Mbh 3.270.1d

When at the close of four thousand Yugas the Earth thus became flooded with water, like one vast sea, and all mobile creatures were hushed in death, and the sun and the moon and the winds were all destroyed, and the Universe was devoid of planets and stars, the Supreme Being called Narayana, unknowable by the senses, adorned with a thousand heads and as many eyes and legs, became desirous of rest. And the serpent Sesha, looking terrible with his thousand hoods, and shining with the splendour of ten thousand suns, and white as the Kunda flower or the moon or a string of pearls, or the white lotus, or milk, or the fibres of a lotus stalk, served for his conch. And that adorable and omnipotent God thus slept on the bosom of the deep, enveloping all space with nocturnal gloom. And when his creative faculty was excited, he awoke and found the Universe denuded of everything. In this connection, the following sloka is recited respecting the meaning of Narayana. “Water was created by (the Rishi) Nara, and it formed his corpus; therefore do we hear it styled as Nara. And because it formed his Ayana (resting-place) therefore is he known as Narayana.” As soon as that everlasting Being was engaged in meditation for the re-creation of the Universe, a lotus flower instantaneously came into existence from his navel, and the four-faced Brahma came out of that navel-lotus. And then the Grandsire of all creatures, seating himself on that flower and finding that the whole Universe was a blank, created in his own likeness, and from his will, the (nine) great Rishis, Marichi and others. And these in their turn observing the same thing, completed the creation, by creating Yakshas, Rakshas, Pisachas, reptiles, men, and all mobile and immobile creatures. The Supreme Spirit hath three conditions. In the form of Brahma, he is the Creator, and in the form of Vishnu he is the Preserver, and in his form as Rudra, he is the Destroyer of the Universe!