Now in Arabia , not far from Egypt , there is a gulf extending inland from the sea called Red , whose length and width are such as I shall show: in length, from its inner end out to the wide sea, it is a forty days' voyage for a ship rowed by oars; and in breadth, it is half a day's voyage at the widest. Every day the tides ebb and flow in it. I believe that where Egypt is now, there was once another such gulf; this extended from the northern sea towards Aethiopia, and the other, the Arabian gulf of which I shall speak, extended from the south towards Syria ; the ends of these gulfs penetrated into the country near each other, and but a little space of land separated them. Now, if the Nile inclined to direct its current into this Arabian gulf, why should the latter not be silted up by it inside of twenty thousand years? In fact, I expect that it would be silted up inside of ten thousand years. Is it to be doubted, then, that in the ages before my birth a gulf even much greater than this should have been silted up by a river so great and so busy?