Berosus seems to have very carefully distinguished between the Assyrians and the Babylonians or Chaldaeans, as may be seen even through the doubly-distorting medium of Polyhistor and the Armenian Eusebius.

Diodorus Siculus made the two nations separate and hostile in very early times.

Pliny draws a clear line between the "Chaldaean races," of which Babylon was the head, and the Assyrians of the region above them.

Even Herodotus in one place admits a certain amount of ethnic difference; for, in his list of the nations forming the army of Xerxes, he mentions the Chaldaeans as serving with, but not included among, the Assyrians.
The grounds, then, upon which the supposed Semitic character of the ancient Chaldaeans has been based, fail, one and all; and it remains to consider whether we have data sufficient to justify us in determinately assigning them to any other stock.
Now a large amount of tradition--classical and other--brings Ethiopians into these parts, and connects, more or less distinctly, the early dwellers upon the Persian Gulf with the inhabitants of the Nile valley, especially with those upon its upper course.

Homer, speaking of the Ethiopians, says that they were "divided," and dwelt "at the ends of earth, towards the setting and the rising sun." This passage has been variously apprehended.