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.
The realization that the figure of the Earth is more accurately described as an ellipsoid dates to the 18th century (Maupertuis). In the early 19th century, the flattening of the earth ellipsoid was determined to be of the order of 1/300 (Delambre, Everest). The modern value as determined by the US DoD World Geodetic System since the 1960s is close to 1/298.25.