Courtneys in Somerset or Devon?

I am caught between 2 shires. The marrage record of my Great, Great Grandfather when he first arrived in Newfoundland shows him being from Somertshire but most of my cousins tell me he came from Devon. There appears to be more Courtneys in Devon, especially Barnstable area, than in Somersetshire.He would have left England probably in the 1820s to go to Newfoundland.