Well according to the stone David married both Ann Grieg and Margaret Davidson.
And just to confuse the matter even further, there's another David Hay stone, a fancy flat stone;
13. Janet Raitt 21.3.1758 57, h David Hay mason in Tulloh of Berv(ie) d 17.10.176(3) 60, das Janet Hay (9).6.1738 (2) y, Mary Hay 22.2.1758 14, also Kath Hay 179(
61. The sunglasses smiley should be an 8 but keeps coming up as a smiley instead!
Jean 
Well! I'm really happy I stopped in here, in a bittersweet way - LOL...looks like I have some tree pruning to do.
I think I originally got this line from a now 83 yr old cousin...that would be about 15 years ago. And, considering the dates, I can see why I've never questioned it.This is the second time I've trusted the elders and it went sideways. I found it hard to find records for that period and just left it.
As for David Hay and Janet Raitt - I have them down as "suspects" possible parents of David Hay m Anne Grieg.
So, Mr David was real busy making kids when he was past 60. Wow.
I'm going to have to backtrack for a bit and see what's up here. If you come across any other tidbits - do show and tell!
More later, and thank you doesn't come close...
Pat