Michael, the actual spelling is Glencullin - there is Upper and Lower Glencullin (the enumerator would have spelt it as he heard it)
Civil Parish of Kilcommon
Barony of Erris
Poor Law Union Belmullet
Catholic Diocese Killala
Catholic Parish (1) Kilcommon-Erris (2) Belmullet
I think this is the LDS film No: 127905 and that should have Baptisms from 1859 and Marriages 1860.
There is another Glencullin between Westport and Louisburg.
Civil Parish of Glencullin
Barony of Murrish
Poor Law Union Westport
Catholic Diocese Tuam
Catholic Parish Louisberg (Kilgeever)
(this area would make more sense, but a lot further from Ballina)
I'm just a bit concerned that there is no other info to 'prove' the Ruane name against these areas. Was Patrick a farmer? or did they live in the villages and work as labourers. Were there any other children left behind that you could check on the 1901 Mayo Census (gave you the web site - see above)
I'll keep checking. Happy hunting
Dee