The following genealogy is taken from a text within the O Clery Book of Genealogies  a genealogical collection compiled in the seventeenth century. The names of most of those appearing in the terminal generations have been omitted for reasons of clarity. The numbers in square brackets are the paragraph numbers in the published edition. Names have been standardised. It has not been possible to determine where the line in paragraph 311 fits into the wider genealogy.
|__________________________________ | | | Domhnall of Cameirge An Epscop An Oifistel An Eoghanach   killed 1241 |___________________________________________________________ | | Aedh Murchadh | | Diarmaid gallóglaigh Eoghan mor killed 1260 | | | Niall Niall |_____________________________ | | | | | Donncha bui Cathal dubh Sean Eoghan | | died 1375 | | | | | Brian oge Emann Felim Emann dorcha Niall | | | | |_________ | | | | | | 5 sons Domhnall cron Niall murrae Brian balbh Aibhne An Oifistel  | | |   3 sons 4 sons 3 sons | |    | | continues elsewhere
Domhnall of Cameirge is described as an eoghanach ('the member of Cenél nEoghain') which in context would seem to be an office of pre-eminence among the Cenél nEoghain. Dates where shown are the result of cross referencing individuals in the genealogy to other historical records, so we find that the Annals of Ulster record the killing of Domhnall at the battle of Cameirge in 1241 and the killing of Diarmaid at the battle of Down in 1260 while the Annals of the Four Masters record in 1375 the death of Sean the chief of the clan. The legal and administrative text entitled Ceart Uí Néill ('Right of O Neill') preserves a picture of the political geography of Inishowen as it existed prior to the O Doherty annexation that indicates the demesne lands of the lords of Inishowen were exempted from the general obligation to billet O Neill's forces because there was a force of mercenaries stationed there . This finds resonance in the gallóglaigh ('foreign fighters') epithet given to Diarmaid which in context clearly refers to the bands of Scottish mercenaries hired by Irish lords from the thirteenth century onwards. The ecclesiastical records mention persons bearing as names in religion the latinised Goffredus and the devotional Michael but unfortunately their secular names remain unknown. Goffredus bore his latinised name as a canon of the chapter of Derry cathedral and was elected bishop of Derry by the chapter by 1297 . Michael bore his devotional name as a member of the Franciscan order of Friars Minor and had been elected archbishop of Armagh by the chapter of Armagh cathedral by 1306 but his election was not admitted by the Holy See . It would seem that Michael was the son of a nun and so rendered ineligible to hold offices in his order or dignities within the Church until receiving a dispensation from the Holy See in 1310 . By 1319 he was bishop of Derry  so it would appear that the couplet of an epscop ('the bishop') and an oifistel ('the official') can be resolved onto Goffredus and Michael in a portion of the genealogy that can be dated to the period circa 1297x1319 when Goffredus was bishop and Michael was the official, a person appointed to the ecclesiastical office of vicar-general in temporals who as principal judicial and administrative officer of the bishop presided at the ecclesiastical consistory court. The integration of this portion into the genealogy as a whole does present certain problems as it is unlikely that Domhnall alive in 1241 could have been the brother of Goffredus alive in 1315 or Michael alive in 1319. Given that this portion occurs in a non-standard narrative rather than the standard genealogical formulae of the remainder of the text it would seem likely that Goffredus and Michael having left no living descendants but remembered from an earlier text of circa 1297x1319 as remote collaterals holding high office were misplaced by a generation or two when the post-1241 genealogy was first compiled into written form.
The other MacLochlainns named in the historical records from this time do not appear in the genealogy. Taken together with its stem-like appearance this tells us that the genealogy is typical in that it records only certain ascents and is not a comprehensive record of all descending ramifications. The annals tell us of Seisilin who died in 1250 , Sitrec who was attacked in 1298 , Muircheartach who was killed in 1303  and Cormac son of Muircheartach who was killed in 1345  while the ecclesiastical records tell us of Nicholao Lochlannach ('Nicholas, a MacLochlainn') whose secular name is unknown but who bore his devotional name as a member of the Dominican order of Friars Preachers being prior of their house in Derry by 1397, Domhnall who was a canon of the chapter of Derry cathedral by 1397  holding the rectory of Moville as a prebend until his death 1397x1412  and Pádraig Lochlannach ('Pádraig, a MacLochlainn') who was vicar of Grallagh and Culdaff from 1425 until his death 1425x1429 while on pilgrimage in Rome . Unfortunately with the exception of Seisilin who can be identified as a daughter of Domhnall of Cameirge the relationship of these people to the genealogy as a whole can not now be recovered.