Thanks, Dave.I did purchase the baptism record of James McCleary (MCCLEERY) from the IFHF, which is where I got the date of 8 Nov 1838 and the parents James McCleery and Mary Mahon.
The reason I was questioning IFHF's data is, my own ancestors were James McCleery and Mary Riley, who were also having children in Oldcastle at about that time.Since I couldn't find any other McCleary/Mahon children, I thought it possible that MAHON might have been an incorrectly transcribed RILEY.
There is, in fact, a niche for the birth of another child in Nov 1838, in between the birth of my proven ancestor Anthony McCleery (Nov 1837) and his sister Elizabeth (Oct 1839).Furthermore, traditional Irish naming practice would suggest that, if that child were the 3rd son, he be named after his father James!I thought that at very least I ought to look up the actual microfilmed record, so I could see this MAHON surname for myself.As luck would have it, Nov 1838 is missing!
As you suspected, there was in fact a marriage of one James McCleery and Mary Mahon on 16 Feb 1838.That page in the LDS microfilm is complete, and suggests that James McCleery and Mary Mahon were indeed a genuine couple, coexisting with my proven ancestors James McCleery and Mary Riley, who were married 22 Apr 1832.
Your suggestion that I take a harder look at the LDS microfilm, for pages out of order, is a good one.I'll try that next time I visit my "extended loan" microfilm.
I should mention that I have Boylen/McCleary cousins, descendants of my James McCleery and Mary Riley.It would be quite a coincidence if they were connected to your Boylan name.
Thanks again for your interest and suggestions.
Jim Ross g-g-grandson of James McCleary and Mary Riley