Hi Alistair
I have got further back on the Yeats family. It's just Mary's family that's difficult. I know that she was alive in 1851, and that she was dead by 1859. The children, in the main, seem to follow traditional naming conventions. That ought to mean that her parents should be James and Mary, assuming that I have no children missing.
She was born, according to the census, in Tarbert, Argyllshire. However she and her husband married in Paisley. Although most of the children were also born in Tarbert, the last child was born in Paisley, and the family was in Paisley for the 1841 and 1851 censuses. I know her name from death certificates and marriage certificates of several children.
I haven't been able to find her death in scotlandspeople. The IGI has several listings for Mary McNab, but just nothing that I can hang my hat on.
That's it. That's all that I have. She's a very elusive lady.
As for the Yeats, the ones in Erskine in Volume 1 are quite likely to be part of this family. I know that you don't have Volume 1, but does the index show Robert Yates and/or Elizabeth (Gaie) Yates?
Isobel