Thank you for your response. It looks as if this Ann McIntosh could be correct. I wasn't too clear in my post - I'm wondering if O'Kain J. Cameron had a sister or aunt named Isabelle or Isabella. An Isabella Cameron, born in Canada in the 1790s married Thomas Payne in Glengarry (not sure about the date. In the 1851/52 Census, Isabella and Thomas lived in Chichester, Quebec. The name O'Kain occurs frequently in my husband's Cameron family.
(not sure about the date)