[Little Bill]

There is some evidence that the el-'Ubaid culture was inturupted, with a layer of silt and mud seperating the begining and continuation of the culture that developed into Sumeria.

Dosen't quite fit in to this time line though, I wonder if the "Bull From Heaven" is significant.

[John Beresford Tipton]

re the Bull from Heaven:

In Gilgamesh, because he refuses to marry the Godess Ishtar, she goes to the head God and receives permission to bring the Bull of Heaven down to earth to kick Gilgamesh's ass. The rest of the story, and the meteorite of Anu are also represented there. See also my post 60