New South Greenland
Filchner's view that the supposed sighting of New South Greenland could be explained by a mirage is echoed by Simpson-Housley. He suggests that Morrell and his crew saw a superior mirage. One form of superior mirage, sometimes described as a Fata Morgana, distorts distant flat coastlines or ice edges both vertically and horizontally, so they can appear to have tall cliffs and other features such as high mountain peaks and valleys. In his expedition account South, Shackleton gives a description of a Fata Morgana observed on  1915, coincidentally as his ship Endurance drifted close to the recorded position of New South Greenland: "The distant pack is thrown up into towering barrier-like cliffs, which are reflected in blue lakes and lanes of water at their base. Great white and golden cities of Oriental appearance at close intervals along these cliff-tops indicate distant bergs ... The lines rise and fall, tremble, dissipate, and reappear in an endless transformation scene".