The country itself was an alluvial plain, formed by the silt deposited each year by the Tigris and Euphrates.

The land grows at the rate of about ninety feet a year, or less than two miles in a century; since the age of Alexander the Great the waters of the Persian Gulf have receded more than forty-six miles from the shore.

When the Sumerians first settled by the banks of the Euphrates it must have been on the sandy plateau to the west of the river where the city of Ur, the modern Mugheir, was afterwards built.

At that time the future Babylonia was a pestiferous marsh, inundated by the unchecked overflow of the rivers which flowed through it.

The reclamation of the marsh was the first work of the new-comers.