The first of these, Tepe Gawra, was excavated in the 1930s when stratigraphic controls were lacking, causing difficulties in re-creating the sequence.
[4] A. L. Perkins identified the existence of a Halaf-Ubaid Transition phase that can be seen in ceramic assemblages.
Sites like Tell el-'Oueili, and Choga Mami in the Mandali region were suggested as witnesses to this phase.
[5] More recently, a Halaf-Ubaid Transitional phase has been attested in Syria, in such places as Tell Zeidan, Tell Aqab, Tell Kurdu, Tell Masaikh (near Terqa, also known as Kar-Assurnasirpal, pl:Kar-Aszurnasirpal), and Chagar Bazar.
Recent analysis (2016) indicates that, in the Ashur region, as well as on the Shahrizor Plain, the settlement intensity, as well as the overall site numbers remained rather similar throughout the Halaf and Ubaid periods.