Index to Marriage Records by Elder Hugh Reid 1858-1875 Erin Twp, Wellington Co. FHC film #1033998
Nodwell Mary and McArthur, James, 31 Jan 1866.  Note the spelling on the marriage record.  Colin Robertson was the witness at the wedding.  The marriage entry states Mary's place of birth to be America.  Would this mean North America or was she born in the US?  A copy of the entry is on file.

Ontario, Canada Marriages, 1857-1922 Record info about James McArthur
Name: James McArthur Birth Place: Scotland Residence: Erin Township Age: 27 Father Name: Peter McArthur Mother Name: Catharine McArthur Estimated Birth Year: 1839 Spouse Name: Mary Nodwell Spouse's Age: 24 Spouse Birth Place: Unites States Spouse Residence: Erin Township Spouse Estimated Birth Year: 1842 Spouse Father Name: Andrew Nodwell Spouse Mother Name : Isabella Nodwell Marriage Date: 31 Jan 1866 Marriage County: Wellington Family History Library Microfilm: 1030067