There were two great glacial periods during the Atlantean era, followed by other less intense periods, which lasted one Saturn year (30 years). This was a natural reaction against quite torrid periods on the Earth.
While Lemurians lived intuitively and half-detached from their physical bodies, their material life was purely instinctive.
Human brain was a divine mass at the disposal of men, and they had to record on it little by little.