That's very interesting, because the other side of my family were Carolans (now spelt Carlin over here) from the same area of Cavan.
My great-grandfather, Thomas Carolan or Carlin, born 1833, left Ireland for Edinburgh in the 1880s with his wife Catherine Connelly or Connolly, and so sooner or later did all their children: Helen, Patrick, Catherine, Andrew (my grandfather), Thomas, Julia, Charles, Margaret and James. Some of these, maybe all, were born in Bailieborough between c. 1858 and 1875, and emigrated to Edinburgh in the 1880s. All except maybe Patrick married in Scotland, and they have descendants now in Scotland, England and the USA. A rather distant cousin has done a lot of research but mostly from the period after the family arrived in Edinburgh.
I haven't so far been able to find any records of my grandfather Andrew's birth in Cavan, nor those of any of his siblings, partly because the names are so common in Cavan that every search is potentially costly on IFHF. If you have any leads from previous generations of your own Carolans that could lead me back beyond this couple, Thomas Carlin and Catherine Connelly, married in the late 1850s, I would be most interested.
Though the Carolans, Lambe and McMahons were near neighbours in Cavan, and most of those who migrated to Edinburgh lived within a quite small area, my parents, so far as I know, were the first Carlin-McMahon union here.