that this result was likely to have been attained in any case. Now, this may seem all the wildest speculation, but it is not entirely so, for if we examine a submarine contour map of the Straits of Gibraltar, we find there is an enormous valley running up from the Mediterranean deep, right through the Straits, and trenching some distance out on to the Atlantic shelf. This valley or gorge is probably the work of the inflowing waters of the ocean at the termination of the period of interior drainage."
This refilling of the Mediterranean, which by the rough chronology we are employing in this book may have happened somewhen between 30,000 and 10,000 b.c., must have been one of the greatest single events in the pre-history of our race. If the later date is the truer, then, as the reader will see plainly enough after reading the next two chapters, the crude beginnings of civilization, the first lake dwellings and the first cultivation, were probably round that eastern Levantine Lake into which there flowed not only the Nile, but the two great rivers that are now the Adriatic and the Red Sea. Suddenly the ocean waters began to break through over the westward hills and to pour in upon these primitive peoples—the lake that had been their home and friend became their enemy; its waters rose and never abated; their settlements were submerged; the waters pursued them in their flight. Day by day and year by year the waters spread up the valleys and drove mankind before them. Many must have been surrounded and caught by the continually rising salt flood. It knew no check; it came faster and faster; it rose over the tree-tops, over the hills, until it had filled the whole basin of the present Mediterranean and until it lapped the mountain cliffs of Arabia and Africa. Far away, long before the dawn of history, this catastrophe occurred.
