You are right that your Mary married a John Parfitt from Camerton.John is a slight offshoot from my family tree.I have John being baptised on Dec 21 1835.He and Mary had three children, William, Frank and Edward.
Johnwas the son of James Parfit born 1808 and Mary Harding and had four sisters and one brother.
James was the son of Isaac Parfitt born 1779 and Lydia Skeats.James had three brothers and two sisters.
Isaac Parfitt was the son of James Parfit born about 1746 and Mary Parfect.Isaac had three brothers and one sister.All of the above male line were born in Camerton, Somerset.
James Parfit born 1725 in Stoke Lane, Somerset married a Joan Tailor in 1745 and had five children including James.I couldn't trace any further back than James as the records had been damaged by water.
If you want any more details contact me direct as I have a lot more information.