Thanks for all the above. Since this is 1665, shortly after the first Wm Gellin died, the "kinsman Wm Gelling" will be the nephew who died 1683. I believe Kath Gelling wife of Wm Creer of Ballnamoda will be the sister of the first Wm and aunt of the second Wm. So does this mean the latter Wm received a part of the Mill in 1663 from his uncle Wm and he purchased another part from his uncle and aunt Creer? Possibly.
Question about the use of terms "the elder" and "the younger" vs. "senior" and "junior". The 1665 deed has "William Creer the Younger" and has "William Gelling Jr" as a witness. Are the terms interchangeable or is that a way to differentiate father/son from two siblings of the same name? I've seen "John" and "John the other one" used too.
In the 1663 will of Wm Gelling, in both cases where he referred to "his brother's son William", there's a word following that I can't figure out. I've wondered if it's a form of "junior" but it doesn't look like it. I tried to scan my photostat copy of the will to post here, but it seems my scanner is now toast.