that if the literal interpretation of God and his divine creations kept falling by the wayside due to the mechanistic explanations that were becoming prevalent, why couldn't life be explained in the same fashion. Darwin's theory of natural selection and its impact on evolution originated from the Beagle's tour of the Galapagos Islands. He was tipped off by the dissimilar patterns that appeared on the different tortoises of the different islands. Darwin asked why God would divinely create different types of tortoises with diverse patterns in the same tropical region of earth. Darwin further wondered if they may have evolved different patterns by small changes over a very long period of time similar to the geology of the coastline. Darwin's beliefs were additionally strengthened during the voyage by the inevitable conversations with Captain Fitzroy, a biblical literalist. The two men would argue constantly, regarding thoughts occurring within the perimeter of Darwin's wandering mind. Captain Fitzroy would quote the Bible, as literalists do, and direct answers to God. Yet, Darwin found that none of the questions he asked were validly answered with the approach of divine creation. Consequently, Fitzroy's weak arguments strengthened Darwin's belief in evolution. .
Furthermore, Charles Darwin collected different birds from the different Galapagos Islands, all with different appearances yet striking similarities.