My Biggest Historical Clan Problem

What is my biggest clan genealogical problem? What would be the biggest breakthrough I would like to happen before I revise my first draft of the Clan History? Most of my clan Family Trees start in Ulster and end up all over the world. My earliest Family Trees start in Scotland and end up all over the world. What I believe must have happened is that the 'earliest' people in the Ulster trees must have hopped over the water from Scotland to Ireland and in consequence transplanted our clan trees from one country to the other. But do I have an indisputable 'Mr. X' who on an indisputable date boarded a boat in Ayr or Irvine or Stranraer and landed in Larne or Derry or Islandmagee? No I don't. But surely it had to have happened. Would that I could find such a person.

For a time I thought I had a candidate. In a Scottish family which certainly goes back to 1780 and perhaps much earlier, we have a Richard McElhago or McIlhaggert, born in 1832 to James and Jane McIlhaggert in Dundonald, Ayrshire, who became a sailor and died in 1891. In Ireland there is a marriage of a Richard, son of James McIlhagart, who married Ellener Boyd in 1860. Were the two Richards one and the same? However, there are two problems. I'm sure the Scottish Richard remained single. We know this from a Poorhouse Application made shortly before his death. Second, the Irish Richard's surname on the marriage record is Kennedy! Had Richard changed his surname? Was he an 'adopted' son? We don't know. So I must conclude that I haven't got a candidate for a clan male who went 'over the sea' to Ulster.

I am also left with the mystery of which clan family was involved in the marriage. The marriage record gives Richard's father as James McIlhagart and names his spouse as Ellener Boyd, daughter of Thomas Boyd. The marriage took place on 7th June 1860 in Donegore, County Antrim. This was a Church marriage in Donegore 1st Presbyterian Church, by License, by the Revd. W.J. Gillespie. James' witness was Thomas Boyd, presumably Ellener's father. Her witness was Margaret Boal. Richard Kennedy is listed under the Griffith Land Valuation (1862) at Browndod, the townland named on his marriage record. His landlord was the Marquis of Donegal from whom he rented a house, offices and land of just over 34 acres, and for which he paid a total of £20.10s.0d. per annum. Similarly Thomas Boyd farmed in Ballynoe townland, Donegore parish. There is no James McIlhagart in the Griffith Valuation in these places, though there is a James McElhagan who is a tenant in Kinbally townland, just a few miles to the north. If anyone can shed any light on how this family fits into a clan 'tree' I would be delighted to hear from them.