The deposit of soil, however, may not have been so rapid in the flourishing days of Babylonian history, when the canals were carefully attended to and the irrigation of the country kept under control. It is safer, therefore, to assume for the period preceding the rise of the Macedonian Empire a rate of deposit of not more than one hundred feet each year. The seaport of primitive Chaldea was Eridu, not far from Ur, and as the mounds of Abu-Shahrein or Nowâwis, which now mark its site, are nearly one hundred and thirty miles from the present line of coast, we must go back as far as 6500 B.C. for the foundation of the town. "Ur of the Chaldees," as it is called in the Book of Genesis, was some thirty miles to the north, and on the same side of the Euphrates; the ruins of its great temple of the Moon-god are now known by the name of Muqayyar or Mugheir. It must have been founded on the sandy plateau of the Arabian desert at a time when the plain enclosed between the Tigris and the Euphrates was still too marshy for human habitation. As the Moon-god of Ur was held to be the son of El-lil of Nippur, Dr. Peters is doubtless right in believing that Ur was a colony of the latter city. Nippur is the modern Niffer or Nuffar in the north of Babylonia, and recent excavations have shown that its temple was the chief sanctuary and religious centre of the civilized eastern world in the earliest epoch to which our records reach. Eridu, Ur, and Nippur seem to have been the three chief cities of primeval Babylonia. As we shall see in a future chapter, Eridu and Nippur were the centres from which the early culture and religion of the country were diffused. But there was an essential difference between them. Ea, the god of Eridu, was a god of light and beneficence, who employed his divine wisdom in healing the sick and restoring the dead to life. He had given man all the elements of civilization; rising each morning out of his palace under the waters of the deep, he taught them the arts and sciences, the industries and manners, of civilized life. El-lil of Nippur, on the contrary, was the lord of the underworld; magical spells and incantations were his gifts to mankind, and his kingdom was over the dead rather than the living. The culture which emanated from Eridu and Nippur was thus of a wholly different kind. Is it possible that the settlers in the two cities were of a different race?