Thanks for all that information! It's good to have background in mind, for context. Interesting O'Kelly research, Hallmark, I wonder where you access these handwritten trees? They would be very nice to have in full and to study at leisure. Are they among those references you give to the Library? If so, I must go sometime.
Nice information about Barrett origins, truly an ancient family of Mayo by all accounts it seems. Shevlanes seem to still evade us - but that was a very interesting snippet from 1815, Castlebar. Bearing in mind Castlebar isn't where I've been focussing though. However I do see some Anthony Shevlanes later on, and perhaps there is a connection. It seems people stayed close to their townships but movement wouldn't have been that strange either.
I've yet to add in details of Shevlanes at "Tallagh", thus far only put down Shevlanes of Briska and Shevlanes of Shragh. More on this later. Will come back to the registers this weekend I think.