The headstone gives date of death for William and Janet Smart and also their daughter Margaret.
But does it give their ages at death?
There are two birth dates for Janet Smart 11 September 1767 (Thomas Smart & Mary Mitchell parents), 4 Jan 1769 (James Smart & Elizabeth Paterson parents). I cannot find any other Janet Smart being Christened in the time frame that would match.
There are
eight baptisms of Janet Smarts in Stirlinshire between 1740 and 1770. Why do you think that either of these two is the right one, when you know that they are both too young?
What you must
not do is assume that all baptism records have survived. There could be plenty more Janet Smarts whose baptism records have not survived. Or maybe your Janet Smart was not born in Stirlingshire.
Regarding William on their first childs Christening records it states that the witnesses were Robert Jaffray and Will Jaffray Senior. Now I have researched Williams whose father is also William and found one born 20 June 1745 to William Jaffray and Margaret Allison. What are your thoughts on this.
That sounds like a reasonable deduction.
Most info going around has Williams father as John Jaffray and the mother either Margaret Mitchell or Margaret Gillespi they put the birth date of 29 August 1730, but I cannot find any record of this.
If by 'most information going round' you mean submitted trees on Ancestry or any other similar commercial web site,
do not trust them. Never believe anything you find online unless it is an original document - and even then be wary; mistakes do occur.
