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 Name of the Doctor in other places in time and space. She enters the time stream to restore the Doctor's timeline. Echoes of Clara fall through space and time and appear in adventures of the Doctor's previous incarnations. The Doctor enters the column of light to save the original Clara, guiding her from a place where she sees several previous incarnations of the Doctor. Reunited, the two spot another figure in the shadows which Clara does not recognise. The Doctor explains the elderly figure is another past incarnation of himself, but what he did in the past was not in the Doctor's name. Imagery