Hi Ron,
I have a copies of the pre 1855 MI's for East & West Stirlingshire and I had a wee look in Polmont Churchyard to see if I could find anything for you but unfortunately couldn't find anything. I also tried Muiravonside Churchyard which is just down the road but nothing there either.
Do you have a note of all James & Mary's children? If not, they were:
Mary, born 17.10.1792, christened 21.10.1792 (Polmont)
James, born 17.11.1794, christened 25.11.1794 (Pomont)
Jean, born 09.06.1798, christeed 13.06.1798 (Falkirk)
George, born 26.05.1799, christened 09.06.1799 (Falkirk)
Robert, born 05.04.1801, christened 12.04.1801 (Falkirk)
Jean, born 12.-3.1803, christened 27.03.1803 (Falkirk)
I looked for the birth of a James Rankine c1770 (the whole of Stirlingshire) and like you, came up with George Rankine and Jean Rea. This James was born 15th July 1770 and christened 22nd July 1770 in Pomont and was the 2nd of 6 children born to this couple, all in Pomont. All the names fit the traditional 'naming pattern' but of course this isn't proof. The siblngs of James were:
George, born 27.03.1765, christened 31.03 1765
James, born 15.07.1770, christened 22.07.1770
Agnes, borm 01.08.1773, christened 08.08.1773
Jean, born 16.13.1775, christened 24.12.1775
Margaret, born 25.09.1778, christened 27.09.1778
William, born 06.11.1781, christened 11.11.1781
I next looked for the birth of a Mary Main but widened the search to include Muiravonside (as there were none born in Polmont) and found the following children born to James Main & Mary Simpson:
Mary, no date of birth listed, christened 05.02.1766 (Muiravonside)
Christian, no date of birth listed, christened 05.05.1778 (Slamannan)
(When doing a 'parent search', all areas are included)
If this is the correct Mary, then she would have been 26 years old when Mary, the first child was born in 1792.
The above births are from the British Vital Records - a CD version of the IGI.
Without knowing where in Falkirk the remainder of James & Mary's children were born, it's not going to be easy to track them down.
Anne