In none of these is there any mention of an universal deluge as an historical event actually occurring within the period of time embraced by those records. The only reference to such a deluge is contained in one chapter of a Chaldæan epic poem based on a solar myth, and placed in an immense and fabulous antiquity. In Egypt the case is, if possible, even stronger, for here the configuration of the Nile valley is such that anything approaching an universal deluge must have destroyed all traces of civilization, and buried the country thousands of feet under a deep ocean. Even a very great local inundation must have spread devastation far and wide and been a memorable event in all subsequent annals. When remarkable natural events, such as earthquakes, did occur, they are mentioned in the annals of the reigning king, but no mention is made of any deluge. On the contrary, all the records and monuments confirm the statement made by the priests of Heliopolis to Herodotus when they showed him the statues of the 360 successive high priests who had all been "mortal men, sons of mortal men," that during this long period there had been no change in the average duration of human life, and no departure from the ordinary course of nature. When this historical evidence is added to that of geology, which shows that nothing resembling a deluge could have occurred in the valleys of the Nile or Euphrates without leaving unmistakable traces of its passage which are totally absent, the demonstration seems as conclusive as that of any of the propositions of Euclid. It remains to consider how so many traditions of a deluge should be found among so many different races often so widely separated. There are three ways in which deluge-myths must have been inevitably originated. 1. From tradition of destructive local floods. 2. From the presence of marine shells on what is now dry land. 3. From the diffusion of solar myths like that of Izdubar. There can be no doubt that destructive local floods must have frequently occurred in ancient and prehistoric times as they do at the present day. Such an inundation as that of the Yang-tse-Kiang, which only the other year was said to have destroyed half a million of people, or the hurricane wave which swept over the Sunderbunds, must have left an impression which, among isolated and illiterate people, might readily take the form of an universal deluge. And such catastrophes must have been specially frequent in the early post-glacial period, when the ice-dams, which converted many valleys into lakes, were melting.