 Later research concerning the paleoclimatology and ice sheets of Antarctica have discredited the interpretations by Hapgood that an Antarctic warm period coincided with the last glacial period in the Northern Hemisphere and that any part of it had been ice-free at and prior to 9,600 BCE (approx.11,600 years ago).Hapgood also examined a 1531 map by French mathematician and cartographer Oronce Finé (aka "Oronteus Finaeus").