Is there by any chance a mention of John Stewart?
He was born in Balquhidder in 1796/7, married Mary Scott in East Kilbride in 1830, and had six of a family. In 1851 he was described as a coal miner in the census, when the family was at Auchenheath.
The next reference I have is to a possible death of Mary in Maryland, USA in 1875. I don't know if it's the right Mary, and if so whether John died before she emigrated, or whether he also emigrated and died in North America.