Cryosol | Soil Monoliths Cryosols (or Gelisols in USDA Soil Taxonomy) have permafrost either within 1 m of the surface or within 2 m if the pedon is strongly cryoturbated in the active layer. Monoliths.soilweb.ca
Among the ancient Greeks, Homer thought the world to be flat. In contrast, Pythagoras postulated that the earth was round. A century later, Aristotle sided with the theory of the roundness of the earth.
Most educated persons in Columbus' day accepted a round earth. But there was difference of opinion about the earth's size. Columbus made the mistake of relying on Ptolemey's value for the size of the earth, which was much too small. Columbus therefore underestimated the length of the proposed voyage.