On the first day of the Conference, the Donatists challenged the list of the signatures of the Catholic bishops on the document in which they had assigned their representatives. The roll call followed, in which the tribune Marcellinus, who presided, called the Catholic bishops one by one, and their Donatist counterparts were to identify them. Then the roll call proceeded in the opposite way, with the Donatist bishops identified by the Catholics.

Although the Catholic bishop of Zuri (an analphabet!) claims that all are Catholics there, the Donatists protest that their diocese exists in this place in which they have a presbyter (possibly the episcopal see was temporarily vacant). The same situation repeats itself with  the diocese of Nigrensium Maiorum.

We do not know exactly where the Churches described as Zuriensis (the place been called hipothetically Zuri by Serge Lancel, whom I follow) and Nigrensium Maiorum were.