James Green and Mary????

[flower fairy]

I am trying to find the maiden name of my 3x's great grandmother. She was born in approx 1800 in Sampford, Courtney (from the 1851 census) and called Mary???. In about 1825 she married James Green and the igi says they married in  Tiverton although I am inclined to think they were married more in the area they lived which would have been Chulmeigh. How can I go about trying to find her maiden name, I am stuck unless I can find this out. Any ideas please???