"When that Power awakes, then has this world its full expansion; but when he slumbers with a tranquil spirit, then the whole system fades away..... For while he reposes, as it were, embodied spirits endowed with principles of action depart from their several acts, and the mind itself becomes inert." The absorption of all beings into the Supreme essence is then described, and the Divine soul itself is said to slumber, and to remain for a time immersed in "the first idea, or in darkness." After which the text thus proceeds (verse fifty-seven), "Thus that immutable power by waking and reposing alternately, revivifies and destroys, in eternal succession, this whole assemblage of locomotive and immovable creatures." It is then declared that there has been a long succession of _manwantaras_, or periods, each of the duration of many thousand ages, and-- "There are creations also, and destructions of worlds innumerable: the Being, supremely exalted, performs all this with as much ease as if in sport, again and again, for the sake of conferring happiness."[2] No part of the Eastern cosmogony, from which these extracts are made, is more interesting to the geologist than the doctrine, so frequently alluded to, of the reiterated submersion of the land beneath the waters of a universal ocean. In the beginning of things, we are told, the First Sole Cause "with a thought created the waters," and then moved upon their surface in the form of Brahma the creator, by whose agency the emergence of the dry land was effected, and the peopling of the earth with plants, animals, celestial creatures, and man. Afterwards, as often as a general conflagration at the close of each manwantara had annihilated every visible and existing thing, Brahma, on awaking from his sleep, finds the whole world a shapeless ocean. Accordingly, in the legendary poems called the Puranas, composed at a later date than the Vedas, the three first Avatars or descents of the Deity upon earth have for their object to recover the land from the waters. For this purpose Vishnu is made successively to assume the form of a fish, a tortoise, and a boar.