The city of Posidon, the ringed canal city also called the city of Atlantis for his son Atlas, was five miles inland from the ice age ocean shoreline, connected to the ocean by a three hundred foot wide canal which was an astounding one hundred feet deep, the ice age inland city now submerged (since circa 1400 b. c.) perhaps about thirty miles south of Cadiz. The canals around Atlantis need have been much less than a hundred feet deep to have accommodated the draughts of bronze age ships perhaps having required no more than a twenty foot deep canals, so the hundred foot depth of the canal to the ocean was to accommodate the variable tide such that the city was always connected to the ocean.
