As Skarsaune notes (pg. 196):1. The chronology of the bishops of Jerusalem I have nowhere found preserved in writing; for tradition says that they were all short lived.
2. But I have learned this much from writings [plural], that until the siege of the Jews, which took place under Adrian, there were fifteen bishops in succession there, all of whom are said to have been of Hebrew descent, and to have received the knowledge of Christ in purity, so that they were approved by those who were able to judge of such matters, and were deemed worthy of the episcopate. For their whole church consisted then of believing Hebrews who continued from the days of the apostles until the siege which took place at this time; in which siege the Jews, having again rebelled against the Romans, were conquered after severe battles.
3. But since the bishops of the circumcision ceased at this time, it is proper to give here a list of their names from the beginning. The first, then, was James, the so-called brother of the Lord; the second, Symeon; the third, Justus; the fourth, Zacchæus; the fifth, Tobias; the sixth, Benjamin; the seventh, John; the eighth, Matthias; the ninth, Philip; the tenth, Seneca; the eleventh, Justus; the twelfth, Levi; the thirteenth, Ephres; the fourteenth, Joseph; and finally, the fifteenth, Judas.
4. These are the bishops of Jerusalem that lived between the age of the apostles and the time referred to, all of them belonging to the circumcision.
Skarsaune says in note 37 to this that he is following Bauckham in Jude and the Relatives of Jesus in the Early Church pages 70-79, but those pages aren't viewable for me on Google books, so I can't check that. Nor can I find the Letter of James to Quadratus.There is obviously something wrong with this list: from the death of James (A.D. 62) until A.D. 135 (73 years) there is not room for fifteen leaders in succession; all the more so since we are told [by Hegesippus] that Symeon alone reigned into the time of Hadrian; his martyrdom may have occurred sometime ca. A.D. 100-110. This leaves the remaining thirteen "bishops" with something like two years each, and explains Eusebius' bewilderment that no dates were given in his source for the list, and his conclusion that the Jewish bishops must have been exceedingly short lived! There are other sources, however, which supplement Eusebius and may give us the clue he lacked. Some of the last twelve names on his list occur in an apocryphal Letter of James to Quadatus, in which these names are said to be the names of the elders who assisted James in leading the church. This could mean that only the first three on Eusebius' list succeeded each other as "bishops," while the last twelve were members of a presbyter circle formed on the pattern of the twelve apostles. Symeon could have reigned some forty years as leader, and after him Justus some thirty years.
https://books.google.com/books?id=IAlQT ... em&f=false
But the important thing is that Hegesippus does leave very little room for thirteen more bishops after Simeon since he says that Simeon ruled from c. 62 CE to the time of Trajan (not Hadrian as Skarsaune says, though he gives the right date for Trajan, c. 100-110 CE), along with Eusebius' statement that "The chronology of the bishops of Jerusalem I have nowhere found preserved in writing."