George Crossan

This entry is for my 3rd Great Grandfather, George Crossan.   His son, my 2nd great grandfather, George Crossan (I'll call him George Jr), born about  1831 in Ireland, married Rebecca Connelly in Glasgow in 1858. George Jr's marriage certificate gives his father's name as George Crossan also and his mother was Helen Boyle nee Campbell (or possibly Campbell nee Boyle).  My submission here is for the father, who I assume may have been born about 1800-1810. There was another family of Crossans in Glasgow at the time as George Jr's wedding who were very close to George and Rebecca (witnessing weddings and sponsoring baptisms) and I believe they would be George's cousins. Their father was a James Crossan, married to a Catherine Cranshay and then a Catherine Bonar/Bonnar.  I have DNA connections to Crossans in North West Ireland, specifically Michael Crossan in Carnanbane Townland, Londonderry - born about 1800 - and James Crossan, Carrick Townland, Templemore, Donegal - born about 1805.   The James Crossan in Carrick is an appropriate age to be George's uncle and would make me 5th cousin to one of my DNA contacts - which fits.   My father once said he thought he'd heard the Crossans came from Carrickfergus, but he also heard we were from Derry, so it seems highly possible what he overheard as a child was Carrick. I have also found an earlier George Crossan, born about 1781 who was in Knockybrin Townland.  He cannot be my George Jr's father as he was still allive in 1858 when George described him on his marriage certificate as deceased.   I wonder if he could be from the generation before my George's father and the James in Carrick.  A lot of this is conjecture, obviously.  I'm interested in anything anyone and can add and hope to visit Donegal sometime this year to explore more.  George Jr and his wife Rebecca married in a Catholic Church.   I've assumed he was catholic from his birth in Ireland.  The family continued in the Catholic faith.