Task: Question Generation
Input (English): Passage: From the earliest navigations of the Southern Ocean in the 16th century, lands which subsequently proved to be nonexistent had  from time to time been reported.  Robert Headland of the Scott Polar Research Institute has suggested various reasons for these false sightings, ranging from "too much rum" to deliberate hoaxes designed to lure rival ships away from good sealing grounds. Some sightings may have been of large ice masses that were carrying rocks and other glacial debris—dirty ice can appear convincingly similar to land. It is also possible that some of these lands existed, but later became submerged after volcanic eruptions. Other sightings may have been of actual land, the position of which was wrongly fixed through observational errors arising from chronometer failure, adverse weather or simple incompetence.At 2 pm on 15 March, as Wasp cruised north-eastwards, Morrell records: "Land was seen from the masthead, bearing west, distance 3 leagues" (about nine miles, 14 km). He did not at the time consider that he had made a new discovery; he seems to have assumed that he was seeing the east coast of the Antarctic Peninsula, the western coast of which had been explored and given the name New South Greenland in 1821, by Robert Johnson, a former captain of the Wasp.  Johnson's name for this land was never adopted; in 1831 it was named Graham Land. At the time of Morrell's voyage, the geographical character and dimensions of the peninsula were  unknown; Morrell's recorded position was in fact far to the east of the peninsula. Morrell's account reads: "At half past 4 pm we were close on with the body of land to which Captain Johnson had given the name of New South Greenland".  The next few days were spent exploring this supposed coast, which was apparently rich in seal. Some 75 miles (120 km) further south, Morrell thought he could see snow-covered mountains.After three days, Morrell called a halt "because of shortage of water and season far advanced". Wasp turned north, from a position Morrell calculated as 67°52'S, 48°11'W,  and on 19 March, the ship passed what he assumed was the northern cape of the land, at 62°41'S, 47°21'W. "This land abounds with oceanic birds of every description", wrote Morrell.  He also records seeing 3,000 sea elephants. At 10 o'clock Wasp "bade farewell to the cheerless shores of New South Greenland", and sailed for Tierra del Fuego, then through the Magellan Strait into the Pacific Ocean, reaching  Valparaiso, Chile, on 26 July 1823.
Output (English): The reporting of land masses which later prove to be nonexistent is sometimes called what?