The Lost Worlds of Planet Earth Ortelius hypothesized the idea that land masses may have been connected in the past, Alfred Wegener who hypothesized the idea of a super-continent Pangaea and continental drift despite the prevailing idea of flooded land-bridges at the time, and Bruce C. Heezen and Marie Tharp who discovered the Mid-Atlantic Ridge that supported the theory of plate tectonics. Tyson describes how the landmasses of the earth lay atop the mantle, which moves due to the motion and heat of the earth's outer and inner core. Tyson moves on to explain the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals
Journey to the Center of the Earth Lyell's earlier ground-breaking work "Principles of Geology", published 1830–33). By that time geologists had abandoned a literal biblical account of Earth's development and it was generally thought that the end of the last glacial period marked the first appearance of humanity, but Lyell drew on new findings to put the origin of human beings much further back in the deep geological past. Lyell's book also influenced Louis Figuier's 1867 second edition of "La Terre avant le déluge" ("The Earth before the flood") which included dramatic illustrations of savage men and women wearing animal skins and wielding stone axes, in place