Atrahasis, the hero of the Great Flood story, was a citizen of Shuruppak in lower Mesopotamia. An extensive flood as a natural event sometimes took place in that region, where the Euphrates in spate can overflow and spill across the intervening land into the lower-lying Tigris, which itself often breaks its own banks in sudden spate, but a flood would be impossible on a similar scale in Palestine, Syria, Anatolia, or Greece. Such floods occur quite commonly in Iraq, and strata of silt deposits on Early Dynastic sites of the fourth millennium BC, found there by archaeologists, can be interpreted as recording various different floods in remote antiquity. That evidence does not, however, disclose whether one particular flood was more catastrophic than others; it only shows that no unusual break in cultural continuity was caused by such a deposit, and that the layer of flood silt found in excavations at Ur is certainly much earlier in date than the flood deposit found at Shuruppak. No flood deposits are found in third millennium strata, and Archbishop Usher's date for the Flood of 2349 BC, which was calculated by using numbers in Genesis at face value, can not be substantiated by archaeology.