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
The Man That Was Used Up story seems to suggest that the war hero has nothing left but the injuries he has received in battle to make up his identity. According to Shawn James Rosenheim, Poe also is questioning technology, suggesting that it will soon be difficult to distinguish man from machine. The story also has minor critiques of racism; the war hero was taken apart by Indians but is put together by his "old negro valet" named Pompey (a name Poe also uses in "A Predicament"), arguably undermining the power of white male dominance. Poe may also have been reacting to the popular "subversive" humor